Charge pump ripple reduction

[pmr9]

Hi, planning to design charge pump doubler, any ripple reduction techniques recommended would be helpful.
Are there any papers/lit that suggest ripple reduction?

 

[tpetar]

Method to Reduce the Output Ripple & Noise of Power Supplies
http://www.aimtec.com/site/Aimtec/f...016e - reduction of output ripple & noise.pdf

Understanding, Measuring, and Reducing Output Voltage Ripple
http://e2e.ti.com/support/power_man...uring-and-reducing-output-voltage-ripple.aspx



Best regards,
Peter

 

[BradtheRad]

To reduce ripple V at the output, you can use the same approach as for a conventional smoothing capacitor with 50/60 Hz rectified AC.

The aim is to reduce the voltage swing on the capacitors. This means their value should be large enough that their charge level does not change much as current goes through it in either direction.

The RC time constant comes into play here. If you have (a) a load R, and (b) a desired operating frequency, and (c) a max spec for voltage ripple...

Then you can calculate the value for the smoothing capacitor.

As for the charge pump capacitor, it has to be large enough to maintain a charge on the smoothing capacitor. As it turns out, they should have approximately the same value.