lm5102 problem top mosfet out (HO) is not swtiching


I am using LM5102. 50Khz signal is given as input for tOP mosfet and inverted 50khz signal is given as input for botom mosfet. 

In the above circuit pin 4(HS) should connect to junction where top mosfet source and bottom mosfet drain connect. It is missed here but connected in hardware with a jumper. But the pin out HO (pin no 3) is not switching according to the input and at the same time there is switching at bottom output LO(pin no 10). Kindly helpme out whats wrong going on in the above circuit.

1 Reply

  • Hi Rajkumar,

    The circuit looks fine except that HS should be connected to F_Out as you have noticed. I would suggest you check the voltage across HB and HS to make sure there is sufficient bias for the high-side driver. Also check the HS voltage with reference to AGND. Bootstrap capacitor is charged when the HS is pulled low. 


    Min Chen