Voltage Drop Alternatives for Analog Power Circuit.

[witssq]

I would like to design Power supply with very stable and low ripple for analog measurement application.

For regulation from +15 to +5V, from -15 to -5V 3A, about 3Vx3A voltage drop is needed for too much heat.

Please advice me a better alternative for voltage drop under stabilty and ripple basis.
Which one would be better among (1)- wirewound resistor and (2) diodes alternative as attached?
Or does any other better alternatives exist?

Awaiting kind response,
Thanks.

 

[keith1200rs]

I do not understand your calculation of 3Vx3A. Are you wanting to drop from 15V to 5V at 3A? That is a 10V drop and so 30W, plus the same for the -15V. That is a lot of power. You would be far better to look at switching regulators and add some good filtering. Have a look at the power supply design tools on manufacturers' web sites such as www.National.com

Keith

 

[witssq]

Hi, Keith

I do not understand your calculation of 3Vx3A. Are you wanting to drop from 15V to 5V at 3A? That is a 10V drop and so 30W, plus the same for the -15V. That is a lot of power. You would be far better to look at switching regulators and add some good filtering. Have a look at the power supply design tools on manufacturers' web sites such as www.National.com

The voltage drop needed is 3Vx3A, the remained voltage drop would be covered
by regulator.

Thanks,

 

[keith1200rs]

The voltage drop needed is 3Vx3A, the remained voltage drop would be covered
by regulator.

Thanks,

Ok. My earlier comments still apply - use a switcher! If you really don't want to rely on filtering you could regulate with a switcher to maybe 0.5V above the desired voltage and use a low dropout linear regulator to drop the rest.

Keith.

 

[witssq]

Hi,

Thanks for your comment.

Not good-experienced, I would like to know what switcher mentioned is.
If possible, please let me know where I find sample schematic.


Best regards,

SunSung Hwang

 

[keith1200rs]

Go to www.national.com At the top right you should see "WEBENCH designer". Type your requirements in then and click "start design". A new window will appear with a choice of chips which will do the job. It also losts cost, size, number of components, efficiency etc. Pick one and it will show you the design and parts list. I have attached an example.

Keith.