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[SOLVED] Need Help for Transforming Unregulated DC Supply into Regulated Supply

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hshah8970

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Hello everyone.

I have an unregulated DC supply which I am using to operate a PWM motor driving circuit. When the load is connected, the supply voltage drops.

I need a regulator circuit that will let me regulate the voltage supply. The regulated voltage I require is 12 V and the maximum current I need to be allowed is 5 A.

Any help will be greatly appreciated.

Humza.

P.S. I don't know if this will help, but here's some extra information: The maximum voltage level provided by the unregulated DC supply is 18 V.
 

You don't need voltage regulation and PWM control at the same time. Instead correct the PWM duty cycle according to the actual ouput voltage of the DC supply.
 

@FvM:

Thanks for the response. The DC supply is being used not only to generate the PWM waveform but also to power up opamps in the circuit. I need a constant 12 V supply to keep those opamps powered up thus I need to regulate the unregulated DC supply. Can it be done?
 

Consider regulating only the supply to the op amps. The motor may not need regulated power.

There are voltage regulator IC's such as the 7805.

It won't handle as high as 5A, if you want it to drop 18V to 12V.
Hence the suggestion to use it to supply low-power devices.

When the load is connected, the supply voltage drops.
Click to expand...

This normally happens if your supply comes from rectified AC.

However if adding the load causes the supply to drop below 12V, then it is underpowered and no regulation will cure it.
 
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