Datasheet LX1563IM, LX1563IDM, LX1562IM, LX1562IDM Datasheet (Microsemi Corporation)

Page 1
A
LIN DOC #:
1562
LX1562/1563
S ECOND-GENERATION POWER FACTOR CONTROLLER
THE INFINITE POWER OF INNOVATION
DESCRIPTION KEY FEATURES
The LX1562 is a second-generation family of power factor correction controllers using a discontinuous mode of operation. They are optimized for electronic ballast applications. Many improvements have been made over the original SG3561A controller introduced by Silicon General Semicon­ductor in 1992.
New features include the addition of an internal start-up circuit eliminating bulky external components while allowing independent boost converter operation. Addition of internal current sense blanking eliminating the need for an external R/C filter network. Internal clamping of the error amplifier and multiplier outputs improves turn on overshoot characteristics and current limiting. Special circuitry has also been
added to prevent no load runaway conditions. And finally, output drive clamps limiting power MOSFET gate drive independent of supply voltage greatly enhance the products practical application.
Although the IC design has been optimized for electronic ballast applica­tions, it can also be used for power factor correction in lower power (typ < 300W) AC-DC converters. One unique feature of the device is encompassed by the addition of internal logic circuitry to detect zero crossing of the inductor current thus maintaining the discontinuous current mode of opera­tion. This feature prevents large current gaps from appearing thereby minimizing distortion and enhancing power factor correction.
PRODUCT HIGHLIGHT
TYPICAL APPLICATION OF THE LX1562 IN AN 80W
F
LUORESCENT LAMP BALLAST WITH ACTIVE POWER FACTOR CONTROL
450µH
61T #22AWG
L1
AC-
C+
120V
AC
D1 D3
EMI FILTER
D2
1N4004
1N4004
1N4004
1N4004
100k
½W
R3
2.2M
R1
1%
1µF
C1
250V
D4
29k
R2
1%
C4
.01µF
7T
D5
22µF
R10
4.7M
1N4935
C2
C3
R4
22k
0.1µF
3
VINI
MULT
IN
8
DET
COMP
LX1562
GND
6
5
OUT
INV
C.S.
1N4148
7
2
1 4
D6
47
R5
R9 620k
C5
0.1µF
1/4W
P RODUCTION DATA SHEET
■■
INTERNAL START-UP CIRCUIT
■■
■■
INTERNAL CURRENT SENSE BLANKING
■■
■■
IMPROVED MICROPOWER START-UP
■■
CURRENT (300µA max.)
CLAMPED E.A. OUTPUT FOR LOWER
TURN-ON OVERSHOOT
MULTIPLIER CLAMP LIMITS MAXIMUM
INPUT CURRENT
■■
INTERNAL OVERVOLTAGE PROTECTION
■■
REPLACES BUILT-IN C.S. OFFSET
■■
PWM OUTPUT CLAMP LIMITS MOSFET
■■
GATE DRIVE VOLTAGE
INCREASED UVLO HYSTERESIS REDUCES
START-UP TIMING (LX1562 only)
LOW OPERATING CURRENT CONSUMPTION
INTERNAL 1.5% REFERENCE
TOTEM POLE OUTPUT STAGE
AUTOMATIC CURRENT LIMITING OF BOOST
STAGE
DISCONTINUOUS MODE OF OPERATION
WITH NO CURRENT GAPS
NO SLOPE COMPENSATION REQUIRED
APPLICATIONS
V
BOOST
MR854
230V
D7
1M
R7
1%
Q1
1RF730
11k
1%
3x
R6
1.3
C6 100µF 400V
R8
FLOURESCENT LAMP BALLAST
■■
ELECTRONIC BALLAST
■■
SWITCHING POWER SUPPLIES
A VAILABLE OPTIONS PER PART #
Part # Start-Up Hysteresis
LX1562 13.1V 5.2V
LX1563 9.8V 2.1V
Voltage Voltage
Note: Thick trace on schematic shows high-frequency, high-current path in circuit.
Lead lengths must be minimized to avoid high-frequency noise problems.
PACKAGE ORDER INFORMATION
T
(°C)
A
0 to 100 LX1562IM LX1562IDM
Plastic DIP
M
8-pin
Plastic SOIC
DM
8-pin
0 to 100 LX1563IM LX1563IDM
Note: All surface-mount packages are available in Tape & Reel.
Append the letter "T" to part number. (i.e. LX1562IDMT)
FOR FURTHER INFORMATION CALL (714) 898-8121
Copyright © 1996 Rev. 1.3 12/96
11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841
1
Page 2
LX1562/1563
PRODUCT DATABOOK 1996/1997
S ECOND-GENERATION POWER FACTOR CONTROLLER
RODUCTION DATA SHEET
P
ABSOLUTE MAXIMUM RATINGS (Note 1)
Supply Voltage (VIN) ...................................................................................... -0.3V to 28V
Peak Driver Output Current (Note 3) ................................................................. ±500mA
Driver Output Clamping Diodes
V
> VCC or VO < -0.3V ........................................................................................ ±10mA
O
Detector Clamping Diodes
> 6V or V
V
DET
Error Amp, Multiplier, and Comparator Input Voltages ................................ -0.3V to 6V
< 0.9V ..................................................................................... ±10mA
DET
Detector Input Voltage (Note 2) ....................................................................... -0.3 to 6V
Operating Junction Temperature
Plastic (M and DM Packages) ............................................................................... 150°C
Storage Temperature Range ...................................................................... -65°C to 150°C
Lead Temperature (Soldering, 10 Seconds) ............................................................ 300°C
Note 1. Values beyond which damage may occur. All voltages are specified with respect to
ground, and all currents are positive into the specified terminal. Note 2. With no limiting resistor. Note 3. Current duty cycle is chosen such that T
is below 150°C.
J
THERMAL DATA
M PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θθ
θ
θθ
JA
DM PACKAGE:
D
θθ
θ
θθ
x θ
JA
).
JA
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
Junction Temperature Calculation: TJ = TA + (P
numbers are guidelines for the thermal performance of the device/pc-board system.
The θ
JA
All of the above assume no ambient airflow
95°C/W
165°C/W
PACKAGE PIN OUTS
E.A. INV. E.A. OUT
MULT. INPUT
E.A. INV. E.A. OUT
MULT. INPUT
C.S.
1 8 27 36 45
C.S.
M PACKAGE
(Top View)
1 8 27 36 45
DM PACKAGE
(Top View)
V OUT GROUND I
IN
DET
V
IN
OUT GROUND I
DET
2
Copyright © 1996
Rev. 1.3 12/96
Page 3
PRODUCT DATABOOK 1996/1997
LX1562/1563
S ECOND-GENERATION POWER FACTOR CONTROLLER
P RODUCTION DATA SHEET
RECOMMENDED OPERATING CONDITIONS (Note 4)
Parameter
Symbol
Supply Voltage Range Peak Driver Output Current
Operating Ambient Temperature Range:
LX1562/1563
Note 4. Range over which the device is functional.
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, these specifications apply over the operating ambient temperatures for the LX1562/1563 with 0°C ≤ TA ≤ 100°C; V testing techniques are used which maintains junction and case temperatures equal to the ambient temperature.)
Parameter
Symbol
Test Conditions
Under-Voltage Lockout Section
Start Threshold Voltage V
UV Lockout Hysteresis V
ST
H
LX1562 Only LX1563 Only
LX1562 Only
LX1563 Only
Supply Current Section
Start-Up Supply Current I
Operating Supply Current I Dynamic Operating Supply Current I
VIN < V
ST
Q
OP
TH
VIN = 12V, Output Not Switching VIN = 12V, 50kHz, CGS = 1000pF
Reference Section (Note 5)
Initial Accuracy (Note 8) VRI
Line Regulation V Load Regulation V Temperature Stability V
= 0mA, TA = 25°C
REF
= 0mA
I
REF
12V < VIN < 25V
I
0 < I
L
T
< 2mA
REF
Error Amplifier Section
Input Bias Current I
Large Signal Open Loop Voltage Gain A Slew Rate S
Power Supply Rejection Ratio (Note 5) PSRR 11 to 25V Output Source Current I
Output Sink Current I
Output Voltage Range (Note 7) E.A. Unity Gain Bandwidth f
Phase Margin φ
B
(Note 5)
VOL
VOH = 3V
SR
VOL = 2V
SK
No Load on E.A. Output
O
B
B
Multiplier Section
Mult. Input Voltage Range V
M2 Input Voltage Range V
Mult. Input Bias Current (M1) I Multiplier Gain (Note 5 & 6) K V
Multiplier Gain Temperature Stability K
Maximum Multiplier Output Voltage V
M1
M2
MB
V
T
CLMPVM1
= 1V, V
M1
M1
= 2V, V
EA0
= 0.5V to 1.5V, V
PIN1
= 2.7V to 3.3V
= V
EA0
= 0V
REF
+ 1V
(Electrical Characteristics continue next page.)
