Adding a resistor and zeners to Control pin
Hi,
This PS has passed all EMC tests (emission, immunity, harmonics flicker, transient etc..). It is now undergoing safety requirement test.
R33, D7 and D8 were added after the EMC tests to limit the current and the voltage to U2 as required by the test house. I have tested this circuit and did not have any obvious effect on the performance of the circuit.
Can you see any problem by addidng these three components in?
Thank you.
Comments
Hi PI-Scotty, how can I measure the transient response? The voltage rating of the Zeners are 30V. Vbias is 20V almost ripple free across Vinput of 85 - 265Vac.
I would like to add another question which I think is relevant... We need to drive a capacitive load of up to 470uF with this PS. At the moment the PS is struggling to do that. It sees a short circuit at the output and gone into hiccup mode. Let me know if you think I should raise a new topic for this question.
Thanks.
Hi,
I guess you are ok using R33, D7 and D8.
Regarding your second question, what is the Kp of your transformer design? Can you please send me the power -up waveform of your supply when driving a 470uF capacitive load?
rgds
Hi,
Try adding a resistor (100R) in series with a capacitor(0.1uF) across the TL431 to solve the start-up problem.. Please see attachment.
Hi,
How does the transient reponse looks like with and without R33?What are voltage ratingof the Zeners?
rgds..