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
-
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
1March 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 NameI/ODescription
1VSENI
2OCSETI
3SSO
4~8VID0~4I
9, 10COMP, FBI
11GNDP
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
OCSOCSET
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)
-
-
-
2March 23, 2000
Preliminary
Pin No.Pin NameI/ODescription
PGOOD is an open collector output used to indicate the status of
the converter output voltage. This pin is pulled low when the
12PGOODO
13PHASEO
14UGATEO
15BOOTI
16PGNDP
17LGATEO
18VCCPProvide a 12V bias supply for the chip to this pin.
19OVPO
20RTI
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
3March 23, 2000
-
-
Electrical Characteristics
Preliminary
HT82P604B
SymbolParameter
Supply Current
V
CC
I
CC
Nominal Supply12V 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 Frequency12V RT=Open185200215kHz
DV
OSC
Total Variation12V
Ramp Amplitude12V RT=Open
6kW<RT to GND<200kW-15¾
Reference and DAC
DACOUT Voltage Accuracy 12V
ERROR Amplifier
DC Gain12V
GBWGain-Bandwidth Product12V
SRSlew Rate12V COMP=10pF
Gate Drivers
V
I
UGATE
R
UGATE
I
LGATE
R
LGATE
Upper Gate Source12V
Upper Gate Sink12V
Lower Gate Source12V
Lower Gate Sink12V
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 Source12V
OVP Sourcing Current12V
Soft Start Current12V
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
10.4V
¾
¾
mA
V
V
+15%
1.9
¾
-1.0¾
88
¾
15
¾
¾
6
350500
5.510
¾
300450
3.56.5
¾
115120%
¾
170200230
60
¾¾
10
¾
106
¾
V
¾
+1.0%
dB
¾
MHz
¾
¾V/ms
mA
¾
mA
¾
mA
mA
¾mA
111%
P-P
W
W
4March 22, 2000
Preliminary
HT82P604B
SymbolParameter
Lower Threshold
(V
/DACOUT)
SEN
Hysteresis
(V
/DACOUT)
SEN
V
PGOOD
PGOOD Voltage Low12V
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 NameNominal
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
=-5mA¾
I
PGOOD
Min. Typ. Max. Unit
89
¾
¾
2
0.5
Pin NameNominal
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
5March 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
0.1mF22
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
6March 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.
7March 23, 2000
-
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