TPS54302: Voltage drop consistently when acting a power source of servo motor

Jacfger Fung

Part Number: TPS54302

Hi,

As the title said, I used tps54302 to power a servo. However, it seems that whenever the servo move, the voltage will drop and raise and the servo start behaving weirdly (like swinging back and forth consistently).

I was thinking if the IC wasn't fast enough to respond the change in the load or something.

I wonder what should I look at from the datasheet next time (transient response or anything ?) when choosing a regulator for any purpose (e.g. powering an MCU, development board or motor anything like that) ?

Best regards,
Jack

over 4 years ago

0 Shawn Nie over 4 years ago

TI__Genius 10070 points

Hi,

Could you please also share the schematic and waveform？

And for the layout, it is bad to place SW trace under the IC, the switching noise is easy to be introduced to FB, the system may be unstable.

Shawn

0 Jacfger Fung over 4 years ago in reply to Shawn Nie

Prodigy 50 points

Hi,

This is the voltage output of the TPS54302.

Best regards,
Jack

0 Ryan Hu (BSR-MV) over 4 years ago in reply to Jacfger Fung

TI__Expert 4035 points

Hi Jack,

Just as Shawn mentioned above, the SW trace is under IC which is too close to FB pin, The FB pin is easy to be coupled by SW noise. Also I found the feedback resistor network is near to the inductor, the same SW noise concern to FB pin. Your problem is more likely due to the above reason.

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TPS54302: Voltage drop consistently when acting a power source of servo motor