TL783 is used like a LM317, same pin out same basic circuit, except that it can handle up to 125v of Vin-Vout delta, making it semi-usable for a regulated high voltage supply, up to maybe 350v.
It is a 3-pin device, input, output, adj. no gnd pin. output floats 1.25v above the adj pin voltage. The main thing to watch out for is to not allow Vin-Vout to exceed the 125v limit. As protection I added a 99v zener string (three 33v 5w zeners in series), across input and output pins, so when Vout is super low (during powering up and charging up the post-reg reservoir) the zener will conduct and keep Vin-Vout within the allowed range. This is the only thing I am doing differently comparing to a standard LM317 circuit.
The data sheet mentioned on/off should be done on the AC side so there is time for the input pin voltage to ramp up instead of "instant on".
During my tests the TL783 drops out of regulation when Vin-Vout is less than 10v. I plan to run it with ~50v delta. For my application (350v output) this allows 50v head room to deal with a 10% main line voltage increase. after that the zener will kick in.
Rx value in the picture are actual measurements (with R1=330 ohms)
Rx should be 51.5k for 200v Vout
It is a 3-pin device, input, output, adj. no gnd pin. output floats 1.25v above the adj pin voltage. The main thing to watch out for is to not allow Vin-Vout to exceed the 125v limit. As protection I added a 99v zener string (three 33v 5w zeners in series), across input and output pins, so when Vout is super low (during powering up and charging up the post-reg reservoir) the zener will conduct and keep Vin-Vout within the allowed range. This is the only thing I am doing differently comparing to a standard LM317 circuit.
The data sheet mentioned on/off should be done on the AC side so there is time for the input pin voltage to ramp up instead of "instant on".
During my tests the TL783 drops out of regulation when Vin-Vout is less than 10v. I plan to run it with ~50v delta. For my application (350v output) this allows 50v head room to deal with a 10% main line voltage increase. after that the zener will kick in.
Rx value in the picture are actual measurements (with R1=330 ohms)
Rx should be 51.5k for 200v Vout
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