ISL6554 Datasheet, PDF (3/16 Pages) Intersil Corporation – Microprocessor CORE Voltage Regulator Using Multi-Phase Buck PWM Control Without Programmable Droop

Simplified Power System Diagram
ISL6554
VSEN
PWM 1
PWM 2
ISL6554
PWM 3
PWM 4
VID
SYNCHRONOUS
RECTIFIED BUCK
CHANNEL
SYNCHRONOUS
RECTIFIED BUCK
CHANNEL
SYNCHRONOUS
RECTIFIED BUCK
CHANNEL
SYNCHRONOUS
RECTIFIED BUCK
CHANNEL
MICROPROCESSOR
Functional Pin Description
VID4 1
VID3 2
VID2 3
VID1 4
VID0 5
COMP 6
FB 7
FS/DIS 8
GND 9
VSEN 10
20 VCC
19 _PGOOD
18 _PWM4
17 _ISEN4
16 _ISEN1
15 _PWM1
14 _PWM2
13 ISEN2
12 ISEN3
11 PWM3
VID4 (Pin 1), VID3 (Pin 2), VID2 (Pin 3), VID1 (Pin 4)
and VID0 (Pin 5)
Voltage Identification inputs from microprocessor. These
pins respond to TTL and 3.3V logic signals. The ISL6554
decodes VID bits to establish the output voltage. See
Table 1.
COMP (Pin 6)
Output of the internal error amplifier. Connect this pin to the
external feedback and compensation network.
FB (Pin 7)
Inverting input of the internal error amplifier.
FS/DIS (Pin 8)
Channel frequency, F_SW, select and disable. A resistor from
this pin to ground sets the switching frequency of the
3
converter. Pulling this pin to ground disables the converter
and three states the PWM outputs. See Figure 10.
GND (Pin 9)
Bias and reference ground. All signals are referenced to this
pin.
VSEN (Pin 10)
Power good monitor input. Connect to the microprocessor-
CORE voltage.
PWM1 (Pin 15), PWM2 (Pin 14), PWM3 (Pin 11) and
PWM4 (Pin 18)
PWM outputs for each driven channel in use. Connect these
pins to the PWM input of an HIP6601/2/3 driver. For systems
which use 3 channels, connect PWM4 high. Two channel
systems connect PWM3 and PWM4 high.
ISEN1 (Pin 16), ISEN2 (Pin 13), ISEN3 (Pin 12) and
ISEN4 (Pin 17)
Current sense inputs from the individual converter channel’s
phase nodes. Unused sense lines MUST be left open.
PGOOD (Pin 19)
Power good. This pin provides a logic-high signal when the
microprocessor CORE voltage is within specified limits and
soft-start has timed out.
VCC (Pin 20)
Bias supply. Connect this pin to a 5V supply.
FN9003.3
February 11, 2005