LOW COST POWER-SAVING MODE PWM CONTROLLER FOR FLYBACK CONVERTERS
DESCRIPTION
The UTC UC3876D 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
VDD 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 UTC UC3876D contains protection with automatic recovery
including OLP (over load protection), OTP (over temperature protection), OVP (over voltage protection), UVLO (VDD
over voltage clamp and under voltage lockout).To protect the
power MOSFET, Gate-drive output is fixed up to 16V max. The UTC UC3876D 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 UTC UC3876Dhas such applications as: battery charger, power adaptor, set-top box power supplies, ink jet
printers, open-frame SMPS |
