TPS61288: Loop Bode Plot

Morgan Novak

Part Number: TPS61288
Other Parts Discussed in Thread: PMP40909

Tool/software:

Hello

Hello,

I am designing a circuit using the TPS61288 calculation tool. What is my target goal for loop-bode plot? Gain margin? Phase Margin?

I took the schematic from PMP40909 and input it into the tool and I get the following result:

Did I input something wrong? Is this what the loop bode plot is supposed to look like?

0 Fergus He 11 months ago

Hi Morgan,

Here some points:

1. the inductor current is too high and the peak current for TPS61288 is 15A, please halve the load current when calculate.

2. the feedforward frequency should be 1e7 kHz(Positive infinity), the feed forward capacitor is not used in schematic.

3. For the Bode Plot, the phase margin should be over 45deg and gain Margin should be over 10dB.

In your design, the phase waveform does not go through 0deg so that the tool presents a wrong number.

Please refer to below document for a normal bode plot analysis.

Best Regards,

Fergus