hello, we used the 5V input and wish to get the 1V output by using the TPS54620. But when I check the output , I found it is the 1.1V. so I changed the risisters R1&R2.
And the output is not varying and keeping the 1.1V. is the schematic wrong? I did it by the SwitcherPro. Then I change the another chip, it's nothing to help.
anything else I did not notice? what is the reason that i can't change the output by select the various risisters?
the other hand , is the chip is easy to broken if I have a fault connection? I have already changed sevral ones.
Can you post your schematic? Also waveforms including Vout and PH.
John Tucker
Consumer DC/DC Applications
thank you John,
I just measured it by the circuit tester.
I can't really read your schematic. It is a bitmap. Camn you post it as a PDF?
4657.base_board.pdf
hello, today ,I have test the waveform.
What are teh waveforms of the 3 shots? It is best if you can supply Vout and PH on the same screen. Set the timebase so I can make out the individual pulses. Also it would be good to see a start up waveform. If you are trying to get 1.0 V and instead get 1.1 V, and changing the resistor divider does not affect the output voltage, you may have a leakage voltage from another circuit appearing at your output.