UNISONIC TECHNOLOGIES CO., LTD

USR3651

Preliminary

CMOS IC

www.unisonic.com.tw

1 of 8

Copyright © 2018 Unisonic Technologies Co., Ltd

HIGH PRECISION CC/CV

PRIMARY-SIDE PWM POWER

SWITCH



DESCRIPTION

The UTC USR3651 is a primary control switch mode charger

and adapter applications. The controlled variable is transferred by

an auxiliary winding from the secondary to the primary side. The

device integrates PWM controller to enhance the performance of

discontinuous conduction mode (DCM) flyback converters.

The UTC USR3651 operates in primary-side sensing and

regulation. Opto-coupler and TL431 could be eliminated. It also

provides off-time modulation to linearly decrease PWM frequency

under light-load conditions so that low standby power can be

achieved.

The UTC USR3651 achieves high precision CV/CC regulation

and high power efficiency. It offers comprehensive protection

coverage with auto-recovery features including Cycle-by-cycle



FEATURES

* Built-in 650V Power MOSFET

* ±5% constant voltage regulation at universal AC input

* High precision constant current regulation at universal AC input

* Primary side control without TL431 and opto-coupler

* Programmable CV and CC regulation

* Programmable cable compensation in CV mode

* Flyback topology in DCM operation

* Frequency hopping to reduce system EMI

* Built-in leading edge blanking

* Built-in primary winding inductance

compensation

* Power on soft start

* Gate Output Maximum Voltage Clamped at

15V

* Cycle-by-cycle current limiting

* Over voltage protection

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ORDERING INFORMATION

Ordering Number

Lead Free

Halogen Free

Package

Packing

USR3651L-S08-R

USR3651G-S08-R

SOP-8

Tape Reel