Hi chaps,
I made a previous post about driving a flashing led from
240v ac with a 'or' from two sources, turned out ok...Here's a different problem I've been toying around with and I dont like the feel of what I've done so far, so looking to do a little brainstorming, here it is...
Have a single source of power that goes from 9v steady DC to 500v pulsed (not AC), in that in the first few seconds its a fairly steady 9v +20%, then starts pulsing at 500v with a duty cycle of 5% but returns to
30v for 20% of the time and 12v for the remaining 75% of the period. Period is approx 30ms overall but can reduce to 10ms, complication is the 500v pulse is same period, so the duty cycle for that relatively goes up as overal period goes down.With this single source of power I need to draw off about 0.5W and drive a 'module' at 9 to 11v with some cmos logic along with a few leds etc.
My problemo is keep the cost down , no relays unfortunately but drive this module without having it blow up or be unreliable because its only power source line goes from 9v steady to
500v pulsed.The circuit I have so far is a high voltage transistor configured as a constant current drive into a resistor and 12v zener to spread the dissipation and filter with a 100uF electro 25VW. This seems to be ok but uses a few components and there isnt much gain at the low volts of the constant current source to charge up the electro quickly enough before the 500v pulses start coming...
So I'm opening this to the public forum to see if any lateral ideas come up cause I have exhausted mine (so far, afaik) :(