-600/+800mA TOTEM POLE GATE DRIVER WITH
UVLO PULL-DOWN AND VOLTAGE CLAMP
■ DIP-8/SO-8 PACKAGES
1.1 APPLICATIONS
■ PFC PRE-REGULATORS FOR:
– IEC61000-3-2 COMPLIANT SMPS (TV,
Figure 2. Block Diagram
1
INV
VOLTAGE
REGULATOR
-
+
2.5V
OVERVOLTAGE
DETECTION
gure 1. Packages
DIP-8
SO-8
Table 1. Order Codes
Part NumberPackage
L6562NDIP-8
L6562DSO-8
L6562DTRTape & Reel
DESKTOP PC, MONITOR) UP TO 300W
– HI-END AC-DC ADAPTER/CHARGER
– ENTRY LEVEL SERVER & WEB SERVER
2DESCRIPTION
The L6562 is a current-mode PFC controller operating in Transition Mode (TM). Pin-to-pin compatible with the predecessor L6561, it offers improved
performance.
COMPMULTCS
234
MULTIPLIER AND
THD OPTIMIZER
+
-
5pF
40K
CC
V
June 2004
8
CC
V
25 V
R2
6
2.1 V
1.6 V
GND
R1
INTERNAL
SUPPLY 7V
REF2
V
DRIVER
15 V
7
GD
RSQ
+
UVLO
-
ZERO CURRENT
DETECTOR
+
-
5
ZCD
DISABLE
Starter
stop
STARTER
REV. 6
1/16
L6562
2 DESCRIPTION (continued)
The highly linear multiplier includes a special circuit, able to reduce AC input current distortion, that allows
wide-range-mains operation with an extremely low THD, even over a large load range.
The output voltage is contr olled by means of a voltage-mode er ror amplifier and a precise (1% @Tj =
25°C) internal voltage reference.
The device features extremely low consumption (≤70 µA before start-up and <4 mA running) and includes
a disable function s uitable for IC remo te ON/OFF, which makes it easier t o comply with energ y saving
norms (Blue Angel, EnergyStar, Energy2000, etc.).
An effective two-step OVP enab les to sa fely han dle overvol tages either occ urring at start-up or re sulti ng
from load disconnection.
The totem-pole output stage, capable of 600 mA source and 800 mA sink current, is suitable for big MOSFET or IGBT drive which, combined with the other features, makes the device an excellent low-cost solution for EN61000-3-2 compliant SMPS's up to 300W.
Table 2. Absolute Maximum Ratings
SymbolPinParameterValueUnit
V
CC
IGD7Output Totem Pole Peak Current±0.8A
---1 to 4Analog Inputs & Outputs-0.3 to 8V
IZCD5Zero Current Detector Max. Curre nt-50 (source)
P
tot
T
j
T
stg
8IC Supply voltage (Icc = 20 mA)self-limitedV
10 (sink)
Power Dissipation @Tamb = 50°C (DIP-8)
(SO-8)
Junction Temperature Operating range-40 to 150°C
Storage Temperature-55 to 150°C
1INVInverting input of the error amplifier. The information on the output voltage of the PFC pre-
regulator is fed into the pin through a resistor divider.
2COMPOutput of the erro r amplifier. A compensation ne twork is placed be tween this pin and INV (pin
#1) to achieve stability of the voltage control loop and ensure high power factor and low THD.
3MULTMain input to the multiplier. This pin is connected to the rect ified mains voltage via a resistor
divider and provides the sinusoidal reference to the current loop.
4CSInpu t to th e PW M co mparato r. The current fl owing in the M OSFE T is s ense d thro ugh a resis tor,
the resulting voltage is applied to this pin and compared with an internal sinusoidal-shaped
reference, generated by the multiplier, to determine MOSFET’s turn-off.
5ZCDBoost inductor’s demagnetization sensing input for transition-mode operation. A negative-going
edge triggers MOSFET’s turn-on.
6GNDGround. Current return for both the signal part of the IC and the gate driver.
7GDG ate driver output. The to tem pole output stag e is able to drive power MOSFET’s and IGBT’s
with a peak current of 60 0 mA source and 800 mA sink. The high-level voltage of this pin is
clamped at abou t 12V to avoid excessive gate voltages in case the pin is supplied with a high
Vcc.
8VccSupply Voltage of both the signal par t of the IC and the gate dr iver. The supply voltage upper
limit is extended to 22V min. to provide more he ad roo m for supply voltage cha ng es.