Recommended Operating Conditions
Min. Typ. Max.
11 25 V
±200 mA
0 100 °C
LX1562I/1563I
Min. Typ. Max.
12 13.1 14 V
9.2 9.8 10.6 V
4 5.2 6 V
1.7 2.1 2.5 V
2.465 2.50 2.535 V
2.44 2.56 V
-500 50 500 nA 60 80 dB
60 80 dB
-2 -4.5 mA 3 4.5 mA
1.2 3.8 V
02V
V
REF
0.55 0.68 0.8 V/V
0.55 0.61 0.75 V/V
1.1 1.24 1.45 V
Units
=12V. Low duty cycle pulse
IN
Units
200 300 µA
58mA
610mA
0.1 mV
1.3 mV 20 m V
0.63 V/µsec
1.7 MHz 49 °
V
+ 1 V
-0.24 µA
-0.2 %/°C
REF
2
2
Copyright © 1996 Rev. 1.3 12/96
3
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PRODUCT DATABOOK 1996/1997
LX1562/1563
S ECOND-GENERATION POWER FACTOR CONTROLLER
RODUCTION DATA SHEET
P
ELECTRICAL CHARACTERISTICS (Con't.)
Parameter
Symbol
Test Conditions
Current Sense Comparator Section
Input Bias Current I Current Sense Delay to Output t
C.S. Blanking Time t
C.S. Input Offset Voltage V
0V VCS 1.7V
CSB
E.A.
d
BLK
OFFVEA0
= 3.7V, VCS = 0 to 1.2V, VM1 = 1V
OUT
= 2.2V, VM1 = 0V, I
DETC
= 0V
Detect Section
Input Voltage Threshold - High V Hysteresis H
Input LO Clamp Voltage V
Input HI Clamp Voltage V Input Current I
Input HI/LO Clamp Diode Current I
HI
D
DLIDET
DZIDET
1V V
DB
DMXVDET
= 100µA
= 3mA
6V
DET
< 0.9V, V
DET
> 6V
Restart Timer Section
Restart Time t
RST
Output Driver Section
Output High Voltage V
Output Low Voltage V
Output Rise Time t Output Fall Time tfCL = 1000pF
Maximum Output Voltage V
Notes: 5. Because the reference is not brought out externally, these specifications are tested at probe only, and cannot be tested on the packaged part.
They are guaranteed by design, and shown for illustrative purposes only.
V
6. K = (V
) x (V
M1
C.S.
- V
)
EA0
REF
(V
M1
7. This parameter, although guaranteed, is not tested in production.
8. Initial accuracy includes input offset voltage of error amplifier.
= -10mA, VIN = 12V
PRHIL
= 10mA, VIN = 12V
PRLIL
CL = 1000pF
R
DRMXVIN
V
C.S.
) (V
)
EA0
= 20V
LX1562I/1563I
Min. Typ. Max.
-1 -0.3 1 µA 280 500 ns
0.4 0.9 1.2 µs
-20 3 20 mV
1.6 1.72 1.9 V 180 240 300 mV
0.4 0.62 0.85 V
7.0 7.8 8.6 V
-1 -0.2 1 µA
300 µsec
8.5 9 V
0.8 1 V
130 200 ns
50 120 ns
13 13.8 15 V
Units
±3 mA
4
Copyright © 1996
Rev. 1.3 12/96
Page 5
PRODUCT DATABOOK 1996/1997
S ECOND-GENERATION POWER FACTOR CONTROLLER
P RODUCTION DATA SHEET
BLOCK DIAGRAM / PIN DESCRIPTIONS
LX1562/1563
E.A. INV.
1
2
E.A. OUT
V
OUT
7
C.S.
4
C1
L1
D1
IN
AC
Internal
V
IN
8
L1
300
13.1V (1562)
9.8V (1563)
1.72V
MULT
IN
3
I
DET
5
L1
5.2V (1562)
2.1V (1563)
V
REF
V
TIMER
Bias
6.8V To All
Internal Circuitry
UVLO
R
S
1µs
Delay
LATCH
2.5V REF
Q
1.24V
C.S.
Q
M1
V
REF
Input
M2
1.8V
EMI
Filter
V
C.S.
REF
FUNCTIONAL DESCRIPTION
Pin # Description
V
GND 6
INV 1
E.A. OUT 2
MULT IN 3
C.S. 4
I
DET
OUT 7
8
IN
Input supply voltage.
Input supply voltage return. Must always be the lowest potential of all the pins.
Inverting input of the Error Amplifier. The output of the Boost converter should be resistively divided to 2.5V and connected to this pin.
The output of the Error Amplifier. A feedback compensation network is placed between this pin and the INV pin.
Input to the multiplier stage. The full-wave rectified AC is divided to less than 2V and is connected to this pin.
Input to the PWM comparator. Current is sensed in the Boost stage MOSFET by a resistor in the source lead, and is fed to this pin. An internal blanking circuit eliminates the RC low pass filter that otherwise is required to eliminate leading edge spike.
5
A current driven logic input with internal clamp. A second winding on the Boost inductor senses the flyback voltage associated with the zero crossing of the inductor current and feeds it to the I
PWM output pin. A totem-pole output stage specially designed for direct driving the MOSFET.
pin through a limiting resistor. Low on this pin causes VO (pin 7) to go high.
