Other Parts Discussed in Thread: LM5176EVM-HP, LM5176
Hello.
I have modified an LM5176EVM-HP evaluation board to have an output of 24V /3A, with an input range of 12V-32V.
I have replaced capacitors/mosfets/ self/ resitors, etc..
It works fine, but the ripple is increased when the voltage is more than 29V.
I put probes on the 4 gates of the mosfets to analyse the behaviour of the LM5176.
When the input is about 20V, the controler is in boost region=> oscillogramme seems to be OK.
When the input is about 24V, the controler is in buck-boost region=> oscillogramme seem to be OK.
When the input is about 28V,he controler is still in buck-boost region=> is it normal?
When the input is about 32V, the oscillogramme seems to be strange:
- the duty cycle is not constant.
- HDRV2 et LDRE2 are not at a constant level (like in a buck mode). Is this behaviour normal?
Best Regards.
Sylvain
