The schematic page doesn't come up here. But, since the LEDs are not an
inductive load, it seems that a high voltage N channel FET between the
bottom of the LED string and ground should do the job. Drive the gate
directly with a PIC. Might put a PTC between the FET and the PIC with
clamp diodes on the PIC side to protect the PIC should the FET fail and
put HV on the gate. I think a FET should be able to sink 150mA with 5V
gate drive, so I don't think a gate driver should be required.

Good luck!

Harold

> PICListers,
>
> I am in urgent need of some help. I need to switch a 160V DC @150mA
> signal (hopefully with PWM around 100Hz)
> using a PIC I/O. The solution I had, which I have used for up to 50V DC
> @ 5A was like a 4th of July
> celebration when hooked up to the 160V DC. It is basically being used
> to power up a "alot" of LEDs
> in series, I can't go into further details. I was thinking of using a
> circuit similar to the one linked below,
> any other recommendations would be greatly appreciated! High voltage
> switching isn't my thing, so any help
> would be wonderful.
>
> http://www.geocities.com/researchtriangle/lab/6584/high_v_switch.bmp
>
> Thanks.
> Steve
>
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>


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