ISL6232 Datasheet, PDF (10/25 Pages) Intersil Corporation – High Efficiency System Power Supply Controller for Notebook Computers

ISL6232
Typical Operating Performance Circuit in Figure 29, no load on LDO5, LDO3, OUT3 OUT5, and REF, VIN = 12V,
EN3 = EN5 = VCC, SHDN# = VIN, T_A = 25°C, unless otherwise noted. (Continued)
V_OUT5
(100mV/DIV)
IL3
(2A/DIV)
IL5
(5A/DIV)
V_OUT3
(2V/DIV)
V_OUT5
(5V/DIV)
FIGURE 25. SOFT-START WAVEFORMS
IL3
(2A/DIV)
L_GATE3
(5V/DIV)
FIGURE 26. 5V PWM-MODE LOAD TRANSIENT RESPONSE
V_OUT3
(100mV/DIV)
IL3
(2A/DIV)
L_GATE3
(5V/DIV)
FIGURE 27. 3.3V PWM-MODE LOAD TRANSIENT RESPONSE
Functional Pin Descriptions
BOOT3
It powers the upper MOSFET driver for OUT3. Connect a
0.1µF ceramic capacitor to PHASE3.
BOOT5
It powers the upper MOSFET driver for OUT5. Connect a
0.1µF ceramic capacitor to PHASE5.
UGATE3
High side N-MOSFET gate drive output for OUT3. Swing
between PHASE3 and BOOT3.
UGATE5
High side N-MOSFET gate drive output for OUT5. Swing
between PHASE5 and BOOT5.
LGATE3, LGATE5
Low-side N-MOSFET gate drive outputs for OUT3 and
OUT5, respectively. Swing between 0V and LDO5.
LDO3
3.3V internal LDO output. It can provide a total of 100mA. If
OUT3 is greater than the LDO3 switch-over threshold, the
LDO3 regulator shuts down and LDO3 pin connects to OUT3
through a 2.5Ω switch. Bypass a 4.7µF ceramic capacitor to
ground.
FB3, FB5
Output feedback inputs for OUT3 and OUT5. Connect to
ground for fixed 3.3V and 5V outputs. Connect to output
through a voltage divider for adjustable outputs.
CS3, CS5
Inductor current sensing positive inputs for OUT3 and OUT5.
The current sensing signal is compared with the 80mV
internal set threshold to perform overcurrent protection. It
has negative 20mV current limit for ultrasonic skipping mode
operation. It is also used as current ramp for current mode
control.
10
FN9116.1
April 20, 2009