DET
Copyright © 1996 Rev. 1.3 12/96
5
Page 6
LX1562/1563
PRODUCT DATABOOK 1996/1997
S ECOND-GENERATION POWER FACTOR CONTROLLER
RODUCTION DATA SHEET
P
GRAPH / CURVE INDEX
Characteristic Curves
FIGURE #
1. E.A. OUTPUT VOLTAGE vs. C.S. THRESHOLD
2. MULTIPLIER INPUT VOLTAGE vs. C.S. THRESHOLD
=1V, V
3. MULTIPLIER GAIN (V
4. REFERENCE VOLTAGE (Including Offset) vs. TEMPERATURE
5. E.A. INPUT BIAS CURRENT vs. TEMPERATURE
6. E.A. SINK CURRENT @2V vs. TEMPERATURE
7. START-UP SUPPLY CURRENT vs. TEMPERATURE (LX1563)
8. START-UP SUPPLY CURRENT vs. TEMPERATURE (LX1562)
9. START-UP THRESHOLD vs. TEMPERATURE (LX1562)
10. START-UP THRESHOLD vs. TEMPERATURE (LX1563)
11. UV LOCKOUT HYSTERESIS vs. TEMPERATURE (LX1562)
12. UV LOCKOUT HYSTERESIS vs. TEMPERATURE (LX1563)
THRESHOLD HIGH vs. TEMPERATURE
13. I
DET
14. I
INPUT HYSTERESIS vs. TEMPERATURE
DET
15. RUN-AWAY COMPARATOR THRESHOLD vs. TEMPERATURE
16. C.S. DELAY TO OUTPUT vs. TEMPERATURE
17. C.S. BLANKING TIME vs. TEMPERATURE
18. RESTART TIME vs. TEMPERATURE
19. FALL TIME vs. TEMPERATURE
20. RISE TIME vs. TEMPERATURE
21. SUPPLY CURRENT vs. SUPPLY VOLTAGE (LX1562)
22. SUPPLY CURRENT vs. SUPPLY VOLTAGE (LX1563)
22a. MAXIMUM MULTIPLIER OUTPUT VOLTAGE vs. TEMPERATURE
M1
=3.5V) vs. TEMPERATURE
EA0
FIGURE INDEX
IC Description
FIGURE #
23. INDUCT CURRENT
24. TYPICAL APPLICATION OF START-UP CIRCUITRY
25. START-UP CAPACITOR VOLTAGE
26. VOLTAGE REFERENCE vs. TEMPERATURE
27. THE AMPLIFIER CONFIGURED AS AN INTEGRATOR FOR LOOP
COMPENSATION
28. MULTIPLIER SECTION
29. CURRENT SENSE SECTION
30. START-UP TIMER
Application Information
FIGURE #
31. TYPICAL APPLICATION OF THE LX1562 IN AN 80W FLUORESCENT
LAMP BALLAST WITH ACTIVE POWER FACTOR CONTROL
32. NORMALIZED OPERATING FREQUENCY vs. OFF-TIME DUTY CYCLE
33. INDUCT CURRENT
34. LOAD TRANSIENT RESPONSE CIRCUIT
35. FLYBACK VOLTAGE ACROSS I
WINDING
DET
Typical Applications
FIGURE #
36. TYPICAL APPLICATION OF THE LX1562 IN AN 80W FLUORESCENT
LAMP BALLAST WITH ACTIVE POWER FACTOR CONTROL - 120V
37. TYPICAL APPLICATION OF THE LX1562 IN AN 80W FLUORESCENT
LAMP BALLAST WITH ACTIVE POWER FACTOR CONTROL - 220V
38. TYPICAL APPLICATION OF THE LX1562 IN AN 80W FLUORESCENT
LAMP BALLAST WITH ACTIVE POWER FACTOR CONTROL - 277V
6
Copyright © 1996
Rev. 1.3 12/96
Page 7
PRODUCT DATABOOK 1996/1997
2.47
2.45
(TA) Ambient Temperature - (°C)
2.52
(V
R
) Reference Voltage - (V)
2.48
-50
-25 0
25
50 75 100 125
VCC = 12V C
L
= 1nF
2.46
2.49
2.50
2.51
)
4
)
S ECOND-GENERATION POWER FACTOR CONTROLLER
P RODUCTION DATA SHEET
CHARACTERISTIC CURVES
LX1562/1563
FIGURE 1.E.A. OUTPUT VOLTAGE vs. C.S. THRESHOLD
1.4
VM1 = 3V
1.2
VM1 = 2.5V
1.0
0.8
0.6
C.S. Threshold - (V)
0.4
0.2
VM1 = 1.5V
VM1 = 2V
VM1 = 1V
TA = 25°C
0
2.6
2.4 2.8
3.233.43.6
3.8
E.A. Output Voltage - (V
FIGURE 3.MULTIPLIER GAIN (V
vs. TEMPERATURE
=1V, V
M1
EA0
=3.5V)
FIGURE 2.
1.4
1.2
1.0
0.8
0.6
0.4
C.S. Threshold Voltage - (V)
0.2
0
MULTIPLIER INPUT VOLTAGE vs. C.S. THRESHOLD
V
= 4V
EA0
V
= 3.5V
EA0
0.4
00.8
1.61.2 2 2.4
TA = 25°C
V
= 3V
EA0
V
= 3.25V
EA0
V
EA0
Multiplier Input Voltage - (V
FIGURE 4.REFERENCE VOLTAGE (Including Offset)
vs. TEMPERATURE
= 2.5V
3.2
3.62.8
0.80
0.75
0.70
0.65
0.60
(K) Multiplier Gain - (1/V)
0.55
0.50
-50
Copyright © 1996 Rev. 1.3 12/96
-25 0
25
50 75 100 125
(TA) Ambient Temperature - (°C)
VCC = 12V
= 1nF
C
L
V
= 3.5V
EA0
V
= 1V
M1
7
Page 8
LX1562/1563
100.0
0.0
(TA) Ambient Temperature - (°C)
350.0
(I
ST
) Start-up Supply Current - (µA)
150.0
-50
-25 0
25
50 75 100 125
VIN < V
TH
CL = 1nF
50.0
200.0
250.0
300.0
LX1562
4.0
3.0
(TA) Ambient Temperature - (°C)
6.0
(I
SK
) E.A. Sink Current @2V - (mA)
4.5
-50
-25 0
25
50 75 100 125
VCC = 12V C
L
= 1nF
V
EA0
= 2V
3.5
5.0
5.5
PRODUCT DATABOOK 1996/1997
S ECOND-GENERATION POWER FACTOR CONTROLLER
RODUCTION DATA SHEET
P
CHARACTERISTIC CURVES
FIGURE 5.E.A. INPUT BIAS CURRENT vs. TEMPERATURE
0.5
0.4
0.3
0.2
0.1
0.0
-0.1
-0.2
) E.A. Input Bias Current - (µA)
-0.3
B
(I
-0.4
-0.5
-50
-25 0
25
VCC = 12V C
= 1nF
L
E.A.- = 2.5V
50 75 100 125
FIGURE 6.
E.A. SINK CURRENT @2V vs. TEMPERATURE
(TA) Ambient Temperature - (°C)
FIGURE 7.START-UP SUPPLY CURRENT vs. TEMPERATURE FIGURE 8.START-UP SUPPLY CURRENT vs. TEMPERATURE
350.0
LX1563
0.0
-50
VIN < V CL = 1nF
-25 0
(TA) Ambient Temperature - (°C)
300.0
250.0
200.0
150.0
8
100.0
) Start-up Supply Current - (µA)
ST
50.0
(I
TH
25
50 75 100 125
Copyright © 1996
Rev. 1.3 12/96
Page 9
PRODUCT DATABOOK 1996/1997
9.60
9.40
(TA) Ambient Temperature - (°C)
(V
ST
) Start-up Threshold
-50 -25 0
25
50 75 100 125
9.50
LX1563
9.70
9.80
9.90
10.00
10.10
10.20
VCC = 0V to 16V C
L
= 1nF
S ECOND-GENERATION POWER FACTOR CONTROLLER
P RODUCTION DATA SHEET
CHARACTERISTIC CURVES
LX1562/1563
FIGURE 9.START-UP THRESHOLD vs. TEMPERATURE
14.0
FIGURE 10.
START-UP THRESHOLD vs. TEMPERATURE
LX1562
13.5
13.0
12.5
12.0
) Start-up Threshold - (V)
ST
(V
11.5
11.0
-50
-25 0
25
VCC = 0V to 16V
= 1nF
C
L
50 75 100 125
(TA) Ambient Temperature - (°C)
FIGURE 11.UV LOCKOUT HYSTERESIS vs. TEMPERATURE FIGURE 12.UV LOCKOUT HYSTERESIS vs. TEMPERATURE
Copyright © 1996 Rev. 1.3 12/96
) UV Lockout Hysteresis - (V)
H
V
(
6.0
5.5
5.0
4.5
4.0
3.5
3.0
-50
LX1562
-25 0
25
50 75 100 125
(TA) Ambient Temperature - (°C)
2.50
2.40
2.30
2.20
2.10
2.00
1.90
1.80
) UV Lockout Hysteresis - (V)
H
1.70
V
(
1.60
1.50
LX1563
-50 -25 0
25
(TA) Ambient Temperature - (°C)
50 75 100 125
9
Page 10
LX1562/1563
250
150
(TA) Ambient Temperature - (°C)
500
(t
d
) C.S. Delay to Output - (ns)
300
-50
-25 0
25
50 75 100 125
VCC = 12V, CL = 1nF V
M1
= 1V, V
EA0
= 3.7V
V
CS
= 0V to 1.2V
200
350
400
450
100
0
(TA) Ambient Temperature - (°C)
(H
D
) I
DET
Input Hysteresis - (mV)
-50 -25 0
25
50 75 100 125
50
150
200
250
300
350
400
PRODUCT DATABOOK 1996/1997
S ECOND-GENERATION POWER FACTOR CONTROLLER
RODUCTION DATA SHEET
P
CHARACTERISTIC CURVES
FIGURE 13.I
1.90
1.85
1.80
1.75
1.70
Threshold High - (V)
1.65
DET
) I
1.60
HI
THRESHOLD HIGH vs. TEMPERATURE
DET
(V
1.55
1.50
-50 -25 0
25
50 75 100 125
(TA) Ambient Temperature - (°C)
FIGURE 15.RUN-AWAY COMPARATOR THRESHOLD
vs. TEMPERATURE
FIGURE 14.
