mbeck@ai.mit.edu (Mark Becker) (12/04/90)
Hello * I'm trying to work up a design for a PWM switching regulator using a TL-594 IC. +12 to -13.6, 750 mA, f(osc) about 110 KHz. So far I've got it generating -13.6 from +12 at about 30 milliamps That works fine. Attaching a 20 ohm resistor for a test load causes the converter to draw enough current to shut down my bench supply (about 3 amps!). I've measured the current through the flyback inductor (.1 ohm series resistor to measure the voltage drop) and there is no sign of saturation; the curve is nicely linear while the +12V is switched ON. I would appreciate hearing from people with suggestions regarding PWM regulator design. I'm trying to replace a constant-ON-time regulator (TL-497) with a TL-594 PWM to get the sound generated by the inductor out of the range of human hearing. Mark mbeck@ai.mit.edu -or- mbmm!mbeck@talcott.harvard.edu