AIC1533 Просмотр технического описания (PDF) - Analog Intergrations

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Компоненты Описание

производитель

AIC1533

Triple-Output LCD Power Supply

Analog Intergrations 

AIC1533

PIN DESCRIPTIONS

PIN 1: ADJ

PIN 2: OUT

PIN 3: FBP

- Providing VADJ=1.25V (typ.) for

adjustable VOUT.

- Adjustable LDO regulator

output.

- Positive charge pump feedback

input. Regulates to 1.25V

typical.

PIN 4: SHDN

- Active-Low logic level shutdown

input. Connecting SHDN to VCC

for typical operation.

PIN 5: VCC - Supply input.

PIN 6: SUPP - Positive charge pump supply pin.

It monitors negative charge

pump.

PIN 7: SWP

- Positive charge pump driver

output. Output high level is VCC,

and low level is GND.

PIN 8: PGND - Power ground. Connecting to

GND.

PIN 9: SWN

- Negative charge pump driver

output. Output high level is VCC,

and low level is GND.

PIN 10: TN - Programmable delay time pin.

The capacitor on this pin sets

negative charge pump to

provide independent time control.

Or TN connects to high level

directly if it is not in use for

programming delay time.

PIN 11: TP

- Programmable delay time pin.

The capacitor on this pin sets

positive charge pump to provide

independent time control. Or TP

connects to high level directly if

it is not in use for programming

delay time.

PIN 12: FBN - Negative charge pump feedback

input. Regulates to 0V typical.

PIN 13: VREF - Internal reference bypass

terminal. Connecting a 0.22µF

capacitor to ground. Providing a

positive voltage greater than

negative feedback voltage to

obtain a positive voltage for

FBN.

PIN 14: GND - Ground. Tie GND pin directly to

local ground plane to obtain best

performance.

APPLICATION INFORMATION

Introduction

AIC1533 is composed of dual charge pumps and a

regulator to provide three independent regulated

voltages exclusively designed for thin-film transistor

(TFT) liquid crystal display (LCD) applications. LDO

regulator has an adjustable output voltage with a

low dropout voltage of 500mV at 300mA load

current. Two independent charge pumps regulate a

positive output and a negative output by using a

1MHz switching frequency, and a

pulse-width-modulation (PWM) architecture.

AIC1533 provides a start-up sequence function with

an adjustable start-up delay time. In shutdown

mode, it only consumes 0.1µA supply current.

AIC1533 also features an internal current limit and

thermal shutdown protection.

Operation

As Fig. 16 shows, two internal MOSFETs - Q2, Q3,

and external components comprise a positive

charge pump, whose output is three times as much

as input voltage. After delay time, which determined

by CP, Q1 turns on. During on state, which indicates

Q2 is at off stage and Q3 at on stage, CFLY1

connects VCC and PGND and is charged by VCC.

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