I
INPUT HYSTERESIS vs. TEMPERATURE
DET
FIGURE 16.C.S. DELAY TO OUTPUT vs. TEMPERATURE
2.8
2.6
2.4
2.2
10
2.0
1.8
1.6
Run-Away Comp. Threshold
1.4
1.2
-50 -25 0
25
50 75 100 125
(TA) Ambient Temperature - (°C)
Copyright © 1996
Rev. 1.3 12/96
Page 11
PRODUCT DATABOOK 1996/1997
80
40
(TA) Ambient Temperature - (°C)
(t
R
) Rise Time - (ns)
-50 -25 0
25
50 75 100 125
60
100
120
140
160
180
200
VCC = 12V C
L
= 2200pF
200
0
(TA) Ambient Temperature - (°C)
600
(t
RST
) Restart Time - (µs)
300
-50
-25 0
25
50 75 100 125
VCC = 12V C.S. = Pulse
100
400
500
S ECOND-GENERATION POWER FACTOR CONTROLLER
P RODUCTION DATA SHEET
CHARACTERISTIC CURVES
LX1562/1563
FIGURE 17.C.S. BLANKING TIME vs. TEMPERATURE
1000
900
800
700
600
500
) C.S. Blanking Time - (ns)
BLK
(t
400
300
-50
-25 0
25
50 75 100 125
FIGURE 18.
RESTART TIME vs. TEMPERATURE
(TA) Ambient Temperature - (°C)
FIGURE 19.FALL TIME vs. TEMPERATURE FIGURE 20.RISE TIME vs. TEMPERATURE
Copyright © 1996 Rev. 1.3 12/96
) Fall Time - (ns)
F
(t
90
80
70
60
50
40
30
20
-50
VCC = 12V, CL = 2200pF
-25 0
25
50 75 100 125
(TA) Ambient Temperature - (°C)
11
Page 12
LX1562/1563
PRODUCT DATABOOK 1996/1997
S ECOND-GENERATION POWER FACTOR CONTROLLER
RODUCTION DATA SHEET
P
CHARACTERISTIC CURVES
FIGURE 21.SUPPLY CURRENT vs. SUPPLY VOLTAGE
14
LX1562
12
10
8
6
4
) Supply Current - (mA)
CC
(I
2
0
01020
30
TA = 25°C
= 0V
V
CS
V
= 0V
M1
V
= V
PIN2
PIN1
40 50 60
(VCC) Supply Voltage - (V)
FIGURE 22a.MAXIMUM MULTIPLIER OUTPUT vs. TEMPERATURE
FIGURE 22.
14
SUPPLY CURRENT vs. SUPPLY VOLTAGE
LX1563
12
10
8
6
4
) Supply Current - (mA)
CC
(I
2
0
01020
(VCC) Supply Voltage - (V)
30
TA = 25°C
= 0V
V
CS
V
= 0V
M1
V
= V
PIN2
PIN1
40 50 60
12
1.45
VCC = 12V, CL = 1nF
1.40
1.35
1.30
1.25
1.20
1.15
1.10
) Maximum Mult. Output Voltage - (V)
1.05
CLMP
(V
1.00
= 0V, VM1 = 2V, VCS = 0-2V
V
PIN1
-50
-25 0
25
50 75 100 125
(TA) Ambient Temperature - (°C)
Copyright © 1996
Rev. 1.3 12/96
Page 13
PRODUCT DATABOOK 1996/1997
Rectified AC Line
GND
LX1562
GND
V
O
V
IN
IST < 300µA
I
1
> 300µA
C1
R1
R
S
D1
S ECOND-GENERATION POWER FACTOR CONTROLLER
P RODUCTION DATA SHEET
FUNCTIONAL DESCRIPTION
LX1562/1563
The operation of the IC is best described by referring to the block-diagram. The output of the multiplier stage generates a voltage proportional to the product of the rectified AC line and the output of the error amplifier. This voltage serves as the reference for the inductor peak current that is sensed by the resistor in series with the external power MOSFET. When the sense voltage exceeds this threshold, C.S. comparator trips and resets the latch as well as turning the power MOSFET off.
The energy stored during switch on-time is now transferred
and stored in the output capacitor, causing the inductor current
Inductor Peak Current Envelope
Average AC Input Current
FIGURE 23 — INDUCTOR CURRENT
TONT
UNDERVOLTAGE LOCK OUT
The LX1562/63 undervoltage lock-out is designed to maintain an ultra low quiescent current of less than 300µA, while guar­anteeing the IC is fully functional before the output stage is activated. Comparing this to the SG3561A device, a 40% reduc­tion in start-up current is achieved, resulting in 40% less power dissipation in the start-up resistor. This is especially important in electronic ballast applications that are designed to operate in harsh environments, with convection cooling as the only means of heat dissipation.
Figure 24 shows an efficient supply voltage using the ultra low start-up current of the LX1562 in conjunction with a boot­strap winding off of the power transformer. Circuit operation is as follows:
The start-up capacitor (C1) is charged by current through resistor (R1) minus the start-up current drawn by the IC. This resistor is typically chosen to provide 2X the maximum start-up current at low line to guarantee start-up under the worst case condition. Once the capacitor voltage reaches the start-up threshold, the IC turns on, starting the switching cycle. The operation of the IC demands an increase in operating current which results in discharging the capacitor. During the discharge cycle, the flyback voltage of the auxiliary winding is rectified and filtered via rectifier (D1) and charges the capacitor above the minimum operating voltage of the device and takes over as the supply voltage. The start-up capacitor and auxiliary wind­ing must be selected such that it satisfies worst case IC condi­tions. Figure 25 shows start-up time and voltage of capacitor C1.
to ramp down. When current reaches zero level (inductor runs out of energy) , boost diode (D1) stops conducting and the residual inductor energy and the drain to source capacitance of the power MOSFET create an LC tank circuit which causes drain voltage to resonate at this frequency. The resonating voltage is detected by the secondary winding (Idet winding) of the in­ductor. When this voltage swings negative “I detect” pin senses it and activates the blanking circuit , sets the latch, and turns power MOSFET on, repeating the cycle. This operation contin­ues for the entire cycle of the AC rectified input resulting in an inductor current as shown in Figure 23. The high frequency
I
L
content of this current is then filtered by the input capacitor (C1) resulting in a sine wave input current in phase with the AC line voltage.
Output voltage regulation is accomplished when the error amplifier compares this voltage to an internal 2.5V reference and generates an error voltage. This voltage then controls the amplitude of the multiplier output adjusting the peak inductor current proportional to the load and line variations, maintain-
OFF
ing a well regulated voltage.
IC DESCRIPTION
Table 1 shows the start-up voltage and hysteresis for LX1562 and LX1563. The LX1562 is used for stand alone pre-regulator applications while LX1563 is ideal for applications where sup­ply voltage is derived elsewhere and requires less than 14V start-up.
FIGURE 24 — TYPICAL APPLICATION OF START-UP CIRCUITRY
T ABLE 1
Part # Start-Up Hysteresis
Voltage Voltage
LX1562 13.1V 5.2V
LX1563 9.8V 2.1V
Copyright © 1996 Rev. 1.3 12/96
13
Page 14
LX1562/1563
PRODUCT DATABOOK 1996/1997
S ECOND-GENERATION POWER FACTOR CONTROLLER
RODUCTION DATA SHEET
P
IC DESCRIPTION
VOLTAGE REFERENCE (continued)
V
C1
V
START
V
HYST
RT & CT TIME CONSTANT
FIGURE 25 — START-UP CAPACITOR VOLTAGE
C1
DISCHARGE
DISCHARGE TIME
BOOTSTRAP WINDING
VOLTAGE REFERENCE
The voltage reference is a low drift bandgap design which pro­vides a stable +2.5V output with maximum of ±1.5% initial ac­curacy. This voltage is internally tied to the non-inverting in­put of the amplifier and is not available for external connec­tion. The initial accuracy of the reference includes error am­plifier input offset voltage. Figure 26 shows typical variation of the reference voltage vs. temperature.
