TPS61022: Use of feedback pin at an unconventional point

Jomon

Part Number: TPS61022
Other Parts Discussed in Thread: TPS22810,

I have a TPS61022 boost regulator for 5.1V. At the regulator output, I have a TPS22810 load switch. I need about 5.1V at the output of the load switch. Since the load switch has a small resistance of few milli ohms, there is a slight decrease in voltage. This voltage drop varies with current.

So, my query is, whether it is OK to keep the feedback of TPS61022 at the output of TPS22810 so that this drop of voltage is automatically compensated as TPS61022 will try to regulate TPS22810 output voltage to 5.1V ?

over 1 year ago

+1 Brigitte over 1 year ago

TI__Guru 65170 points

Hello Jomon,

The biggest problem you will have with this approach is to make sure that the TPS61022 is never operating with the feedback divider disconnected because of the load switch. If this happens, FB is fixed to GND and then the device will most probable damage itself by increasing the output voltage to as high as it can which is most probable too high for the device to survive.

I would recommend using a resistor divider at the output of the TPS61022 and create a voltage that is higher than the maximum voltage you need behind the load switch and then manipulate the FB pin with one of the methods described in these articles of having a second lower impedance FB divider behind the load switch. The second solution is not tested.

Adjusting VOUT in USB Type-C and wireless charging applications, part 1

Adjusting VOUT in USB Type-C and wireless charging applications, part 2

Best regards,
Brigitte

Power management

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TPS61022: Use of feedback pin at an unconventional point