Datasheet HT82P604B Datasheet (Holtek Semiconductor Inc)

HT82P604B
Preliminary

Features

Operating voltage: 5V~12V
·
·
Simple single-loop control design
·
-
Voltage-mode PWM control
Fast transient response
·
-
High-bandwidth error amplifier
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Full 0% to 100% duty ratio
Excellent output voltage regulation
·
-
±1% over line voltage and temperature

Applications

Power supply for PentiumTM, Pentium
·
Pro, PowerPCTMand AlphaTMMicroproces sors

General Description

The HT82P604B provides complete control and protection for a DC-DC converter optimized for high performance microprocessor applications. It is designed to drive two N-Channel MOSFETs in a synchronous-rectified buck to­pology. The HT82P604B integrates all of the control, output adjustment, monitoring and protection functions into a single package.
The output voltage of the converter is easily ad­justed and precisely regulated. The HT82P604B includes a 5-input digital-to-analog converter (DAC) that adjusts theoutput voltage from 2.1V to 3.5V in 0.1V increments and from 1.3V to
2.05V in 0.05V steps. The precision reference and voltage-mode regulator hold the selected output voltage to within ±1% over temperature andlinevoltagevariations.
The HT82P604B provides simple, single feed back loop, voltage-mode control with fast tran
TM
DC-DC Converter
5 bit digital-to-analog output voltage selection
·
-
Wide range -1.3V to 3.5V
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0.1V binary steps from 2.1V to 3.5V
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0.05V binary steps from 1.3V to 2.05V
Power-good output voltage monitor
·
Over-voltage and over-current sensing ele
·
ment, uses MOSFET¢sr Small converter size
·
-
Constant frequency operation
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200kHz free-running oscillator program mable from 50kHz to over 1MHz
High-power5Vto3.xVDC-DCregulators
·
-
Low-voltage distributed power supplies
·
sient response. It includes a 200kHz free-running triangle-wave oscillator that is adjustable from below 50kHz to over 1MHz. The error amplifier features a 15MHz gain-bandwidth product and 6V/ms slew rate which enables high converter bandwidth for fast transient performance. The resulting PWM duty ratio ranges from 0% to 100%.
The HT82P604B monitors the output voltage with a window comparator that tracks the DAC output and issues a Power Good signal when the output is within ±10%. The HT82P604B protects against over-current conditions by in hibiting PWM operation. Built-in over-voltage protection triggers an external SCR to crowbar the input supply. The HT82P604B monitors the current by using the r MOSFET which eliminates the need for a cur
­rent sensing resistor.
-
DS (ON)
DS (ON)
-
-
-
of the upper
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Pentium is a trademark of Intel Corporation
1 March 23, 2000
Preliminary