L6562
Table 5. Electrical Characteristics
(T
= -25 to 125°C, VCC = 12, CO = 1 nF; unless otherwise specified)
j
SymbolParameterTest ConditionMin. Typ.Max.Unit
SUPPLY VOLTAGE
V
V
CCon
V
CCOff
HysHysteresis2.22.8V
V
SUPPLY CURRENT
I
start-up
I
MULTIPLIER INPUT
I
MULT
V
MULT
VCS∆
---------------------
∆
V
MULT
ERROR AMPLIFIER
V
I
Operating rangeAfter turn-on10.322V
CC
Turn-on threshold
Turn-off threshold
Zener VoltageICC = 20 mA222528V
Z
(1)
(1)
111213V
8.79.510.3V
Start-up CurrentBefore turn-on, VCC =11V4070µ A
I
Quiescent CurrentAfter turn-on2.53.75mA
q
Operating Supply Current@ 70 kHz3.55mA
CC
I
Quiescent CurrentDuring OVP (either static or
q
Input Bias CurrentV
dynamic) or V
= 0 to 4 V-1µA
VFF
=150 mV
ZCD
Linear Operation Range0 to 3V
Output Max. SlopeV
K
INV
(2)
Gain
Voltage Feedback Input
Threshold
MULT
V
COMP
V
MULT
= 0 to 0.5V
= 1 V, V
= Upper clamp
= 4 V0.50.60.71/V
COMP
1.651.9V/V
Tj = 25 °C2.4652.52.535V
10.3 V < Vcc < 22 V
(1)
2.442.56
Line RegulationVcc = 10.3 V to 22V25mV
Input Bias CurrentV
INV
= 0 to 3 V-1µA
INV
2.2mA
3/16
L6562
Table 5. Electrical Characteristics (continu ed)
= -25 to 125°C, VCC = 12, CO = 1 nF; unless otherwise specified)
(T
j
SymbolParameterTest ConditionMin. Typ.Max.Unit
G
GBGain-Bandwidth Product1MHz
I
COMP
V
COMP
CURRENT SENSE COMPARATOR
I
t
d(H-L)
V
CS clamp
V
CSoffset
ZERO CURRENT DETECTOR
V
ZCDH
V
ZCDL
V
ZCDA
V
ZCDT
I
ZCDb
I
ZCDsrc
I
ZCDsnk
V
ZCDdis
V
ZCDen
I
ZCDres
STARTER
t
START
OUTPUT OVERVOLTAGE
I
OVP
HysHysteresis
GATE DRIVER
V
V
V
Oclamp
(1) All param eters are in tr acking
(2) The multipl i er output is given by:
(3) Parameters guaranteed by design, functionality tested in production.
Voltage GainOpen loop6080dB
v
Source CurrentV
Sink CurrentV
Upper Clamp VoltageI
Lower Clamp Voltage
Input Bias CurrentVCS = 0-1µA
CS
Delay to Output
Current sense reference clampV
Current sense offsetV
Upper Clamp VoltageI
Lower Clamp VoltageI
Arming Voltage
COMP
COMP
SOURCE
I
= 0.5 mA
SINK
= 4V, V
= 4V, V
= 0.5 mA5.35.76V
= 2.4 V-2-3.5-5mA
INV
= 2.6 V2.54.5mA
INV
(1)
2.12.252.4V
200350ns
= Upper clamp1.61.71.8V
COMP
= 030mV
MULT
V
= 2.5V5
MULT
= 2.5 mA5.05.76.5V
ZCD
= -2.5 mA0.30.651V
ZCD
(3)
2.1V
(positive-going edge)
Triggering Voltage
(3)
1.6V
(negative-going edge)
Input Bias Current
= 1 to 4.5 V
V
ZCD
2µA
Source Current Capability-2.5-5.5mA
Sink Current Capability2.5mA
Disable threshold15020025 0mV
Restart threshold350mV
Restart Current after Disable3075µA
Start Timer period
75130300µs
Dynamic OVP triggering current354045µA
(3)
Static OVP threshold
OH
Dropout Voltage
OL
Voltage Fall Time3070ns
t
f
t
Voltage Rise Time4080ns
r
Output clamp voltageI
UVLO saturationV
VcsKV
(1)
I
GDsource
I
GDsource
I
= 200 mA
GDsink
GDsource
= 0 to V
CC
MULTVCOMP
= 20 mA
= 200 mA
= 5mA; Vcc = 20V
, I
CCon
2.5–()⋅⋅=
=10mA1.1V
sink
2.12.252.4V
101215V
30µA
22.6
2.53V
0.91.9V
4/16
3TYPICAL ELECTRICAL CHARACTERISTICS
L6562
Figure 4. Supply current vs. Supply voltage
I
CC
(mA)
10
5
1
0.5
0.1
0.05
0.01
0.005
0
05101520
V
cc(V)
Figure 5. Start-up & UVLO vs. T
12.5
V
CC-ON
12
(V)
Co = 1nF
f = 70 kHz
= 25°C
T
j
j
25
Figure 6. IC consumption vs. T
Icc
10
[mA]
5
j
2
1
0.5
Vcc = 12 V
Co = 1 nF
f = 70 kHz
0.2
0.1
0.05
0.02
-50050100150
Before start-up
Tj (°C)
Figure 7. Vcc Zener voltage vs. Tj
Vcc
Z
28
(V)
27
Operating
Quiescent
Disabled or
during OVP
CC-OFF
V
(V)
11.5
11
10.5
10
9.5
9
-50050100150
Tj (
°C)
26
25
24
23
22
-50050100150
Tj (°C)
5/16
L6562
Figure 8. Feedback reference vs. Tj
V
REF
2.6
(V)
2.55
2.5
2.45
2.4
-50050100150
Tj (°C)
Figure 9. OVP current vs. T
I
OVP
41
(µA)
40.5
40
39.5
39
-50050100150
Tj (°C)
j
Vcc = 12 V
Vcc = 12 V
Figure 11. Delay-to-output vs. T
t
D(H-L)
500
(ns)
400
300
200
100
0
-50050100150
Tj (°C)
j
Figure 12. Multiplier characteristic
V
(pin 4)
CS
upper voltage
(V)
clamp
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
5.0
4
5
.
