ISL6232 Datasheet, PDF (13/25 Pages) Intersil Corporation – High Efficiency System Power Supply Controller for Notebook Computers

ISL6232
VIN: 5.5V TO 22V
C13
0.1µF
OUT3
3.3V/5A
C10
10µF
Q3
IRF7807V
RL2d:c42.71µ8HmRWDLC22::142.7mÿΩH
C11
220µF
12mΩ
4.0V
C15: 0.47µF R9: 1.0kΩ
Q4
IRF7811AV
R4: 2.0kΩ
VIN VCC LDO5
ISL6232
BOOT3
BOOT5
C9
0.1µF
UGATE3
PHASE3
UGATE5
PHASE5
LGATE3
LGATE5
CS3
OUT3
GND
C3 R3
270pF 300kΩ
FB3
COMP3
SKIP#
PGND
CS5
OUT5
FB5
COMP5
REF
PGOOD
C14
1µF
C4
0.1µF
5V ALWAYS ON
C1
10µF
Q1
IRF7807V
C6
4.7µF
LL11::66..88µÿHH RDdCc11::212mWΩ
R7:1.5kΩ C8: 0.47µF
Q2
IRF7811AV
R8: 3kΩ
R5
C5
390kΩ 270pF
C7
0.22µF
VCC
R6
100kΩ
OUT5
5V/5A
C2
180µF
12mΩ
6.3V
REF
ON
OFF
EN3
SHDN#
EN5
LDO3
VCC
3.3V ALWAYS ON
C12
4.7µF
FIGURE 29. ISL6232 TYPICAL APPLICATION CIRCUIT WITH DCR CURRENT SENSING
Theory of Operation
The ISL6232 is a high-efficiency quad output controller
optimized for converting battery, wall adapter, or network DC
input voltage into system supply voltages required for
portable applications where high efficiency and low
quiescent supply current are required. The ISL6232
includes two PWM controllers that are fixed at 5V and 3.3V
respectively, or they can be programmed from 0.8V to 5.5V.
Figure 30 shows its functional block diagram. ISL6232 uses
a constant-frequency, 300kHz, peak current-mode PWM
control scheme with 180^o out-of-phase operation for
reducing the input ripple current and also ESR requirement
of the input capacitors. Light-load efficiency is improved by
the variable-frequency pulse-skipping operation that reduces
switching losses and gate-charge losses. In order to
eliminate the audio noise at extremely light load condition,
the ultrasonic pulse skipping mode is selectable by tying
SKIP# pin to REF so that a minimum 25kHz switching
frequency can be maintained.
Each switching-mode step-down circuit includes two
external N-MOSFETs and an LC output filter. The output
voltage is the average AC voltage at PHASE node, which is
regulated by changing the duty cycle of the external
N-MOSFETs. The gate-drive signal to the high side
MOSFET must exceed VIN voltage and is provided by a
0.1µF boost capacitor, which is connected between BOOT
and PHASE.
13
FN9116.1
April 20, 2009