APW1173 Ver la hoja de datos (PDF) - Anpec Electronics

Número de pieza

componentes Descripción

Fabricante

APW1173

2A SWITCH STEP DOWN SWITCHING REGULATOR

Anpec Electronics 

APW1173

Operating waveforms (Cont.)

3. Current Limit :

- VIN = 12V,VOUT = 3.3V

- CIN = 22µF, COUT = 220µF, L = 15 µH

4. Load Transient :

- VIN = 12V,VOUT = 3.3V

- CIN = 22µF, COUT = 220µF, L = 15 µH

IOUT

IOUT

V OUT

COMP

V OUT

Ch1 : VOUT,2V/div

Ch2 : COMP,2V/div

Ch3 : IOUT,2A/div

Time : 2ms/div

Functional Description

Ch1 : VOUT,200mV/div,offset 3.3V

Ch2 : IOUT,1A/div,100mA-3A

Ch2 rising time : 4us

Ch2 falling time : 4us

Time : 10us/div

Power-On-Reset

A Power-On-Reset circuit monitors input voltages at

VCC pin to prevent wrong logic controls. The POR

function initiates immediately by the inductor current

with it’s limit after the supply voltage exceed firstly it’s

threshold voltage after powering on.

Output Voltage Regulation

An error amplifier working with a temperature-compen-

sated 1.235V reference. The error amplifier designed

with high bandwidth and DC gain provides very fast

transient response and less load regulation. It compares

the reference with the feedback voltage and amplifies

the difference in it’s output called error signal. The

error signal feeds into the input terminal of PWM

comparator and compared with internal saw tooth wave.

It generates a PWM control signal by the PWM

comparator. The PWM signal feeds into the logic

circuit and turns on or off the pass element. The Buck

type output stage regulates the correct output voltage

depends on the previous mechanism.

Current Limit

The APW1173 monitors the current flow through the

pass element and limits the maximum output current

to prevent damages during overload or short-circuit

conditions.

Over-Voltage Protection (OVP)

The over voltage protection is realized by using an

Copyright © ANPEC Electronics Corp.

11

Rev. A.5 - Aug., 2005

www.anpec.com.tw

Share Link: