APW7108
Operating Waveforms (Cont.)
Operating at Heavy Load of 5A (CH1)
1
2
3
4
CH1: VOUT1 (AC, 100mV/div)
CH2: VPHASE1 (20V/div)
CH3: IL1 (2A/div)
CH4: VOUT2 (AC, 100mV/div)
Time: 2ms/div
Pin Description
PIN
NAME
FUNCTION
QFN-24
SSOP-28
22
1
GND
Signal ground for the IC.
Output of the low-side MOSFET driver (PWM 1). Connect this pin to Gate of the low-side
MOSFET. Swings from PGND1 or PGND to VCC.
23
-
2
3
LGATE1
Power ground of the LGATE1 low-side MOSFET driver. Connect the pin to the Source of
the low-side MOSFET.
PGND1
PHASE1
UGATE1
BOOT1
Junction point of the high-side MOSFET Source, output filter inductor and the low-side
MOSFET Drain. Connect this pin to the Source of the high-side MOSFET. PHASE1
serves as the lower supply rail for the UGATE1 high-side gate driver.
24
1
4
5
6
Output of the high-side MOSFET driver (PWM 1). Connect this pin to Gate of the
high-side MOSFET.
Supply Input for the UGATE1 Gate Driver and an internal level-shift circuit. Connect to
an external capacitor and diode to create a boosted voltage suitable to drive a logic-level
N-channel MOSFET.
2
Current sense pin (PWM 1). This pin is used to monitor the voltage drop across the
Drain and Source of the low-side MOSFET for current limit. For precise current
detection, this input can be connected to the optional current sense resistor placed in
series with the Source of the low-side MOSFET.
3
7
ISEN1
Enable pin of the PWM 1 controller. The PWM 1 is enabled when EN1=1. When both
EN1 and EN2 are low, the chip is disabled and only low leakage current is taken from
VCC and VIN.
4
5
6
8
9
EN1
Selection pin for PWM 1 controller to operate in either forced PWM or automatic
PFM/PWM mode.
VOUT1
VSEN1
Output voltage feedback pin (PWM1). This pin is connected to the resistive divider that
set the desired output voltage for PWM 1. The PGOOD, UVP, and OVP circuits detect
this signal to report output voltage status.
10
Copyright ã ANPEC Electronics Corp.
12
www.anpec.com.tw
Rev. A.4 - Jan., 2009
ANPEC [ ANPEC ELECTRONICS COROPRATION ]
