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TPS61046: Current Limit Questions

Part Number: TPS61046

Hello E2E,

I have a customer using the TPS61046 in a 3.3V to 12V boost configuration. In the datasheet, the “peak switch current limit” is specified min(600mA).

How is this peak current limit implemented? Does it look for any instance above the limit or does it need a certain number of cycles/peaks above the limit? What happens when the peak current goes above the limit?

My customer is seeing peaks above the 600mA minimum peak limit spec (around ~620mA). They can not make schematic changes at this point but they need to asses the risk of going above the current limit.  Any information you can provide on how the current limit is working internally is much appreciated.

Russell

  • Hi Russel:

    The 600mA is the minimum limit. 

    For each switching beginning, the low side switch will turn on. Then the current of the inductance rises. Once it hit the current limit, it will turn off. And wait for next cycle. 

    So if the load is heavy and exceed the limit, the converter can't supply the right current needed. The Vout will drop. 

    If the Vout drops too much, it will enter into short current protection. Details can be checked in the datasheet.