2.52
2.51
2.50
VCC = 12V
= 1nF
C
L
ERROR AMPLIFIER
The error amplifier is an internally compensated op-amp with access to the inverting input and the output pin. The non­inverting input is internally connected to the voltage reference and is not available for external connection. The amplifier is designed for an open loop gain of 80dB, along with a typical bandwidth of 1.7MHz and 49 degrees of phase margin. The boost output voltage of the power factor pre-regulator is di­vided down and monitored by the inverting input. Input bias current (0.5µA max) can cause an output voltage error that is equal to the product of the input bias current and the value of the upper divider resistor. The amplifier's output is available for external loop compensation. Typically, the loop bandwidth is set below 10Hz in order to reject the low frequency ripple associated with 2X the line frequency. For example, if the
t
error amplifier is configured as an integrator with 1.2Hz band­width, it will have 40dB ripple rejection at 120Hz frequency. This means that if the output of the error amp is allowed to have 100mV of ripple, the boost converter must be limited to less than 10V of ripple on its output.
To prevent boost output run away condition that may occur during removal of the output load, a separate comparator moni­tors the E.A. output voltage and compares it to an internal 1.8V reference. When load is removed, E.A. output swings lower than 1.8V, trips the comparator and turns output driver off till the inverting input voltage drops below 2.5V. At this point, the E.A. output swings positive, turns the output driver back on and repeats the cycle until the load is returned to normal con­dition.
To reduce output overshoot during line and load transients, the E.A. output is clamped to two diode drops above the refer­ence voltage. This prohibits the amplifier from being satu­rated, allowing it to recover faster thus minimizing the boost voltage overshoot.
2.49
2.48
2.47
) Reference Voltage - (V)
R
(V
2.46
2.45
-50
-25 0
25
50 75 100 125
(TA) Ambient Temperature - (°C)
FIGURE 26 REFERENCE VOLTAGE (Including Offset) vs. TEMPERATURE
14
V
R10
O
R9
I
9
1
Bias
V
C4
REF
1.8V
From I
BW =
I9 >> I
2
Logic
DET
1
π
R9 C4
2
BIAS
2f
f = Line Freq.
FIGURE 27 — THE AMPLIFIER CONFIGURED AS AN INTEGRATOR
FOR LOOP COMPENSATION
OUTPUT
7
DRIVE
Copyright © 1996
Rev. 1.3 12/96
Page 15
PRODUCT DATABOOK 1996/1997
S ECOND-GENERATION POWER FACTOR CONTROLLER
P RODUCTION DATA SHEET
IC DESCRIPTION
MULTIPLIER
The LX1562/63 features a one quadrant multiplier stage having two inputs. One (VM2) is internally driven by a DC voltage which is the difference of E.A. output and V is connected to an external resistor divider monitoring the rec­tified AC line. The output of the multiplier which is a function of both inputs, controls inductor peak current during each cycle of operation. This allows the inductor peak current to follow the AC line thus forcing the average input current to be sinu­soidal.
The multiplier is in the linear region if the V to less than 2V and the E.A. output is kept below 3.5V under all line and load conditions. The output is internally clamped to
1.24V typically to limit the MOSFET peak current during turn on or under excessive load conditions. The equation below de­scribes the relationship between multiplier output voltage and the its inputs.
V
= K * V
M0
M1
*
(V
EA0
- V
REF
)
where: K = Multiplier gain (typ. 0.65)
V
= Voltage at pin3 (0 to 2V)
M1
V
= Error amp output voltage (2.5 to 3.5V)
EA0
= Multiplier output voltage
V
M0
E.A.
OUTPUT
2
V
EA
Σ
V
INV.
INPUT
AC
R1
R2
1
V
REF
2.5V
V
3
M1
FIGURE 28 — MULTIPLIER SECTION
CURRENT SENSE COMPARATOR
Current sense comparator is configured as a PNP input differ­ential stage with one input internally tied to the multiplier out­put and the other available for current sensing. Current is con­verted to voltage using an external sense resistor in series with the external power MOSFET. When sense voltage exceeds the threshold set by the multiplier output, the current sense com­parator terminates the gate drive to the MOSFET and resets the PWM latch. The latch insures that the output remains in a low state after the switch current falls back to zero. The LX1562/63 features a leading edge blanking circuit that eliminates the need
. The other (VM1),
REF
input is limited
M1
MULT.
OUTPUT
V
V
M2
M0
C.S.
INPUT
4
LX1562/1563
for an external RC filter otherwise required for proper opera­tion of the circuit. This function is described in detail under “current detect logic” section.
The current sense comparator voltage is limited by an inter­nal 1.24V (typ.) voltage clamp of the multiplier output. There­fore maximum switch current is typically given by:
I
= 1.24V / R
PK (MAX)
Maximum switch peak current happens at full load and mini­mum line conditions.
TO
PIN 7
3
R
S
V
M0
5
FIGURE 29 — CURRENT SENSE SECTION
CURRENT DETECT LOGIC
The function of “current detect logic” is to sense the operating state of the boost inductor and to enable the output driver accordingly. To achieve this, the downward slope of the in­ductor current is indirectly detected by monitoring the voltage across a separate winding and connecting it to the detector input “I level, the voltage across the winding reverses polarity and changes the “I state (See Figure 30). When comparator changes state, it sets
” pin. Once the inductor current reaches ground
DET
” input and the comparator output to the low
DET
the latch and turns on the output driver for a period of 1µs (typ.) regardless of any changes in the latch output (Q) within this period. This ensures that if the C.S. comparator changes state due to any turn-on spike, the driver output remains on and does not turn off prematurely.
However if the spike lasts longer than 1µs, the output driver turns off and the MOSFET stops conducting. This type of digi­tal current sense blanking which is not amplitude dependent has higher noise immunity than the commonly used external RC filtering, allowing for more flexibility in board layout.
Since inductor voltage swings both positive and negative, internal voltage clamping is provided to protect the IC. The
S
Logic
Circuit
R
1µsec Blank
7
Copyright © 1996 Rev. 1.3 12/96
15
Page 16
LX1562/1563
PRODUCT DATABOOK 1996/1997
S ECOND-GENERATION POWER FACTOR CONTROLLER
RODUCTION DATA SHEET
P
IC DESCRIPTION
CURRENT DETECT LOGIC (continued)
upper 7.8V clamp prevents input overvoltage breakdown dur-
switch off time, while during the on time the lower 0.7V
ing clamp prevents substrate injection. An internal current limit
resistor protects the lower clamp transistor in case the “I is accidently shorted to ground.
DET
” pin
START-UP TIMER
A start-up timer circuit eliminates the need for an external os­cillator when used in stand alone applications. The timer, as shown in Figure 30, provides a means to automatically start the pre converter if the latch output Q comes up in a wrong (HI) state. The timer capacitor ramps up and resets the latch to a low state, turning the output driver on.
V
REF
I
DEF
300
5
L1
V
1.72V
TIMER
C.S.
C.S. Latch
OUTPUT DRIVER STAGE
The LX1562/63 output driver is designed for direct driving of an external power MOSFET. It is a totem pole stage with ±500mA peak current capability. This typically results in a 130ns rise and fall times into a 1000pF capacitive load. Addi­tionally the output is held low during the undervoltage condi­tion to ensure that the MOSFET remains in the off state until supply voltage reaches the start-up threshold.
Internal voltage clamping ensures that output driver is al­ways lower than 13.8V (typ.) when supply voltage variation exceeds more than rated V nal MOSFET. This eliminates an external zener diode and extra
threshold (typ 20V) of the exter-
GS
power dissipation associated with it that otherwise is required for reliable circuit operation.
HI
C.S.
V
M0
S
1µs
Delay
R
Q
Q
L1
OUT
7
C.S.
4
16
FIGURE 30 — START-UP TIMER & CURRENT DETECT LOGIC CIRCUITRY
Copyright © 1996
Rev. 1.3 12/96
Page 17
PRODUCT DATABOOK 1996/1997
A
S ECOND-GENERATION POWER FACTOR CONTROLLER
P RODUCTION DATA SHEET
APPLICATION INFORMATION
TYPICAL APPLICATION
The application circuit shown in Figure 31 uses the LX1562 as the controller to implement a boost type power factor regulator. The I.C. controls the regulator, such that the inductor current is always operating in a discontinuous conduction mode with no current gaps. This mode of operation has several advantages over the fixed frequency discontinuous conduction mode: 1) The switch­ing frequency adjusts itself to the AC line envelope, causing a sinusoidal current draw, 2) Since there is no current gap between the switching cycles, the inductor voltage does not oscillate, causing less radiated noise, 3) The lower peak inductor current causes less power dissipation in the power MOSFET.
