Copyright

© ANPEC Electronics Corp.

Rev. A.3 - Sep., 2012

APW8811

www.anpec.com.tw

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ANPEC reserves the right to make changes to improve reliability or manufacturability without notice, and

advise customers to obtain the latest version of relevant information to verify before placing orders.

System Power PWM Controller for Notebook Computers

Features

racy Over-Temperature

- PWM1 Controller with Adjustable (2V to 5.5V) Out-

put

- PWM2 Controller with Adjustable (2V to 5.5V) Out-

put

- 100mA Low Dropout Regulator (LDO5) with Fixed

5V Output

- 100mA Low Dropout Regulator (LDO3) with Fixed

3.3V Output

Temperature Range

(with Selectable Ultrasonic Operation)

Compensation for PWM Mode

Stop for PWM Outputs and LDO Outputs

(PWMs)

tions (PWM)

- Using Sense Low-Side MOSFET’s R

DS(ON)

Compliant)

General Description

Simplified Application Circuit

The APW8811 integrates dual step-down, constant-on-

time, synchronous PWM controllers (that drives dual N-

channel MOSFETs for each channel) and two low drop-

out regulators as well as various protections into a chip.

The PWM controllers step down high voltage of a battery

to generate low-voltage for NB applications. The output of

PWM1 and PWM2 can be adjusted from 2V to 5.5V by

setting a resistive voltage-divider from VOUTx to GND.

The linear regulators provide 5V and 3.3V output for

standby power supply. The linear regulators provide up

to 100mA output current. When the PWMx output voltage

is higher than LDOx bypass threshold, the related LDOx

regulator is shut off and its output is connected to VOUTx

by internal switchover MOSFET. It can save power

dissipation.

The APW8811 provides excellent transient response and

accurate DC output voltage in either PFM or PWM Mode.

In Pulse-Frequency Mode (PFM), the APW8811 provides

very high efficiency over light to heavy loads with loading-

modulated switching frequencies. The Forced-PWM

mode works nearly at constant frequency for low-noise

requirements. The unique ultrasonic mode maintains the

switching frequency above 25KHz, which eliminates

noise in audio applications.

The APW8811 is equipped with accurate sourcing cur-

rent-limit, output under-voltage and output over-voltage

protections, being perfect for NB applications. A 1.7ms

V

OUT2

L2

Q3

PWM2

Q4

V

OUT1

V

IN

6V~28V

PWM1

L1

Q1

Q2

LDO5

LDO3

V

LDO3

V

LDO5

EN LDO

EN PWM

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