TPSF12C1: Measuring Loop Gain characteristics

Hirotsugu Kobayashi

Part Number: TPSF12C1

Hi team,

Where should I insert the injection resistor when using FRA to adjust the loop gain characteristics?

Since the injection is on the N side, I am thinking of inserting an injection resistor between the CSENS2 and SENSE2A/2B terminals, is this correct?

Best regards,

8 months ago

0 Timothy Hegarty 8 months ago

TI__Guru 59837 points

Hi Kobata-san,

It's not possible to measure the loop gain with the standard IC, as you need access to the amplifier inverting terminal with the feeback network unconnected). Recommendation is to verify the stabilty with the quickstart calculator or the SIMPLIS simulation model.

Regards,

Tim

0 Hirotsugu Kobayashi 8 months ago in reply to Timothy Hegarty

Mastermind 9055 points

Hi Tim-san,

I'm concerned about the effects of parasitic capacitance, etc., but does that mean I can't make adjustments while checking on the actual machine?
It seems that the characteristics of the SIMPLIS model are measured using COMP2 and STAB, but what is STAB?

Best regards,

0 Timothy Hegarty 8 months ago in reply to Hirotsugu Kobayashi

TI__Guru 59837 points

Hi Kobayashi-san,

STAB is effectively the amplifer inverting input, which allows insertion of an excitation source at the appropriate position for loop gain measurement.

Regards,

Tim

0 Hirotsugu Kobayashi 8 months ago in reply to Timothy Hegarty

Mastermind 9055 points

Hi Tim-san,

I understood as below, is it correct?

In the simulation, signals can be injected from STAB, but in the actual device there is no corresponding terminal, so it cannot be measured.

+1 Timothy Hegarty 8 months ago in reply to Hirotsugu Kobayashi

TI__Guru 59837 points

Yes, that's correct.

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TPSF12C1: Measuring Loop Gain characteristics