UNISONIC TECHNOLOGIES CO., LTD

US1651

Preliminary

CMOS IC

www.unisonic.com.tw

1 of 7

Copyright © 2015 Unisonic Technologies Co., Ltd

QW-R129-005.a

PRIMARY-SIDE REGULATION

PWM POWER SWITCH

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DESCRIPTION

The UTC US1651 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 US1651 operates in primary-side sensing and

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

operates in fixed frequency mode at large load conditions,

frequency reduction mode at light/medium load and ‘Extended

burst mode’ at No/light load conditions. So that low standby power

can be achieved.

The UTC US1651 achieves high precision CV/CC regulation

and high power efficiency. It offers comprehensive protection

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

SOP-8

* Programmable CV and CC regulation

* Primary-side sensing and regulation with No TL431 and

opto-coupler

* Multi-mode operation for high efficiency

* Adjustable constant current and output power setting

* Power on soft-start time (4ms)

* Frequency shuffling and adjustable gate drive greatly

improving EMI

* ”Extended burst mode control” for improved efficiency

and minimum standby design

* Built-in leading edge blanking (LEB)

* Cycle-by-Cycle current limiting

* Fail-safe protection for open loop fault condition

* Auto-restart in over voltage condition

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ORDERING INFORMATION

Ordering Number

Package

Packing

US1651G-S08-R

SOP-8

Tape Reel