DAC controlled regulator from 0 to +5 volts at 3,4 or 5 amps

[new2eda]

lm723 dac

Anyone know of a good way to accomplish this.
I have:
LM723's
2N3055's
and most 3 terminal regulators.

But I can't get the design right to give me a dac controlled 0 to +5 volts.

My current circuit uses the LM723 with pot adjustment.

Any help would be greatly appreciated !

Thanks

 

[IanP]

2n3055 voltage regulator

Here is application of 723 voltage regulator and 2N3055 power transistor:
**broken link removed**
Instead of potentiometer and R2 you can feed 0-5V through a voltage divider directly to (+) input of 723 error amplifier.
However, I don't believe that in this circuit you will be able to generate voltages close to 0V ..

Below is different example of 0-something power supply ..
In this example you can remove bottom part of the circuit (current control) and again, instead of P2 feed 0-5V from DAC through a voltage divider (output range) to error amplifier based on 3140 opamp ..

In both cases for 0-5V outpu you will need ≈10-12V unregulated DC voltage at smoothing capacitor at full load (5A) ..
Also, don't forget about huge heatsink for 2N3055 (10V @ 5A = 50W of heat) ..

Regards,
IanP

 

[new2eda]

voltage regulator circuit lm723 0 to 10v

Thanks, I really appreciate it.
I have the LM723 up and running, is there a way to add a negative -1.25V to the circuit you show in link and make it give 0 volts out ?

Thanks for all your help, I sent you points, I think that is what I'm suppose to do.

 

[IanP]

dac simple circuits

You can always generate negative voltage from positive using charge pumps (example SI7661: **broken link removed** ) or you can build a simple circuit based on very popular timer IC 555 (see attached picture) .. add zener diode to stabilize this negative voltage and use it as negative reference for 723 voltage regulator ..
Regards,
IanP

 

[new2eda]

of723 diode

IanP,
Ok, sounds good, but since I have the LM723 running like the one you posted in the link, can't I just use a 1.5V battery connected as negative for a reference just for testing.
Where in this circuit would you connect a negative reference to make the output go to 0 volts?

**broken link removed**

IanP, again, thanks for your help !

 

[IanP]

dac control for a regulator

Try bottom of R2, bottom of R5 and (-)V of 723 ..
This should do ..
Regard,
IanP

 

[new2eda]

voltage regulator with dac

Ian,
Many thanks, I'll give it a try and see if I can DAC control it with 0 to +10 with a resistor divder and supply a negative reference as you indicated.

Thank you !