TPS4811-Q1: Working with motors ( back EMF problems )

Meori Mizrahi

Part Number: TPS4811-Q1
Other Parts Discussed in Thread: TPS48110Q1EVM, LM74930-Q1

Hi Team

We consider working with the TPS4811-Q1 for protecting servo motors ( 48VDC) that used in our application

For testing it we connect the TPS48110Q1EVM ( evaluation board from TI ) to one motor. see the below scheme

during test this circuit and validate its well action - disconnect the load at the desired threshold 8A after 1 sec, see below curves

blue - output voltage

yellow - output current ( current prove 10mv/1A)

the TPS48110-Q1 damaged and stop function.

I assume due to reverse current as you can see the little negative yellow hill

is it true ? how can I protect it from reverse current ?

over 1 year ago

0 Rakesh over 1 year ago

TI__Guru** 105361 points

Hi Mizrahi,

Can you check whether CS+ and CS- voltage is violating the data sheet spec.

Is failure repeatable ?

Please measure pin to pin impedances and pin to ground impedance and share us to get better understanding

Best regards

Rakesh

0 Meori Mizrahi over 1 year ago in reply to Rakesh

Prodigy 40 points

Hi Rakesh

I can't do it, because i already replaced this TPS with new device

In the mean time, i work on this solution below

1) diode for blocking reverse current that might damage the device

2) diode for allow current flowing path for reverse current that absorb by chopper and break resistor that located before this circuit

please give your comments

0 Rakesh over 1 year ago in reply to Meori Mizrahi

TI__Guru** 105361 points

Hi Mizrahi,

I don't see any concern. The power loss in the diode could be challenge to manage at 8A - if yes, consider using ORing controller like LM5050 to replace diode.

Also, we have LM74930-Q1 which has reverse current ON/OFF feature. Please have a look and let me know,

Best regards

Rakesh

0 Meori Mizrahi over 1 year ago in reply to Rakesh

Prodigy 40 points

Hi Rakesh

thanks for your comment, we will consider it

can you recommend on circuit that implement chopper for break resistor ( our power supply does not have sink ability ) ?

0 Meori Mizrahi over 1 year ago in reply to Meori Mizrahi

Prodigy 40 points

Hi Rakesh

still waiting to hear from you new ideas for creak chopper

thanks

0 Rakesh over 1 year ago in reply to Meori Mizrahi

TI__Guru** 105361 points

Hi Mizrahi,

Sorry, I don't have idea on that implementation.

Best Regards,

Rakesh

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TPS4811-Q1: Working with motors ( back EMF problems )