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LM5035C: minimum pulse, pulse at DCM

Part Number: LM5035C

Tool/software:

Hello,

We are designing half bridge converter with LM5035C.

The below items are needed to design for us, please us know.

*minimum pulse

    Refer to datasheet, minimum dity is 0%. But how long is the minimum on time pulse which can be output?

*pulse at DCM.

    I understand this IC work as DCM mode at very light load.

    In the case of DCM mode, the number of HO and LO are the same? We hope that these each number are the same to avoid unbalance of high side and low side capacitor of half bridge.

    If these each number are not same, do you have any suggestion to avoid unbalance of high side and low side capacitor of half bridge.

   (the below drawing is HO or LO, we hope left waveform, want to avoid right waveform.)

    

  • Hi,

    Minimum PWM pulse is typically 80ns. 

    This device does not have two adjacent pulse width match. In voltage mode control half bridge converter the volt seconds balance is achieved automatically, i.e., longer pulse discharge more half bridge capacitor so time x volt is adjusted to the short pulse but it’s half bridge capacitor discharges less.

    You can also add dc flux blocking capacitors in series with the transformer winding to make flux balance.

  • Thank you for your description and suggetion.