4.0
V
MULT
(pin 3) (V)
Vcc = 12 V
V
COMP
(V)
3.5
3.2
3.0
2.8
2.6
(pin 2)
Figure 10. E/A output clamp levels vs. T
Vpin2
6
(V)
6/16
Upper clamp
5
4
3
Lower clamp
2
-50050100150
Tj (°C)
Vcc = 12 V
j
Figure 13. Multiplier gain vs. T
K
1
0.8
j
Vcc = 12 V
=4 V
V
COMP
V
=1V
MULT
0.6
0.4
0.2
0
-50050100150
Tj (°C)
L6562
Figure 14. Vcs clamp vs. Tj
V
CSx
2
(V)
1.8
1.6
1.4
Vcc = 12 V
V
1.2
COMP = Upper clamp
1
-50050100150
Tj (°C)
Figure 15. Start-up timer vs. T
Tstart
150
(µs)
140
130
Vcc = 12 V
Figure 17. ZCD source capability vs. T
I
ZCDsrc
0
(mA)
-2
-4
-6
-8
-50050100150
Tj (°C)
j
Figure 18. Gate-drive output low saturation
pin7
V
[V]
4
Tj = 25 °C
Vcc = 11 V
SINK
Vcc = 12 V
= lower clamp
V
ZCD
j
3
120
110
100
-50050100150
Tj (°C)
Figure 16. ZCD clamp levels vs. T
V
ZCD
7
(V)
6
5
4
3
2
1
0
-50050100150
Tj (°C)
Upper clamp
I
ZCD = ±2.5 mA
Lower clamp
j
Vcc = 12 V
2
1
0
02004006008001,000
IGD[mA]
Figure 19. Gate-drive output high saturation
pin7
V
[V]
-1.5
Tj = 25 °C
Vcc - 2.0
-2.5
Vcc - 2.5
Vcc - 3.0
-3.5
Vcc - 3 .5
Vcc - 4.0
-4.5
-2
-3
-4
0100 200300 400500 600700
IGD[mA]
Vcc = 11 V
SOURCE
7/16
L6562
Figure 20. Gate-drive clamp vs. T
clamp
Vpin7
15
(V)
14
13
12
11
10
-50050100150
Tj (°C)
j
Vcc = 20 V
Figure 21. UVLO saturation vs. T
Vpin7
1.1
(V)
1
0.9
0.8
0.7
0.6
0.5
-50050100150
Tj (°C)
j
Vcc = 0 V
4APPLICATION INFORMATION
4.1 Overvoltage protection
Under steady-state conditions, the voltage control loop keeps the output voltage Vo of a PFC pre-regulator
close to its nomina l v al ue, se t by th e r esi sto rs R1 an d R2 of the outp ut d iv id er. Neglecting ripple co mponents, the current through R1, I
the error amplifier is internally referenced at 2.5V, also the voltage at pin INV will be 2.5V, then:
, equals that through R2, IR2. Considering that the non-inverting input of
R1
I
R2
2.5
------- -I
R2
R1
Vo 2.5–
--------------------- -===
R1
.
If the output voltage experiences an abrupt change ∆Vo > 0 due to a load drop, the voltage at pin INV will
be kept at 2.5V by the loc al feedback of the error amplifier, a network co nnected be tween pins INV a nd
COMP that introduces a long time constant to achieve high PF (this is why ∆Vo can be large). As a result,
the current through R2 will remain equal to 2.5/R2 but that through R1 will become:
R1
Vo 2.5–Vo∆+
--------------------------------------- -=
R1
.
