TPS40090: Using LTC6101HV for current sense

DANIEL DALTON

Part Number: TPS40090

I am using the TPS40090 to regulate a 4 phase output 50V at 40A and 66V in. To sense current, using the LTC6101 to reference the inductor current to ground. I am unable to get stable performance. Tried adding additional ramp input to current sense. Works ok voltage mode (current sense shorted to gnd). Any problem using the LTC6101HV?

over 6 years ago

0 Qian Chen over 6 years ago

TI__Mastermind 24075 points

Hi Daniel,

Can you provide schematic in pdf file, so we can take a look?

Thanks

Qian

0 DANIEL DALTON over 6 years ago in reply to Qian Chen

Prodigy 30 points

708531-01 Rev - 9 20 18 Mark up.pdfQian

Here is schematic again. Sent a few days ago via company email but got no response.

Thanks

Dan

0 Qian Chen over 6 years ago in reply to DANIEL DALTON

TI__Mastermind 24075 points

Hi Daniel,

Sorry, I just searched my email box and did not find email from you. Not sure what happened.
The idea of using LTC6101HV for current sense looks fine to me.

Below are additional information and a few things to check.
1. With addition ramp, the converter is stable now. Can you check LTC6101HV output signal separately to see if it looks normal? Please check if there is noise on this signal.
Be aware the maximum differential voltage between CSx and CSCN is +/-100mV.

2. Without adding additional ramp, is the converter unstable at any condition or certain condition? Are you able to measure the bode plot?

3. TPS40090 has internal 500mV ramp for slope compensation. Usually external slop compensation is not needed.

Thanks
Qian

0 Qian Chen over 6 years ago in reply to Qian Chen

TI__Mastermind 24075 points

Hi Daniel,

I just sent a message with my email address.
Let's continute the discussion by email.

Thanks
Qian

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TPS40090: Using LTC6101HV for current sense