Other Parts Discussed in Thread: UC1825, UC1823
Short description: Unable to obtain PWM duty cycle of less than 30% with UC3823A.Case details or comments:
When error amplifier output voltage (pin 3) is lowered, the duty cycle reduces smoothly from 95% to about 30%. When it reaches 30% further reduction of the error amp output voltage causes the IC to skip pulses and then go completely off. When placing a UC1825 in the same socket for comparison, duty cycle can be varied smoothly from 50% to about 7% duty cycle as expected. Frequency is 250kHz and the ramp is a clean sawtooth.