TL783 HV reggy

[richwalters]

Anyone using this regulator in a project ? Although the working performance is quoted good, I've noticed it making peculiar noises and going unstable when input volts drops below regulation range.

I used this reg in a tube amp and found it making noises when power was turned off. Thinking the amp was unstable, it turned out this ic was the culprit.
Anyone got a circuit diagram of this ic , or a viable solution ?

Adding a good layout and more decoupling caps doesn't improve.

richj

[Nisbeth]

Originally posted by richwalters
Although the working performance is quoted good, I've noticed it making peculiar noises and going unstable when input volts drops below regulation range.

I think that's to be expected if you let the regulator drop out of regulation. Can't you try and decrease the output voltage by a few volts to keep it within regulation all the time?


/U.

[richwalters]

Originally posted by Nisbeth

I think that's to be expected if you let the regulator drop out of regulation.

/U.

I personally view this reg is a bad design in the analogue world. I certainly won't use it anymore. If the standard 78 series can work smoothly below drop-out without oscillating then this is a solid reason why they have got industry standard.
On the other hand, no-one likes to build equipment using stuff which is prone to oscillate.

richj