LM51770EVM-HV: How to measure Control Loop Response

Satoshi Ando

Part Number: LM51770EVM-HV
Other Parts Discussed in Thread: LM51770,

Hi, team,
This is Ando.

I'm planning to use LM5177x and design circuit.
In the document, EVM User's Guide: LM51770 LM51770 Buck-Boost Controller Evaluation Module, you show Control Loop Response.
How did you measure them?
I think you measure using FRA equipment, then, where do you set OSC point, input point and output point?

Best Regards,
ANDO Satoshi

13 days ago

0 Brigitte 12 days ago

TI__Guru 67140 points

Hello Ando,

LM51770EVM-HV has the right injection and measuring component populated. If you have a look at the schematic in the user's guide, right above the IC, you can find JP6 pins 1 and 2 as well as R45 for this.

At the end, we inject and measure on the feedback node.

For more details have a look at this power tip: Power Tips: How to set up a frequency response analyzer for Bode plot

Best regards,
Brigitte

Power management

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LM51770EVM-HV: How to measure Control Loop Response