LX1562/1563
A set of formulas have been derived specifically for this mode, and are used throughout the design procedure. An example with the following specifications for the boost converter is given as:
Input Voltage Range - 100 to 130V RMS
Output Power - 80W
Efficiency - 95% at full load
Power Factor - > 0.99 at full load
Total Harmonic Distortion - < 10% at full load
followed by a step by step design procedure which walks through component selection.
AC-
C+
120V
AC
450µH
61T #22AWG
L1
100k
D1 D3
1N4004
1N4004
EMI FILTER
D2
C1
D4
1N4004
1N4004
Note: Thick trace on schematic shows high-frequency, high-current path in circuit.
FIGURE 31 — TYPICAL APPLICATION OF THE LX1562 IN AN 80W FLUORESCENT LAMP
½W
2.2M
R1
1%
1µF 250V
29k
R2
1%
Lead lengths must be minimized to avoid high-frequency noise problems.
7T
R3
D5
R10
4.7M
C4
.01µF
BALLAST WITH ACTIVE POWER FACTOR CONTROL
C2
22µF
R4
22k
1N4935
C3
0.1µF
8
V
IN
MULT
IN
3
LX1562
GND
6
I
DET
OUT
COMP
INV
C.S.
1N4148
47
7
R5
R9 620k
2
1 4
D6
5
C5
0.1µF
1/4W
3x
MR854
1M
Q1
1RF730
R6
1.3
D7
1%
11k
1%
V
BOOST
230V
R7
C6 100µF 400V
R8
FLOURESCENT LAMP BALLAST
OUTPUT VOLTAGE REQUIREMENT
Since the converter is a boost type topology, it requires the output voltage to always be higher than the input voltage. It is recommended to select this voltage at least 15% higher than the maximum input voltage in order to: A) Avoid the inductor saturation during line transience, and B) To keep the operating frequency above the audible range at high line.
Figure 32 (next page) shows that when boost voltage is selected near the maximum AC line, the increase in off-time could reduce the operating frequency below the audible frequency and cause inductor humming. In fact, Figure 32 (next page) shows
Copyright © 1996 Rev. 1.3 12/96
that for ±13% (100V to 130V) change in the line voltage the optimum range of the operating frequency is when off-time duty cycle (D') is between 0.57 and 0.75. This means that the boost voltage needs to be 245V when selecting D' = 0.75 at maximum AC line.
In this example, D' is chosen to be 0.8, to slightly reduce the voltage rating of the back end DC to AC fluorescent lamp inverter. This sets the boost voltage at:
130
2
= = 230V
V
O
*
0.8
17
Page 18
LX1562/1563
PRODUCT DATABOOK 1996/1997
S ECOND-GENERATION POWER FACTOR CONTROLLER
RODUCTION DATA SHEET
P
APPLICATION INFORMATION
OUTPUT VOLTAGE REQUIREMENT (continued)
0.2
fn = (1 - D') D'²
0.15
0.1
2 V
D' =
0.05
f = f
) Normalized Operating Frequency
n
(f
0.3
0.4 0.5
AC
V
O
η
VO²
n
4 LP
O
0.6
0.7 0.8 0.9 1.0
(D') Off Time Duty Cycle
FIGURE 32 — NORMALIZED OPERATING FREQUENCY vs.
OFF-TIME DUTY CYCLE
INDUCTOR PEAK CURRENT
It can be shown by referring to Figure 33 that the inductor peak current is always twice the average input current.
Inductor Peak Current Envelope
Average AC Input Current
FIGURE 33 — INDUCTOR CURRENT
I
= AVE [ IL (t) ]
IN(t)
Σ

(IL) (T)
1
I
IN
I
INpeak
I
LP

==
T
= IP =
2

I
LP
2
= Inductor peak current at peak input voltage.
I
L
2
I
L
TONT
OFF
Maximum peak input current can be calculated using:
2P
O
=
I
P
ηV
P
where: η≡Converter efficiency
V
Peak AC input voltage
P
assuming: η = 95%, P
2 x 80
= = 1.2A
I
P
(.95)(141)
I
= 2 * 1.2 = 2.4A
LP/min AC
= 80W, V
O
= 1002 = 141
Pmin
INDUCTOR DESIGN
The inductor value is calculated assuming a 50KHz operating frequency at the nominal AC voltage using the following equation:
VO - V
P
O
O
230 - 1202
230
2
P
4 * 80
V
Output DC voltage
O
Peak AC input voltage
V
P
T Switching period
Output Power
P
O
(1202)
*
2
η T V
= where: η≡Efficiency
L
1
L1 = = 448µH
V
4 P
.95 ( ) 20 * 10-6
choose T = 20µsec (50kHz)
Figure 32 shows that at nominal AC line (D' = 0.74) the normalized frequency is 0.142 and dropping to 0.13 at maximum line condition. This translates to a 10% drop in operating frequency which is still well above the audible range.
Once the inductance is known, we can either use the area product method (AP) or the K for selecting proper core size. In this example, we apply the K
(based on copper losses method),
g
approach using the following steps:
Step 1: Calculate K
=( )
K
g
where: L
g
P
CU
1
Ω≡1.724
using
2
L1I
LP
2
B
Required inductance
-8
10
m
*
B Maximum flux density
Maximum peak inductor current
I
LP
P
Maximum copper dissipation
CU
Assume: P
1.724 * 10
= = 3.21 * 10
K
g
1.6
= 1.6W (2% of total output)
CU
-8

450 * 10
 
-6
0.15
* (2.4)
2
2
-12 m5
g
18
Copyright © 1996
Rev. 1.3 12/96
Page 19
PRODUCT DATABOOK 1996/1997
S ECOND-GENERATION POWER FACTOR CONTROLLER
P RODUCTION DATA SHEET
APPLICATION INFORMATION
LX1562/1563
INDUCTOR DESIGN (continued)
Step 2: Choose a core with higher Kg than the one calculated in
Step 1.
Kg/core = k
AW A
l
2
E
W
where: k Winding coefficient (typ. k=0.4)
A
Bobbin window area
W
Effective core area
A
E
l
Mean length per turn
W
K
factor for TDK PQ2625:
g
= 47.7mm
A
W
AE= 118mm
2
2
lW= 56.2mm
56.2
2
-12 m5
(47.7) (118)
= 0.4 (mm)5 = 4.7 * 10
K
g
Step 3: Determine number of turns.
L I
N =
N = = 61 turns
A
LP
B A
E
450 * 10-6 * 2.4
0.15 * 118 * 10 A
W
= k = 0.4 = 0.31mm
WIRE
N
-6
47.7 61
= 480mil
2
2
choose #22 AWG with r = 0.0165/feet resistance.
R
= N * lw * r
W
R
= 0.185
W
Step 4: Calculate air gap.
µO N2 A
4π
*
L
10
E
-7
(61)
*
450 * 10
2
118*10
*
-6
-6
=
l
g
l
= = 0.122cm = 48 mil
q
CURRENT SENSE RESISTOR
Current sense resistor, R6 is selected using the minimum multi­plier output clamp voltage and the maximum inductor peak current such that:
V
CLAMP(MIN)
R6 = = = 0.45
I
L (MAX)
1.1
2.4
Power dissipation is approximated by:
1
I
P
R
6
1
P
(2.4)
R
6
2
(1 - D'
2 (MAX)
2
(1 - 0.61) = 0.374
), where D'
MIN
MIN
= 1 -
2 V
V
AC(MIN)
BOOST
Select THREE 1.3, ¼W carbon comp resistors in parallel.
MULTIPLIER COMPONENT SELECTION
Calculate R1 & R2 resistor values such that under low line AC input the multiplier output is lower than the minimum clamp voltage.
R2
R1 + R2
2 V
*
AC (MIN)
* K * (V
EA0 (MAX)
- V
REF
) < V
CLAMP (MIN)
where: K Mult. Gain
V
Maximum error amp output where
EA)(MAX)
multiplier is still in linear range. This voltage is 3.5V.
For K = 0.65 & V
R1
> 83
R2
CLAMP (MIN)
= 1.1V, the ratio of R1/R2 is:
Assuming R1 is selected to be:
* R1 = 2.2M (1%)
2.2M
R2 = = 26.4k (1%) select R
83
= 26.7k (1%)
2
* For high input applications such as 277V, R1 must be divided into two resistors in series to meet the maximum rated voltage of the resistors.