Pin Assignment

20
VSEN
OCSET
COM P
SS
VID0
VID1
VID2
VID3
VID4
FB
1
2
3
4
5
6
7
8
9
10
H T82P 604B
20 S O P

Pin Description

Pin No. Pin Name I/O Description
1 VSEN I
2 OCSET I
3SS O
4~8 VID0~4 I
9, 10 COMP, FB I
11 GND P
RT
19
OVP
VCC
18
17
LG A TE
16
PGND
BOO T
15
14
UGATE
PHASE
13
PGOOD
12
GND
11
This pin is connected to the converters output voltage. The PGOOD and OVP comparator circuits use this signal to report output voltage status and for overvoltage protection.
Connect a resistor (R per MOSFET. R (I
), and the upper MOSFET on-resistance (r
OCS
OCSET
) from this pin to the drain of the up
OCSET
, an internal 200mA current source
converter over-current (OC) trip point.
IR
´
I=
PEAK
OCS OCSET
r
DS(ON)
An over-current trip cycles the soft-start function.
Connect a capacitor from this pin to ground. This capacitor, along with an internal 10mA current source, sets the soft-start interval of the converter.
VID0-4 are the input pins to the 5-bit DAC. The states of these five pins program the internal voltage reference (DACOUT). The level of DACOUT sets the converter output voltage. It also sets the PGOOD and OVP thresholds. Table 1 specifies DACOUT for the 32 combinations of DAC inputs.
COMP and FB are the available external pins of the error ampli fier. The FB pin is the inverting input of the error amplifier and the COMP pin is the error amplifier output. These pins are used to compensate the voltage-control feedback loop of the con verter.
Signal ground for the IC. All voltage levels are measured with respect to this pin.
HT82P604B
) set the
DS (ON)
-
-
-
2 March 23, 2000
Preliminary
Pin No. Pin Name I/O Description
PGOOD is an open collector output used to indicate the status of the converter output voltage. This pin is pulled low when the
12 PGOOD O
13 PHASE O
14 UGATE O
15 BOOT I
16 PGND P
17 LGATE O
18 VCC P Provide a 12V bias supply for the chip to this pin.
19 OVP O
20 RT I
converter output is not within ±10% of the DACOUT reference voltage. Exception to this behavivor is the ¢11111¢ VID pin com bination which disables the converter; in this case, PGOOD as serts a high level.
Connect the PHASE pin to the upper MOSFET source. This pin is used to monitor the voltage drop across the MOSFET for over-current protection. This pin also provides the return path for the upper gate drive.
Connect UGATE to the upper MOSFET gate. This pin provides the gate drive for the upper MOSFET.
This pin provides bias voltage to the upper MOSFET driver. A bootstrap circuit may be used to create a BOOT voltage suitable to drive a standard N-Channel MOSFET.
This is the power ground connection. Tie the lower MOSFET source to this pin.
Connect LGATE to the lower MOSFET gate. This pin provides the gate drive for the lower MOSFET.
The OVP pin can be used to drive an external SCR in the event of an overvoltage condition.
This pin provides oscillator switching frequency adjustment. By placing a resistor (R 200kHz switching frequency is increased.
F
» 200kHz +
S
R(k)
Conversely, connecting a pull-up resistor (R VCC reduces the switching frequency.
» 200kHz +
F
S
R(k)
) from this pin to GND, the nominal
T
6
510
´
W
T
410
´
W
T
to GND)
(R
T
) from this pin to
T
7
(R
to 12V)
T
HT82P604B
-
-

Absolute Maximum Ratings

Supply Voltage ......................................... +15V
Input Voltage ............... GND-0.3 to V
CC
+0.3V
Note: These are stress ratings only. Stresses exceeding the range specified under ²Absolute Maxi
mum Ratings² may cause substantial damage to the device. Functional operation of this device at other conditions beyond those listed in the specification is not implied and prolonged expo sure to extreme conditions may affect device reliability.
Storage Temperature ............... -50°Cto125°C
Operating Temperature ............ -20°Cto75°C
3 March 23, 2000
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Electrical Characteristics

Preliminary
HT82P604B
Symbol Parameter
Supply Current
V
CC
I
CC
Nominal Supply 12V Ugate and Lgate Open
Test Conditions
V
CC
Conditions
Power-On Reset
Rising V
Falling V
Rising V
Threshold
CC
Threshold
CC
OCSET
Threshold
12V
12V
12V
V
OCSET
V
OCSET
=4.5V
=4.5V
Oscillator
Free Running Frequency 12V RT=Open 185 200 215 kHz
DV
OSC
Total Variation 12V
Ramp Amplitude 12V RT=Open
6kW<RT to GND<200kW-15 ¾
Reference and DAC
DACOUT Voltage Accuracy 12V
ERROR Amplifier
DC Gain 12V
GBW Gain-Bandwidth Product 12V
SR Slew Rate 12V COMP=10pF
Gate Drivers
V
I
UGATE
R
UGATE
I
LGATE
R
LGATE
Upper Gate Source 12V
Upper Gate Sink 12V
Lower Gate Source 12V
Lower Gate Sink 12V
BOOT-VPHASE
V
I
V
I
UGATE
LGATE
=12V, V
CC
LGATE
=6V
=0.3A
=0.3V
Protection
I
OCSET
I
OVP
I
SS
Over-Voltage Trip (V
/DACOUT)
SEN
OCSET Current Source 12V
OVP Sourcing Current 12V
Soft Start Current 12V
12V
V
OCSET
V
SEN
=4.5V
=5.5, V
Power Good
Upper Threshold (V
/DACOUT)
SEN
12V
V
SEN
Rising
=12V,
LGATE
DC
=0V
OVP
=6V
Min. Typ. Max. Unit
¾
5
¾¾
8.2
¾
¾¾
1.26
10.4 V
¾
¾
mA
V
V
+15 %
1.9
¾
-1.0 ¾
88
¾
15
¾
¾
6
350 500
5.5 10
¾
300 450
3.5 6.5
¾
115 120 %
¾
170 200 230
60
¾¾
10
¾
106
¾
V
¾
+1.0 %
dB
¾
MHz
¾
¾ V/ms
mA
¾
mA
¾
mA
mA
¾mA
111 %
P-P
W
W
4 March 22, 2000
Preliminary
HT82P604B
Symbol Parameter
Lower Threshold (V
/DACOUT)
SEN
Hysteresis (V
/DACOUT)
SEN
V
PGOOD
PGOOD Voltage Low 12V
V
CC
12V
12V

