TOP259EN Voltage drops with load
Hello,
I did a project using PI expert with TOP259EN, I did as projected and now I am testing the power supply.
The power supply should deliver 10A/12V.
With a light load (300 ohms), it delivers 12.04V, but when I try to use heavier loads, the voltage goes to zero. When it goes to zero, I see that each 2~3 secs, it rises a little bit, till 3~4V but then it goes back to zero. using osciloscope, I see that the TOP259 tries to switch the FET (when the voltage rises, as I said earlier).
I searched already in the forum / applications note but I didn't found any solution.
Could you please help me?
George Razera
Comments
Hi i think i have the same problem
you find in this doxument all my result
| Attachment | Size |
|---|---|
| smps.pdf (192.87 KB) | 192.87 KB |
Hi hicham,
Can you give us more information of your testing like what input voltage and load current you used?
Regards,
Jedidiah
hi PI-Jedidiah
input voltage is 230 Vac
but about the load i have no load
thanks PI-Jedidiah
Hi hicham,
Can you measure the Drain to source voltage together with the output diode anode to cathode voltage? Please have the two measurements measured in one oscilloscope data only.
Regards,
Jedidiah
Hi RazeraG,
Can you share the PI expert file (with computation) you used in your design? Can you also check the waveform on Control pin? Let's check if it doesn't reached as low as 4.8V when you apply load.
Regards,
Jedidiah