Interesting little things...never had to use one before but I came by a bootstrap capacitor high-side FET driver that required one. It is used as a 15V floating charge pump to refresh the boostrap capacitor in order to allow for continuous duty cycles.
It appears that dv/dt can transients mess around with the transformer interwinding capacitance in isolated floating supplies and I couldn't seem to find a 15V floating charge pump IC so I had to go over how a 555 works.
I never knew their comparators were set to 1/3Vcc and 2/3Vcc. Makes the RC time constant directly correlate with the pulses. I always assumed it triggered at Vcc and 0V which I thought was pretty inconvenient since RC time constant only represents 2/3 charge or 1/3 discharge.
Well that's one thing where a PIC can't replace a 555 timer - high voltage applications.
It appears that dv/dt can transients mess around with the transformer interwinding capacitance in isolated floating supplies and I couldn't seem to find a 15V floating charge pump IC so I had to go over how a 555 works.
I never knew their comparators were set to 1/3Vcc and 2/3Vcc. Makes the RC time constant directly correlate with the pulses. I always assumed it triggered at Vcc and 0V which I thought was pretty inconvenient since RC time constant only represents 2/3 charge or 1/3 discharge.
Well that's one thing where a PIC can't replace a 555 timer - high voltage applications.
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