Need a -100V Voltage regulator

[sabingautam]

I am designing a power supply that supplies regulated +100V and -100V form a 110V 60 Hz AC source. I got the regulated +100V working but i am stuck with the -100V part. I cannot find a negative voltage regulator to regulate my output from the bridge rectifier. The voltage across my smoothing capacitor is unregulated -184V and i need to bring it down to -100V.


CAN ANYONE HELP ME PLEASE!!!!!
For reference I have attached my circuit

Thank You

[janneman]

Originally Posted by sabingautam

I am designing a power supply that supplies regulated +100V and -100V form a 110V 60 Hz AC source. I got the regulated +100V working but i am stuck with the -100V part. I cannot find a negative voltage regulator to regulate my output from the bridge rectifier. The voltage across my smoothing capacitor is unregulated -184V and i need to bring it down to -100V.


CAN ANYONE HELP ME PLEASE!!!!!
For reference I have attached my circuit

Thank You

If you have another isolated transformer winding you can build another +100V regulator, connect the "+100V" terminal to gnd and use the "gnd" terminal as -100V. Works like a charm.

jan didden

[Elvee]

Here is an example, easily configurable for -100V or any other voltage:
Need Negative High Voltage Regulator Circuit

[Mach5]

Bringing the voltage from 184v down to 100v with a regulator is going to produce a huge amount of heat.
Doing it twice would require a turbine to cool it with.

Can you change the transformer?

[sabingautam]

I don't really want to change the transformer but if there is a better solution for my problem then certainly I would like to hear it.

[okmog]

Originally Posted by sabingautam

I am designing a power supply that supplies regulated +100V and -100V form a 110V 60 Hz AC source. I got the regulated +100V working but i am stuck with the -100V part. I cannot find a negative voltage regulator to regulate my output from the bridge rectifier. The voltage across my smoothing capacitor is unregulated -184V and i need to bring it down to -100V.


CAN ANYONE HELP ME PLEASE!!!!!
For reference I have attached my circuit

Thank You

I would also need a 100v power supply but cant find a suitable voltage regulator for that. Which one have you used. Cant find any info for a "TLC783" ...

[Chris Daly]

Losing 84v in any semiconductor is hard. Consider replacing the transformer so its closer to 100v for each DC polarity.

If the current required on the output isn't too high on the negative rail you could consider a design using a resistive divider or a basic resistor/ zener diode arrangement. For guidance you should use one of the many zener calculators.

If you cannot sacrifice a bit of current, you will need to use a pass transistor and use a resistor/ zener arrangement across its base to get the voltage to negative 110v DC , then reduce the last 10v using a LM337 regulator 1.25x R2/R1 +1 The 337 dislikes anything above 40v differential

But in this example you are asking it to process just 10v. The net result should be good regulation and ripple performance. Use protection diodes by referring to Nat Semi data, as any caps discharging could be traumatic.

You could consider the same for the positive rail, staging down with resistor /zener ( and pass transistor if current is a issue ) to 110v then a LM317 .

Hope this helps / Chris

[sawreyrw]

I can't find anything on the TLC783C? What the hexx is it? I seriously doubt it can handle much current with 84 volts across it. How much outout current do you need?

[woody]

If you could get by with only about 80V then a choke input filter might be worth
looking at. That would get your voltage before the regulator down to between 90
and 100v.

[Chris Daly]

A Choke will regulate current, but not appreciably alter voltage. Define how much current is needed in the circuit then regulate down to 100v with a resistor and zener diodes using calculators widely available for zener regulation. Using a 337 after that will reduce ripple
and as already suggested with protection diodes should be ideal.

So view reduction in two stages simple resistor zener observing polarity for the zener with respective + and - supplies, then regulate the last 10v and reduce reduce ripple with a 337 for negative , and 317 on the + using 1.25x R2/R1 +1 see Nat Semi data for 337 and 317

Schematic to follow

Hope this helps / Chris