LCS708HG problem
hi all
I have made a dc/dc converter with the lcs708(input dc 380v,output dc 130V/3A). All the design parameters
is according to the PI Expert to calculate . Now i have forbidden the ov/uv pin,then change the input constant
voltage(B+/B- pin).My question is the transformer whether need make air gap? I test the HB pin waveform ,i
think it is be out of shape ,but i dont know the reason.
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Comments
hi neela
Thanks for you suggestion. I have find the HB waveform problem, but i dont know the reason. As you said
when use the normal OV/UV resistor chain asrecommended ,the B+/B- voltage is cannot chang,according
to the file(hiperlcs_family_datasheetCN.pdf) the OV/UV pin is can forbiden.
I assume 1 waveform is HB waevform, what is the other waveform in your attchement? could you share with us your PIXL and schematic for debugging?
Your HB waveform has big ripple during turn on. For debug purpose, you can use the normal UV/OV resistor chain as recommended from PIXL. If waveform lools normal, then do addtional modification.