AP3771

Document number: DS37281 Rev. 1 - 2

1 of 11

www.diodes.com

May 2014

© Diodes Incorporated

AP3771

A Product Line of

Diodes Incorporated

LOW-POWER OFF-LINE PRIMARY SIDE REGULATION CONTROLLER

Description

The AP3771 is a high performance AC/DC power supply controller for

battery charger and adapter applications. The device uses Pulse

Frequency

Modulation

(PFM)

method

to

build

discontinuous

conduction mode (DCM) flyback power supplies.

The AP3771 provides accurate constant voltage, constant current

(CV/CC) regulation without requiring an opto-coupler and the

secondary control circuitry. It also eliminates the need of loop

compensation circuitry while maintaining good stability. The AP3771

can achieve excellent regulation and high average efficiency, yet

meets no-load consumption less than 30mW. It can also achieve

excellent dynamic performance while maintaining 30mW standby

power with AP4340.

The AP3771 has a built-in fixed cable voltage drop compensation

function. The cable compensation voltage is set as 7% and 3% of the

rated output voltage.

It also has an adjustable built-in line

compensation function to achieve tight CC.

The AP3771 drives MOSFET to achieve the high switching frequency

and high efficiency.

The AP3771 is available in SOT26 package.

Features



Primary Side Control for Tight Constant Current and Constant

Voltage



30mW No-load Input Power



Excellent

Dynamic

Performance

with

AP4340

(For

5V

Application)



MOSFET Driving



Proprietary Adjustable Line Compensation for CC Variation



Constant and Built-in 7% and 3% Voltage Drop Compensation



Enhanced Audio Noise Suppression



Open Circuit Protection



Over Voltage Protection



Short Circuit Protection



SOT26 Package



Totally Lead-free & Fully RoHS Compliant (Notes 1 & 2)



Halogen and Antimony Free.

“Green” Device (Note 3)

Pin Assignments

(Top View)

GATE

GND

VCC

CS

CPC

FB

1

2

3

4

5

Pin 1 Mark

6

SOT26

Applications



Adapters/Chargers for Cell/Cordless Phones, PDAs, MP3 and

Other Portable Devices



LED Driver



Standby and Auxiliary Power Supplies

Notes:

1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.

2. See http://www.diodes.com/quality/lead_free.html

for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green"

and Lead-free.

3. Halogen- and Antimony-

free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and

<1000ppm antimony compounds.