UC3863

DESCRIPTION

The UC3863 is a high performance current mode PWM

controller ideally suited for low standby power. The PWM switching

frequency is programmable externally at normal operation. Low

V DD startup current make the power reliable on startup design and

a large value resistor could be used in the startup circuit to

minimize the standby power. At no load condition, the IC operates

in power-saving mode for lower standby power, decreasing

frequency for Higher conversion efficiency at light load condition.

The UC3863 contains protection with automatic recovery

including OLP (over load protection), OTP (over temperature

protection), OVP (over voltage protection), UVLO (V DD over voltage clamp and under voltage lockout).To protect

the power MOSFET, Gate-drive output is fixed up to 15V max. The UC3863 contains protection OCP (cycle-by-cycle

current limiting).

The internal slope compensation improves system stability at high PWM duty cycle output. Leading-edge

blanking on current sense input removes the signal glitch, which offering minimal external component count in the

design. Excellent EMI performance is achieved with UTC proprietary frequency hopping technique

(ZL201020615247.1) together with soft driver control. Audio noise is eliminated due to switch frequency more than

20kHz during operation.

The UC3863 has such applications as: battery charger, power adaptor, set-top box power supplies, ink jet

printers, open-frame SMPS.

FEATURES

* UTC proprietary frequency hopping technology for Improved EMI

  performance.

* Power-saving mode for high light-load and standby efficiency

* Dynamic peak current limiting for constant output power

* Built-in synchronized slope compensation

* OTP,OLP,OVP and V DD clamp for higher security

* Programmable PWM Frequency

* Gate output voltage clamped at 15V

* Low start-up current

* Cycle-by-cycle Current Limiting

* Under voltage lockout (UVLO)

* Few external components required

规格书UC3863