Thanks for your replay .tell me how to reduce the ringing .and what are the causes for getting the ringing. and one more thing is output voltage is not stable for 2amps load .and up to 1amps output is stable. for 2amps load topswitch ic is getting hot and output voltage goes to drop.Hi,
The waveform may be OK. It is the typical ringing when the current in the inductor becomes zero and thus the diode releases.
Did you read through other threads with SMPS problems?
Then you will already know the most likely errors:
* bad PCP layout --> stricktly follow the datasheet recommendations. Often there are reference designs.
* wrong part selection. Mainly the inductor. --> keep on the datasheet informations.
Added: I've just realized that you build the circuit using a stripboard.
--> With a stripboard it is impossible to comply with the PCB layout recommendations of the datasheet.
--> create a good PCB layout
Klaus
ok thank you.. i will do in PCB.(Sorry for the confused post order)
Hi,
The waveform may be OK. It is the typical ringing when the current in the inductor becomes zero and thus the diode releases.
Did you read through other threads with SMPS problems?
Then you will already know the most likely errors:
* bad PCP layout --> stricktly follow the datasheet recommendations. Often there are reference designs.
* wrong part selection. Mainly the inductor. --> keep on the datasheet informations.
Added: I've just realized that you build the circuit using a stripboard.
--> With a stripboard it is impossible to comply with the PCB layout recommendations of the datasheet.
--> create a good PCB layout
Klaus
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Hi,
The ringing is no problem. --> No need to reduce it.
The problem most likely is your PCB layout. It is not suitable for power switching circuits.
--> Create a suitable PCB layout and you are done.
It makes no sense to discuss about your stripboard design. It's a waste of time.
(For sure there may be working flyback circuits build on a stripboard ... but it is not reliable...it's more out of luck if they work)
Klaus
here is how to layout an smps on a pcb
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basically, dont run high di/dt power switching currents through lengths of control gnd, and keep power switching current loops in as narrow area loops as possible.
Hi,
I wonder why you still are worried about the ringing.
Does the ringing cause a problem?
Klaus
Need to generate an auxiliary supply voltage in a 15 - 25 V range. You can copy some ideas from the high voltage output reference designs like der580.
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