Datasheet HT82P604B Datasheet (Holtek Semiconductor Inc)

HT82P604B

Preliminary

Features

Operating voltage: 5V~12V

·

Drives two N-Channel MOSFETs

·

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

·

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±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

-

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

-

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

-

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: [phone]
Fax: [phone]

Holtek Semiconductor Inc. (Taipei Office)

5F, No.576, Sec.7 Chung Hsiao E. Rd., Taipei, Taiwan, R.O.C.
Tel: [phone]
Fax: [phone]
Fax: [phone] (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: [phone]
Fax: [phone]

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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