Re: High voltage regulator circuit.
I've encountered an issue, the MJE CCS is getting a bit hot, I think at 10mA Vce290v it's right on the max of the SOA. In which case I've looked for beefier PNP transistors, both mosfet and BJT, there are TO247 devices like the MJL4302A - see attached datasheet for the MJE350 and MJL4302A. if you look at both they look to me to be exactly the same as far as SOA max, the only difference being the latter is a TO264 package so able to dissipate more heat.
I've thought about other ways to get a 300v ish 10mA CCS, not sure how practical some of these are.
1) paralleled CCS's ? See attached. With matched MJE350's is this do-able?
2) Quasi complementary CCS, EG PNP tranny like a MJE350 driving a NPN tranny, think this is a daft idea.
3) Use a valve like a 12BH7
4 Use a MJE350 with biggish HS and little fan.
5)MPSA92/MJE350 darlington CCS
Ideas comments welcome TFL, Andy.
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