Dear Community,
We are developing a power supply that provides 2 power rails, an +70V and a -70V power rails. Both rails should be able to provide some power, around 1 Amp. per rails.
We developed the schematic and selected the components using both Webbench and the Excel-sheet provided by Texas Instruments.
So our input is 220VAC, which is rectified to ~310VDC (with ripple).
Our desired output is +/- 70V (2 rails, total voltage difference of 140V).
We are using a self-made transformer for testing purposes, just to see if the schematic works. The winding of the transformer is: Primary: 10; Secondary 5:5 (Center tap is signal ground); Bias: 1
Our result is no power, and a strange hiccup signal on both the output as on the HO & LO output pin of the UCC256304.
The hiccup signal looks like a 300VDC with som dips to 0V, for a time period of a couple ms.
I added the schematic in the attachment. If you can't open it, please let me know so I can send the schematic in a private message or e-mail.
Also, can you give some advise how I can measure the signals on the power supply using an oscilloscope? The ground reference of the oscilloscope is connected to his internal PE, but the GND on the power supply is not, so if I would connect those two, the Earth Circuit Breaker would kick in. Is there a smart way to measure the signals with oscilloscope? A colleague told me to place a 1:1 isolation transformer before the input. Is this the only solution?
With kind regards,
Sergio van Vliet
