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TPS63700 goes shutdown mode when it is loaded for minimimum steady state current

Mariappan Subramani
Prodigy 10 points
Other Parts Discussed in Thread: TPS63700

We are using TPS63700 part for the 5V to -6V generation. We have designed the circuit for max current of 200mA and we have tested for the external resistive load for the max rating. It working fine. When I connect with the actual load of 60mA requirement, It get shutdown and not recovered till I switch off and ON again. When I try to power up my original circuit with external supplies , it hardly takes only 60mA current. By TPS63700 circuit is proved for 250mA supply current. But I am not able to work with original load.

1. Why this chip is going to shutdown mode ?

2. Why it is not recovered or trying to recover when it went to shutdown mode

3. What is the use of COMP pin capacitor ?

4. How can i increase the soft start current .

 

Please replay at the earliest

 

Regards

Mariappan

Hardware Design Engineer

044 47414020

mariappan.subramani@datapatterns.co.in

 

  • 0
    TI__Guru**** 166106 points

    Regarding 1 and 2, are you testing this on TI's EVM or on your own board?  Do you have a schematic and oscilloscope plots of the the part not starting up (Vin, SW, Vout, inductor current)?   Is the actual load highly capacitive or inductive?

    Regarding 3, the COMP capacitor is used to stabilize the internal control loop.

    Regarding 4, there is no simple way to increase the soft start using different passive components.  You could place a FET between the output capacitor and the actual load that more slowly connects the IC to the load.