LM5170EVM-BIDIR: Output voltage regulation

Raj B

Other Parts Discussed in Thread: LM5170

I tried for buck mode and apply 24V DC at HV port and electronic load at LV port. The analog loop is set for 14.35V (refer schematic), The brake circuit works fine and I got at output voltage. I got 19V Dc output voltage that is not stable it fluctuate 18.5 +/-0.5V (waveforms are attached in PDF file)

Pls refer PDF file and suggest how to make voltage loop stable.

Regards,

RajB

LM5170_voltage loop.pdf

4 months ago

0 Feng Ji 4 months ago

TI__Mastermind 18065 points

Hi Raj,

Please discuss only one question in one thread.

What is the load condition? No load?

Please share the waveforms of U2B pin 5,6,7.

Best Regards,

Feng

0 Raj B 4 months ago in reply to Feng Ji

Prodigy 55 points

LM5170_Analog loop waveforms.pdf

Hi Feng,

PFA waveforms of U2B Pin 5,6,7.

Best Regards,

Raj B

0 Feng Ji 4 months ago in reply to Raj B

TI__Mastermind 18065 points

Hi Raj,

Please check why U2B Pin 5,6 show 0V.

Best Regards,

Feng

0 Raj B 4 months ago in reply to Feng Ji

Prodigy 55 points

Hi Feng,

Thank you for your support. I removed R89 & R87 (95.3K) from the analog section. I got output regulation. Then I changed the resistor value of R75 to 23K, I got Output voltage 24V at HV port and regulation is also maintained(checked upto 10A). with help of microcontroller I Set Master enable (UVLO), EN1 (channel1), EN2 (channel2) and control DIR =1 & 0 , I could control the BIDIRECTIONAL buck boost mode successfully.

Regards,

RajB

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LM5170EVM-BIDIR: Output voltage regulation