Copyright

© ANPEC Electronics Corp.

Rev. A.3 - Nov., 2009

APW7120A

www.anpec.com.tw

10

Pin Description

PIN

NO.

NAME

FUNCTION

1

BOOT

This pin provides ground referenced bias voltage to the high-side MOSFET driver. A bootstrap circuit with

a diode connected to 5~12V is used to create a voltage suitable to drive a logic-level N-channel MOSFET.

2

UGATE

Connect this pin to the high-side N-channel MOSFET gate. This pin provides gate drive for the high-side

MOSFET.

3

GND

The GND terminal provides return path for the IC bias current and the low-side MOSFET driver pull-low

current. Connect the pin to the system ground via very low impedance layout on PCBs.

4

LGATE

Connect this pin to the low-side N-channel MOSFET gate. This pin provides gate drive for the low-side

MOSFET.

5

VCC

Connect this pin to a 5~12V supply voltage. This pin provides bias supply for the control circuitry and the

low-side MOSFET driver. The voltage at this pin is monitored for the Power-On-Reset (POR) purpose.

6

FB

converter via an external resistor divider for closed-loop operation. The output voltage set by the resistor

divider is determined using the following formula:

(V)

)

R2

R1

1

(

0.8V

+

⋅

=

The FB pin is also monitored for under and over-voltage events.

7

OCSET

The OCSET is a dual-function input pin for over-current protection and shutdown control. Connect a

µA current

according to the following formula:

(A)

R

0.4V

-

R

A

40

I

DSON

OCSET

PEAK

⋅

=

µ

Pulling and holding this pin below 0.15V with an open drain device, with very low parasitic capacitor, shuts

down the IC with floating output and also resets the over-current counter. Releasing OCSET pin initiates a

new soft-start and the converter works again.

8

PHASE

The pin provides return path for the high-side MOSFET driver pull-low current. Connect this pin to the

high-side MOSFET source.