TIP50 voltage regulator

[jj2]

I would like to install TIP50 to regulate 315v for my 45 amp.
but don't know how to apply TIP50 to the amp.
how can I adjust it to regulate different voltage ?
have upload pic, please check.

Thanks John

[jeapel]

ok 315v for vout but very important you need Iout(max) = ??
10ma or 100 ma or ??

[jj2]

Originally posted by jeapel
ok 315v for vout but very important you need Iout(max) = ??
10ma or 100 ma or ??

Thanks for the reply
need 40ma in the output.

[anatech]

Hi John,
That's going to dissipate around 1.7W (just over), so you will need a heatsink for sure.

Right now you really only show a pass element. You need the rest of the circuit.

So you will have the 358 V in to the collector and take your 315 V from the emitter side. Have a look for some HV regulators (search). Regulators using an error amp will have much better performance than just a zener stack type.

-Chris

[jeapel]

something like that but no guarantee i don t try this design

[jeapel]

i forget i hope your input 358v is with the load connected

[anatech]

Hi jeapel,
The 1N5408 could just as easily be a 1N4007 (cheaper). That circuit will work but I haven't calculated the dissipations. You may need a darlington hookup depending on delta I.

Why the devil do you need 40mA John? That is a lot, like 12 ~ 13 watts. Not enough for an output stage and too much for a preamp.

-Chris

[jj2]

Originally posted by anatech
Hi jeapel,
The 1N5408 could just as easily be a 1N4007 (cheaper). That circuit will work but I haven't calculated the dissipations. You may need a darlington hookup depending on delta I.

Why the devil do you need 40mA John? That is a lot, like 12 ~ 13 watts. Not enough for an output stage and too much for a preamp.

-Chris

Trying to run a 45 on 215V with 32ma.
I still don't get how to use the TIP50 with different voltage.
Thanks John.

[anatech]

Hi John,
That's 315 volts, right?

The transistor (TIP50 in this case) simply amplifies the current going into it's base. There is a voltage drop of 0.6 ~ 0.8 volts in that current range as a guess. Most people just call it a volt.

As long as you can maintain "X" number of volts at the transistor's base at the current required you should be good to go (within the ratings of the transistor). This would be [output current / transistor DC beta]. If you were drawing 40 mA and the beta was 10, you would need to supply 4 mA into the base and some down the zener string.

ALERT! If the load current drops to zero, the zeners now pass the standing current you designed plus the 4 mA. Make sure this will not overheat the zener string. If it will, add another transistor to lower the current variation in the zeners compared to the standing current in the zeners.

The above was just an example. You need to
look at the data sheets.

Clear as mud?

-Chris

[BC]

This circuit may help.

HV Regulator

BC