APW7120A 查看數據表（PDF） - Anpec Electronics

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APW7120A

5V to 12V Supply Voltage, 8-PIN, Synchronous Buck PWM Controller

Anpec Electronics 

APW7120A

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.

This pin is the inverting input of the internal Gm amplifier. Connect this pin to the output (VOUT) of the

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

divider is determined using the following formula:

6

FB

VOUT = 0.8V ⋅ ( 1+ R1 )

(V)

R2

where R1 is the resistor connected from VOUT to FB , and R2 is the resistor connected from FB to GND.

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

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

resistor (ROCSET) from this pin to the Drain of the low-side MOSFET. This resistor, an internal 40µA current

source (IOCSET), and the MOSFET on-resistance (RDSON) set the converter over-current trip level (IPEAK)

according to the following formula:

7

OCSET IPEAK = 40µA ⋅ ROCSET - 0.4V

(A)

RDSON

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.

Copyright © ANPEC Electronics Corp.

10

Rev. A.3 - Nov., 2009

www.anpec.com.tw

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