multiple output power supply (tny266) output ripple
hi,
I build a multiple output power supply (+7.5v, 500mA & -7.5v, 500mA) with tny266 by the help of PI Expert software...
. I used post filter for the output, I need +5v and -5v so Iam using 7805 and 7905 (for compensating cross regulation); but in the output Iam getting 100mV ripple...
How much I can eliminate the ripple if I use very low esr capacitor???
If I use smd components the ripple value will reduce ??
post filter is designed above 8 KHz for frequency jittering....should this frequency affect the output??
frequency below 8 Khz will affect the output??
If I use aluminium polymer and/or low esr ceramic capacitor how much I can reduce the ripple??
thanks and regards,
Anoop
(Thanks for the PI Expert software)
Comments
Iam using output capacitance 1000uf...I used 7805 and 7905 at the outputs of the circuit.... Here I uploaded circuit diagram and output ripple waveform...
please check it and help me to eliminate the problem......
thanks and regards,
Anoop.
| Attachment | Size |
|---|---|
| circuit diagram (70.07 KB) | 70.07 KB |
| ripple waveform 5ms time periode (21 KB) | 21 KB |
| ripple waveform 500uS time periode (21.05 KB) | 21.05 KB |
| ripple waveform 50nS time periode (26.16 KB) | 26.16 KB |
How are you measuring the Ripple? Could you please follow the below ripple measurement procedure and let us know if you are seeing the same issue. Please go through the Page No:38 in the below report.
http://ac-dc.power.com/sites/default/files/PDFFiles/rdr462.pdf
Regards,
PI-KSAN
Hi PI-KSAN,
Thanks for your reply....I followed the doccument you share...I used two series 100uf, 25v electrolytic capacitors (50uf) and 0.1uf ceramic capacitor in parallel. Now the ripple wave is reduced upto 28mV (my circuit is not connected to load)....Here below I uploaded the testing probe photo and the ripple waveforms....Please give me further guidance...
Thanks and regards,
Anoop.
| Attachment | Size |
|---|---|
| probe photo (1.96 MB) | 1.96 MB |
| +ve side ripple at 10us time periode (27.75 KB) | 27.75 KB |
| +ve side ripple at 5ns time periode (41.35 KB) | 41.35 KB |
| -ve side ripple at 20us time periode (27.71 KB) | 27.71 KB |
| -ve side ripple at 20ns time periode (26.57 KB) | 26.57 KB |
Hi Anoop,
The ripple measurements that you sent us are measured at No Load? At what line input , also measure with Load? How much peak to peak ripple is your specification? Could you please let us know what exactly are you looking for?
Regards,
PI-KSAN
Hi PI-KSAN,
Thanks for your reply...I connected the load and tested the ripple output at 230V input...positve side I got 11mV ripple and negative side I am getting 19mV. I have to reduce the negative side ripple to same level as in positive side..
regards,
Anoop.
| Attachment | Size |
|---|---|
| positive side (26.99 KB) | 26.99 KB |
| negative side (39.3 KB) | 39.3 KB |
Hi anoop,
Could you please explain what does negative side and Postive side mean? ripple should be measured across the output voltage terminal with respect to gnd with short probe method.
Regards,
PI-KSAN
Hi,
Thanks for your reply...Now the ripple voltage is as per my requirements(its ok now)..
Regards,
Anoop.
Hii....
I have designed SMPS with universal input (85-265V) and Fixed output 24V/3Amp using PI Expert.By testing the SMPS work correctly but there is high ripple during switching.
when we test SMPS without load then 2V (P-P) ripple generated at output. and when we add load then heavy ripple generated.
Please help us to reduce the ripple in SMPS.
Hello RUTUJA SANJAY B...
We are willing to help you in your inquiry but please kindly create a separate ticket on this. If you think that this thread is related to your inquiry then you may copy the link in your new post instead. We'll wait for your new post.
Best Regards,
PI-Lupin
Hii sir...
I have no any idea to create new post.please help me to create a separate post.
Hi RUTU,
I think you were already able to create one.
https://ac-dc.power.com/forum/high-power-design/2021/about-top-switch-based-smps-ripple-problem/
Thanks and regards,
PI-Lupin
Thanks for Posting your question into forum. What's the value of your output Capacitance? Could you please send us the Output Voltage ripple waveform? Increase the Output Capacitance , it will reduce the ripple. Also please send us the schematic.
Regards,
PI-KSAN