Other Parts Discussed in Thread: PMP30252
Hi,
Base on demo board(PMP30252) to adjust parameters make the output to 24V / 0.5A
base on Fixed parameters, the output ripple voltage at no load about 700mV,
so I adjust to feedback parameters, the ripple is reduce, but noise still high.
the waveform as below:
What is the suggestion that the noise can be eliminated?
Is there a good way to adjust the feedback parameters?
Is it feasible if the output capacitor does not use an electrolytic capacitor?
| Fixed parameters | |||
| Vin= | 9-36 | V | |
| Vo= | 24 | V | |
| Io= | 0.5 | A | |
| T1 Parameter: | pri= | 26 | T |
| sec= | 17 | T | |
| L= | 10 | uH | |
| SW= | 250 | kHz | |
| Correction parameter | |||
| R26= | 2.23 | kohm | |
| R11= | 150 | kohm | |
| base on Fixed parameters, the output ripple voltage at no load test waveform as below: | In the same test condition, adjust feedback parameters: C18=22nF, C19=220nF, R24=10kohm, test waveform as below: |
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| Vin=10V, Vo=24V, Io=0A | Vin=10V, Vo=24V, Io=0A | ||||||||||||||||||||||||||||||||
| ripplw voltage= 700mV | the ripple is reduce, but noise still high. | ||||||||||||||||||||||||||||||||
| we can find the noise is coupling of primary side switching frequency. | |||||||||||||||||||||||||||||||||
thanks.