To improve THD further (typ. 2-3%), a high value resistor can be connected from the supply voltage to this pin to allow an increase in the switch on-time at the zero crossing by adding an effective offset at the multiplier output.
ERROR AMPLIFIER COMPONENT SELECTION
Boost voltage is programmed with R7 & R8 resistor dividers using the following equation:
R7 R8
V
BOOST
= -1,
V
REF
assuming that the product of R7 and the E.A. input bias current does not cause significant error in the output voltage setting.
ΩΩ
Assuming R7 = 1M
two resistors may be added in series to meet the voltage requirement of the resistor.)
V
(106) (0.5 * 10-6) = 0.5V, which is < 0.25% of the
ERROR
(for output voltage of higher than 250V,
ΩΩ
output voltage.
Calculating R8:
V
BOOST
V
REF
R7
- 1
R8 = = 11k (1%)
Worst case output tolerance is the total of ±3.75% which is the sum of ±1.5% (Ref), ±2% (resistor dividers), and ±0.25% (E.A. input bias current).
Copyright © 1996 Rev. 1.3 12/96
19
Page 20
LX1562/1563
PRODUCT DATABOOK 1996/1997
S ECOND-GENERATION POWER FACTOR CONTROLLER
RODUCTION DATA SHEET
P
APPLICATION INFORMATION
ERROR AMPLIFIER COMPONENT SELECTION (continued)
Capacitor C5 is primarily selected to reject the output ripple associated with twice the line frequency. For a 40dB ripple rejection:
C5 where f
C5 = 0.062µF, Select C5 = 0.1µF
100
2π f
R7
l
2π
120*2.2*10
*
100
= 2x line frequency
l
6
Resistor R9 can be used to improve load transient response at the cost of loosing 1 or 2% of load regulation. The value of this resistor should be much greater than R8:
R9 = 620k
One way of achieving desired load transient response without resorting to a complex mathematical model of the converter, is to dynamically switch the output load and empirically find the compensation network. The value of resistor R9 is selected using the method shown in Figure 34.
V
BOOST
Min.
R
L
10Hz
50% D.C.
FIGURE 34 — LOAD TRANSIENT RESPONSE CIRCUIT
I
COMPONENT SELECTION
DETECT
Load
Figure 35 shows voltage envelope generated by flyback voltage across I
Select turns ratio n such that,
n =
n = = 0.11
I selected to be 7T.
winding:
DET
5V
- 2 V
V
BOOST
5V
230 - 2
winding turns are
DET
*
130
AC (MAX)
(V
- VAC)
n
BOOST
V
n
AC
FIGURE 35 — FLYBACK VOLTAGE
ACROSS I
WINDING
DET
and R4 resistor:
n * V
BOOST
< R4 < 500k
-3
3 * 10
0.11 * 230 3 * 10
< R4 < 500k, or 8.4k < R4 < 500k
-3
Select R4 = 22k
SUPPLY VOLTAGE
Resistor R3 must be selected such that it ensures converter start­up at low line and is rated for high line power dissipation.
2 V
R3 < where: I
R3 < = 466k
R3 > 4 V
AC (MIN)
I
ST (MAX)
2
100
*
0.3 * 10
-3
(to keep power dissipation below 0.5W)
AC (MAX)
Maximum start-up
ST
V
ST
T
ST(MAX)
current
Start-up voltageMaximum start-up
time at AC power-on
R3 > 68k , select R3 = 120k.
Start-up time of converter is given by:
V
T
ST (MAX)
C2
2 V
AC (MIN)
R3
ST
- I
ST
for our application this will be 25ms/µF.
The start-up capacitor is selected such that capacitor discharge time is always longer than the time it takes for the bootstrap voltage to reach above the minimum start-up threshold of the IC.
I
* t
C3 < where: I
OP
V
MIN
Maximum dynamic
OP
supply current of the IC
t Rise time of the
bootstrap voltage
Minimum hysteresis
V
MIN
10 * 10-3 * 10 * 10
C3 < = 29µF
4
-3
(4V for 1562,
voltage
1.7V for 1563)
Select C3 = 33µF.
Start-up time is approximately 0.8 seconds.
The auxiliary winding turns are selected such that it provides 15V of operating voltage.
V
N
N
S
S
* = 61 * = 4T
P
V
O
However, in this example I which eliminates the need for a third winding. This is possible
V
S
V
O
winding is used to power the IC
DETECT
since the internal clamping of the output drive limits the gate drive voltage to 14V (typ.) if the supply voltage exceeds this limit.
20
Copyright © 1996
Rev. 1.3 12/96
Page 21
PRODUCT DATABOOK 1996/1997
S ECOND-GENERATION POWER FACTOR CONTROLLER
P RODUCTION DATA SHEET
APPLICATION INFORMATION
POWER MOSFET SELECTION
The voltage rating of MOSFET and rectifier must be higher than the maximum value of the output voltage.
1.2 V
V
DS
O MAX
The RMS current can be approximated by multiplying the RMS current at the peak of the line by 0.7.
I
= 0.7 I
RMS
D = 0.39 at V I
= (0.7)(2.4)(.39/3) = 0.61A
I
RMS
R
P
D/3 D On-time duty cycle
LP
= 2.4A
LP
DS
allowable power I
DC
AC
P
DC
2
I
RMS
dissipation.
1
= 1.6
R
DS
0.61
IRF730 with R
requirements.
DS
= 1
INPUT RECTIFIER AND CAPACITOR SELECTION
The current through each diode is a half-wave rectified sine wave. The maximum current happens at minimum line with a peak value of 1.2A.
I
I
PEAK
= = = 0.38A
AVE
π
choose 1N4004 with 1A rating.
= (I
P
DISS
= TA + P
T
J
T
= 80 + (.344)(65) = 102°C
J
) (VF) = 0.38 x 0.9 = 0.344W
AVE
x θ
D
JA
= 100V
ΩΩ
and V
ΩΩ
1.2
π
V
282V
DS
RMS
= 400V meets the above
DS
assuming θ lead length.
= 65°C/W for 1/8"
JA
I
LP
D
/triangle = I
D/3
LP
LX1562/1563
Assuming ϕ is the percentage of allowable input current ripple, C1 can be calculated using the following equations:
2 P
R
EFF
C1 f
if ϕ = 3%
R
EFF
C1 = 0.9µF
choose 1µF, 250V capacitor.
OUTPUT CAPACITOR SELECTION
There are mainly two criteria for selecting the output capacitor: A large enough capacitance to maintain a low ripple voltage, and a low ESR value in order to prevent high power dissipation due to RMS currents.
The output capacitance can be approximated from the following equation:
C6 where: I
I
DC
assuming 5% peak to peak ripple, C6 = 81µF
choose C6 = 100µF.
O
=
2
η I
P
1
ϕ 2π R
EFF fSW
2 x 80
= = 117
(.95)(1.2)
2
1
(.03)(2π)(117)(50000)
I
DC
2π f
V
LINE
80
= = 0.348A
230
0.348
2π (60) (11.5)
Switching frequency
SW
of inductor current at peak input voltage.
DC output current
DC
DV Output ripple
Copyright © 1996 Rev. 1.3 12/96
21
Page 22
LX1562/1563
PRODUCT DATABOOK 1996/1997
S ECOND-GENERATION POWER FACTOR CONTROLLER
RODUCTION DATA SHEET
P
TYPICAL APPLICATIONS
120V
450µH
L1
61T
#22AWG
D7
V
BOOST
R3
D3
D1
AC+
AC-
120V
AC
R1
C1
R2
D2 D4
Note: Thick trace on schematic shows high-frequency, high-current path in circuit. Lead lengths
must be minimized to avoid high-frequency noise problems.
FIGURE 36 — TYPICAL APPLICATION OF THE LX1562 IN AN 80W
FLUORESCENT LAMP BALLAST WITH ACTIVE POWER FACTOR CONTROL.
Electrical Specifica­tion
Ref. Component Manuf.
