This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LM5109B use

Other Parts Discussed in Thread: LM5109B

In figure 3 of the data sheet for LM5109B, I see that LM5109B can be used for a wide rage of switching frequencies (down to 1kHz). Can this be used with control inputs that switch very slowly (essentially dc)?  Example: Use 2 to control an H-bridge that sets the direction of a current through a coil for a constant magnetic field. 

Thanks for the help,

Robert Stickney

  • Hello Robert,

    Your understanding is correct. The two channels are independently controlled by INPUT. However, it must be guaranteed that VDD-VSS and VHB-VHS are always within the safe UVLO region. for example, VDD-VSS, VHB-VHS must be higher than 8V, which is the recommended minimum.

    That is why there is a minimum turn-on time for the bottom switch that the bootstrap cap can be refreshed and charged in most of the synchronous rectifier applications.

    Please feel free to let me know if you have further questions.

    Wei