Functional Description

Output voltage program
The output voltage of a HT82P604B converter is programmed to discrete levels between 1.3V and 3.5V. The voltage identification (VID) pins program an internal voltage reference (DACOUT) with a 5-bit digital-to-analog con verter (DAC). The level of DACOUT also sets the PGOOD and OVP thresholds. Table 1 speci fies the DACOUT voltage for the 32 combina tions of open or short connections on the VID pins. The output voltage should not be adjusted while the converter is delivering power. Re move input power before changing the output voltage. Adjusting the output voltage during operation could toggle the PGOOD signal and exercise the overvoltage protection.
Pin Name Nominal
Output
VID4 VID3 VID2 VID1 VID0
01111 1.30
01110 1.35
01101 1.40
01100 1.45
01011 1.50
01010 1.55
01001 1.60
01000 1.65
00111 1.70
00110 1.75
00101 1.80
Voltage Dacout
Test Conditions
Conditions
Falling
V
SEN
Upper and Lower Threshold
=-5mA ¾
I
PGOOD
Min. Typ. Max. Unit
89
¾
¾
2
0.5
Pin Name Nominal
VID4 VID3 VID2 VID1 VID0
-
00100 1.85
00011 1.90
-
-
00010 1.95
00001 2.00
00000 2.05
-
11111 0
11110 2.1
11101 2.2
11100 2.3
11011 2.4
11010 2.5
11001 2.6
11000 2.7
10111 2.8
10110 2.9
10101 3.0
10100 3.1
10011 3.2
10010 3.3
10001 3.4
10000 3.5
Note: 0=connected to GND or VSS, 1=OPEN
Table 1 Output voltage program
94 %
¾
¾
Output Voltage Dacout
%
V
5 March 23, 2000

Application Circuits

4mH
VIN=+5v or +12V
Preliminary
+12V
4x1000mF
HT82P604B
0.1mF
560k
W
VSEN
RT
VID0
VID1
VID2
VID3
VID4
FB
SS
3
1
20
4
5
6
7
8
10
0.01mF
D/A
33pF
1mF
20k
OSC
H T 82P604B
W
0.1mF
10
W
VCC18OVP
M onitor
and
Protection
9 COM P
19
11 GND
0.1mF 22
1k
W
OCSET
2
PGOOD
12
15 B O O T
1413UGATE
PHASE
17
LG A T E
PGND
16
W
1000pF
2.7k
47
W
0
W
W
4mH
V
O
10x1000mF
0.1mF
20k
W
15k
W
0.1mF
6 March 23, 2000
Preliminary
HT82P604B
Holtek Semiconductor Inc. (Headquarters)
No.3 Creation Rd. II, Science-based Industrial Park, Hsinchu, Taiwan, R.O.C. Tel: 886-3-563-1999 Fax: 886-3-563-1189
Holtek Semiconductor Inc. (Taipei Office)
5F, No.576, Sec.7 Chung Hsiao E. Rd., Taipei, Taiwan, R.O.C. Tel: 886-2-2782-9635 Fax: 886-2-2782-9636 Fax: 886-2-2782-7128 (International sales hotline)
Holtek Semiconductor (Hong Kong) Ltd.
RM.711, Tower 2, Cheung Sha Wan Plaza, 833 Cheung Sha Wan Rd., Kowloon, Hong Kong Tel: 852-2-745-8288 Fax: 852-2-742-8657
Copyright ã 2000 by HOLTEK SEMICONDUCTOR INC.
The information appearing in this Data Sheet is believed to be accurate at the time of publication. However, Holtek assumes no responsibility arising from the use of the specifications described. The applications mentioned herein are used solely for the purpose of illustration and Holtek makes no warranty or representation that such applications will be suitable without further modification, nor recommends the use of its products for application that may pres ent a risk to human life due to malfunction or otherwise. Holtek reserves the right to alter its products without prior notification. For the most up-to-date information, please visit our web site at http://www.holtek.com.tw.
7 March 23, 2000
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