120VAC Input — 230VDC / 80W Output
7T
D5
C4
#26AWG
R4
C2
R10
3
C3
IC LX1562 Linfinity L1 PQ2625/H7C1 Core TDK Q1 IRF730, 400V, 1 rds I.R. D1-D4 IN4004 1A, 400V Motorola D5 1N4935 1A Motorola D6 1N4148
(improves Q1 power dissipation)
Motorola
D7 MR854, 3A, 400V Motorola R1 2.2M, ±1% R2 26.7k, ±1% R3 100k, ½W R4 22k R5 47 R6 1.5, Carbon type (3X) R7 1MΩ, 1% R8 11k, 1% R9 620k
(improves load transient response)
R10 4.7M
A complete evaluation board is available from Linfinity Microelectronics Inc.
MULT
IN
8
V
IN
5
I
DET
D6
R7
R5
OUT
COMP
LX1562
INV
GND
C.S.
6
7
R9
2
C5
1 4
Q1
C6
R8
R6
Ref. Component Manuf.
C1 QXF2E105KRPT
1µF/250V - Plastic Film (high freq.) Nichicon C2 22µF/35V - Electrolytic C3 0.1µF/50V - Ceramic C4 0.01µF/50V - Ceramic C5 0.1µF/50V - Ceramic C6 LGQ2G101MHS A/Z* Nichicon
100µF/400V - Electrolytic
* A = 25mm diam.
Z = 22mm diam.
FLOURESCENT LAMP BALLAST
22
Copyright © 1996
Rev. 1.3 12/96
Page 23
A
C+
AC-
220V
AC
D1
D3
D2 D4
PRODUCT DATABOOK 1996/1997
S ECOND-GENERATION POWER FACTOR CONTROLLER
P RODUCTION DATA SHEET
TYPICAL APPLICATIONS
220V
L1
1.2mH
C1
R3
80T
7T
4T
R1
R2
C4
R10
C2
#24AWG #26AWG #26AWG
D5
3
C3
MULT
IN
V
R4
8
IN
GND
6
5
I
DET
OUT
COMP
LX1562
INV C.S.
D6
7
2
1
4
R5
R9
C5
Q1
R6
LX1562/1563
D7
R7
R8
V
BOOST
C6
FLOURESCENT LAMP BALLAST
Note: Thick trace on schematic shows high-frequency, high-current path in circuit. Lead lengths
must be minimized to avoid high-frequency noise problems.
FIGURE 37 — TYPICAL APPLICATION OF THE LX1562 IN AN 80W
FLUORESCENT LAMP BALLAST WITH ACTIVE POWER FACTOR CONTROL.
Electrical Specifica­tion
Ref. Component Manuf.
IC LX1562 Linfinity L1 PQ2625/H7C1 Core TDK Q1 IRF830, 500V, 1.5 rds I.R. D1-D4 IN4007 1A, 1000V Motorola D5 1N4935 1A Motorola D6 1N4148 D7 MR856, 3A, 600V Motorola R1 2.2M, ±1% R2 12k, ±1% R3 220k, ½W R4 22k
220VAC Input — 400VDC / 80W Output
Ref. Component Manuf.
C1 QXF2J224KRPT
0.22µF/630V - Plastic Film Nichicon C2 22µF/35V - Electrolytic C3 0.1µF/50V - Ceramic C4 0.01µF/50V - Ceramic
(improves Q1 power dissipation)
Motorola
C5 0.1µF/50V - Ceramic C6* LGQ2W680MHS A/Z* Nichicon
68µF/450V - Electrolytic
* A = 25mm diam. Z = 22mm diam.
R5 47 R6 1.8, Carbon type (2X) R7 1MΩ, 1% R8 6.19k, 1% R9 620k
(improves load transient response)
R10 2.7M
A complete evaluation board is available from Linfinity Microelectronics Inc.
Copyright © 1996 Rev. 1.3 12/96
23
Page 24
LX1562/1563
V
IN
I
DET
OUT
COMP
INV
C.S.
GND
MULT
LX1562
Q1
V
BOOST
FLOURESCENT LAMP BALLAST
IN
5
8
7
2
1
4
6
3
277V
AC
R4
R3
R1
C1
R2
C4
D5
C2
R5
C5
R7
A
C6
A
D7
R8
R9
R6
D6
AC+
AC-
D1
L1
2.2mH
15T
D3
D2 D4
C3
#24AWG #26AWG
80T
#26AWG
3T
R10
R7
B
C6
B
PRODUCT DATABOOK 1996/1997
S ECOND-GENERATION POWER FACTOR CONTROLLER
RODUCTION DATA SHEET
P
TYPICAL APPLICATIONS
277V
24
Note: Thick trace on schematic shows high-frequency, high-current path in circuit. Lead lengths
must be minimized to avoid high-frequency noise problems.
FIGURE 38 — TYPICAL APPLICATION OF THE LX1562 IN AN 80W
FLUORESCENT LAMP BALLAST WITH ACTIVE POWER FACTOR CONTROL.
Electrical Specifica­tion
Ref. Component Manuf.
IC LX1562 Linfinity L1 PQ2625/H7C1 Core TDK Q1 IRF830, 500V, 1.5 rds I.R. D1-D4 IN4007 1A, 1000V Motorola D5 1N4935 1A Motorola D6 1N4148
277VAC Input — 480VDC / 80W Output
(improves Q1 power dissipation)
Motorola
D7 MR856, 3A, 600V Motorola R1 2.2M, ±1% R2 10k, ±1% R3 390k, ½W R4 22k R5 47 R6 2.2, Carbon type (2X) R7 499k, 1% (2X) R8 5.23k, 1% R9 620k R10 2.2M
(improves load transient response)
A complete evaluation board is available from Linfinity Microelectronics Inc.
Ref. Component Manuf.
C1 QXF2J224KRPT
C2 22µF/35V - Electrolytic C3 0.1µF/50V - Ceramic C4 0.01µF/50V - Ceramic C5 0.22µF/50V - Ceramic C6 UVZ2F470MEH (2X) Nichicon
0.22µF/630V - Plastic Film Nichicon
47µF/315V - Electrolytic
Copyright © 1996
Rev. 1.3 12/96
Page 25
PRODUCT DATABOOK 1996/1997
A
S ECOND-GENERATION POWER FACTOR CONTROLLER
P RODUCTION DATA SHEET
TYPICAL APPLICATIONS
LX1562/1563
C+
90-265V
AC
AC-
#24AWG #26AWG #26AWG
D5
90V - 265V
R4
8
V
IN
5
I
DET
D6
D1
D3
R3
R1
62T
7T
L1
450µH
3T
C2
R5
C1
OUT
7
R9
MULT
IN
3
R2
D2 D4
Note: Thick trace on schematic shows high-frequency, high-current path in circuit. Lead lengths
must be minimized to avoid high-frequency noise problems.
C4
C3
LX1562
GND
6
COMP
INV
C.S.
2
C5
1 4
Q1
R6
D7
R7
R8
V
BOOST
C6
FLOURESCENT LAMP BALLAST
FIGURE 39 — TYPICAL APPLICATION OF THE LX1562 IN AN 80W
FLUORESCENT LAMP BALLAST WITH ACTIVE POWER FACTOR CONTROL.
Electrical Specifica­tion
Ref. Component Manuf.
IC LX1562 Linfinity L1 PQ2625/H7C1 Core TDK Q1 IRF840, 500V, 1 rds I.R. D1-D4 IN4007 1A, 1000V Motorola D5 1N4935 1A Motorola D6 1N4148 D7 MR856, 3A, 600V Motorola R1 2.2M, ±1% R2 16.3k, ±1% R3 130k, ½W R4 22k
90-265VAC Input — 400VDC / 80W Output
Ref. Component Manuf.
C1 QXF2J224KRPT
0.47µF/630V - Plastic Film Nichicon C2 22µF/35V - Electrolytic C3 0.1µF/50V - Ceramic C4 0.01µF/50V - Ceramic
(improves Q1 power dissipation)
Motorola
C5 0.33µF/50V - Ceramic C6* LGQ2W680MHS A/Z* Nichicon
68µF/450V - Electrolytic
* A = 25mm diam. Z = 22mm diam.
R5 47 R6 1, Carbon type (4X) R7 1MΩ, 1% R8 6.19k, 1% R9 620k
(improves load transient response)
A complete evaluation board is available from Linfinity Microelectronics Inc.
Copyright © 1996 Rev. 1.3 12/96
25
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