Uc3845 Pin Diagram. Pin 3 on the uc3845 is not an overcurrent sense input. Ti s uc3845 is a single ended 500khz current mode pwm controller with 8 4v 7 6v uvlo 50 duty cycle 0c to 70c.
Vc must have a bypass capacitor at least 10 times greater than the gate capacitance of the main switching fet used in the design. The uc3842 and uc3843 oscillator runs at the switching fre quency. Either method causes the output of the pwm comparator to be high refer to block diagram.
Either method causes the output of the pwm comparator to be high refer to block diagram.
Either raise pin 3 above 1v or pull pin 1 below a voltage two diode drops above ground. Parameter symbol conditions min. Total vcc current is the sum of the quiescent vcc current and the. Vcc 7 12 18 i analog controller bias input that provides power to the device.
