DESCRIPTION

The UTC UC1100 is a primary control unit for switch mode

charger and adapter applications. The controlled variable is

transferred by an auxiliary winding from the secondary to the

primary side. The device uses Pulse Frequency Modulation (PFM)

method to build discontinuous conduction mode (DCM) flyback

power supplies.

The UTC UC1100 operates in primary-side sensing and

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

eliminates the need of loop compensation circuitry while

maintaining stability. The UTC UC1100 achieves excellent

regulation and high average efficiency, yet meets the requirement

for no-load consumption less than 30mW.

The UTC UC1100 achieves high precision CV/CC regulation

and high power efficiency. It offers comprehensive protection

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

current limiting, output over voltage protection, feedback loop open

protection, short circuit protection, leading edge blanking, VCC

under voltage lockout, etc.

FEATURES

* Primary side control for rectangular constant current and constant voltage output

* 30mW no-load input power feasible

* Tight CC regulation performance

* Sub-microampere start-up current

* Eliminates control loop compensation circuitry

* Eliminates opto-coupler and secondary CV/CC control circuitry

* Random frequency modulation to reduce system EMI

* Flyback topology in DCM operation

* Open feedback protection

* Built-in soft start

* Short circuit protection