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LM5175EVM: LM5175EVM Question

Part Number: LM5175EVM

Hi Expert

as below discussion, VIN=11.3V~11.7V, 12.4V~12.8V, 14.3V~15V the reason for the signal not consist that the value of Cslope.

LM5175EVM: gate driver signal not consist - Power management forum - Power management - TI E2E support forums

After we reduced Cslope from 100pf to 22pf, this issue was resolved.

but in our tested: Fsw=300K output=12V/6A CS resister=5ohm Cslope=22pF:

when input voltage up to 29.5V,output voltage will up to 13V starting OVP that will lead to EVM in the hiccup mode

when input further up to 32V  vout will shunt down that mean doesn't have any output.

so could you please help to analysis what the reason of above situation?.

below picture is show the above two cases:

the 1 is : 29.5V output will up to 13V:

the other is 32V output none:

in addition, base on before discussion, we have two question as below:

  1. In the case of not consist waves, the on-time duty cycle of BOOST downtube and BUCK downtube is less than 50%. Theoretically, the duty cycle is less than 50%, and there will be no large and small waves without the participation of slope compensation. Why is there a relationship between big and small waves and Cslope?

2. If the not consist waves are caused by noise, please analyze how the noise came from? How does Cslope avoid the influence of noise?