I'
The difference current ∆IR1=I'R1-IR2=I'R1-IR1=∆Vo/R1 will flow through the compensation network and enter the error amplifier output (pin COMP). This current is monitored inside the L6562 and if it reaches about
37 µA the output voltage of the mul tip li er is forced to dec reas e, th us smo othly red ucing the en er gy deliv ered to the output. As the curren t excee ds 40 µA , the O VP is triggered (Dynamic OVP): the ga te- dri ve is
forced low to switch off the external power transistor and the IC put in an idle state. This condition is maintained until the c urrent falls b elow ap prox imatel y 10 µA , w hich re -enab les the in ternal s tarte r and al lows
switching to restart. The output ∆Vo that is able to trigger the Dynamic OVP function is then:
Vo∆R1 40 10
⋅⋅=
6–
.
An important advan tage of thi s technique is that th e OV le vel can be s et indepe ndently of the regu lated
output voltage: the latter depends on the ratio of R1 to R2, the former on the individual value of R1. Another
advantage is the precision: the tol erance of the detectio n current is 12%, that is 12% tolerance on ∆Vo.
Since ∆Vo << Vo, the tolerance on the absolute value will be proportionally reduced.
Example: Vo = 400 V, ∆Vo = 40 V. Then: R1=4 0V /40 µA=1MΩ; R2=1MΩ·2.5/(400-2.5)=6.289kΩ. The tolerance on the OVP level due to the L6562 will be 40·0.12=4.8V, that is 1.2% of the regulated value.
8/16
L6562
When the load of a PFC pre-regulator is very low, the output voltage tends to stay steadily above the nominal value, which cannot be handled by the Dynamic OVP. If this occurs, however, the error amplifier output will saturate low; hence, when this is detected, the external power transistor is switched off and the IC
put in an idle state (Static OVP). Normal operation is resumed as the error amplifier goes back into its linear region. As a result, the L6562 will work in burst-mode, with a repetition rate that can be very low.
When either OVP is activa ted the quies cent co nsump tion of the IC is redu ced to minim ize the dischar ge
of the Vcc capacitor and increase the hold-up capability of the IC supply system.
4.2 THD optimizer circuit
The L6562 is equipped with a special circuit that reduces the conduction dead-angle occurring to the AC
input current near the zero-crossings of the line voltage (crossover distortion). In this way the THD (Total
Harmonic Distortion) of the current is considerably reduced.
A major cause of this distortion is the inability of the system to transfer energy effectively when the instantaneous line voltage is very low. This effect is magnified by the high-frequency filter capacitor placed after
the bridge rectifier, which retains some residual voltage that causes the diodes of the bridge rectifier to be
reverse-biased and the input current flow to temporarily stop.
Figure 22. THD optimization: standard TM PFC controller (left side) and L6562 (right side)
Input currentInput current
Rectified mains voltageRectified mains voltage
Imains
Input current
MOSFET's drain voltage
Vdrain
Imains
Input current
MOSFET's drain voltage
Vdrain
To overcome this issue the ci r cu it emb edd ed in the L656 2 for ce s the PF C pre-r eg ula tor to pr oc ess more
energy near the line voltage zero-crossings as compared to that commanded by the control loop. This will
result in both minimizin g the tim e int er val wher e en ergy tran sfe r is lack in g and ful ly dis c hargi ng the high frequency filter capacito r after the bridge. The effect of the circuit is show n in figure 23, where the key
waveforms of a standard TM PFC controller are compared to those of the L6562.
Essentially, the circuit artificially increases the ON-time of the power switch with a positive offset added to
9/16
L6562
the output of the multiplier in the proximity of the line voltage zero-crossings. This offset is reduced as the
instantaneous line vol tage inc reases , so that it becomes neglig ible as the l ine vol tage mo ves towa rd the
top of the sinusoid.
To maximally benefit from the THD optimizer circuit, the high-frequency filter capacitor after the bridge rectifier should be minimi zed, comp atibly with EM I filter ing nee ds. A la rge capac itanc e, in fact, i ntrodu ces a
conduction dead-angle of the AC input current in itself - even with an ideal energy transfer by the PFC preregulator - thus making the action of the optimizer circuit little effective.
Note: (1) Dimensi ons D does not inclu de mold flash, pro tru-
mminch
MIN.TYP. MAX.MIN.TYP. MAX.
4.805.000.1890.197
sions or gate bur rs.
Mold flash , pot rus ions or ga t e burr s shall not exce ed
0.15mm (.006inch) in total (both side).
OUTLINE AND
MECHANICAL DA T A
SO-8
14/16
0016023 C
Table 9. Revision History
DateRevisionDescription of Chan g es
January 20045First Issue
L6562
June 20046Modified the Style-look in compliance with the “Corporate Technical
Publications Design Guide ”.
Changed input of the power amplifier connected to Multiplier (Fig. 2).
15/16
L6562
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