UPSL104A

Preliminary

CMOS IC

UNISONICTECHNOLOGIESCO.,LTD

4 of 6

www.unisonic.com.tw

Ver.a



OPERATION DESCRIPTION

UTC UPSL104A is a primary side regulation off-line LED lighting controller which can achieve accurate LED

current. It significantly simplifies LED lighting system design by eliminating the secondary side feedback circuitry.

The device integrates PWM controller to enhance the performance of discontinuous conduction mode (DCM) flyback

converters.

Startup control

be used to minimize the power loss in application because the start current of UTC UPSL104A is very low. When the

Operating Current

The Operating current of UTC UPSL104A is as low as 1.6mA. Good efficiency and very low standby power can be

achieved.

Constant Current Operation

When the sampled voltage is below 2.0V reference voltage and the error amplifier output reaches its maximum,

thus UTC UPSL104A operates in constant-current (CC) mode. The CC point and maximum output power can be

externally adjusted by external current sense resistor Rcs. The larger Rcs, the smaller CC point is, and the smaller

output power becomes.

Iout

Vout

Large

Rcs

Small

Rcs

Adjustable Output Power By Changing Rcs

Iout

Is

Tdemag

Tsw

t

Ipks

Secondary Current Waveform