Inductor DCR Current Sensing

Marcin Kuczma1

Other Parts Discussed in Thread: INA169

Hi, I am designing a buck converter with mosfet half bridge, supply voltage 130 V and output voltage regulated from 0V to 125V. I want to measure output current from the inductor Rdc voltage like this:

For now I do not know how to shift voltage across C1 to voltage refereced to ground. My question is: Is it possible to use for it any of your Hi Side Current Amplifiers like INA169 with PNP output level shifter. I tried to simulate that circuit in TinaTI with some Current amplifiers without good results.

over 5 years ago

0 Javier Contreras4 over 5 years ago

TI__Mastermind 32140 points

Hello Marcin,

I think with regards to the high voltage measurements you may want to take a look at http://www.ti.com/lit/an/sboa295/sboa295.pdf or http://www.ti.com/tool/TIDA-00332 to assist you.

With regard to you sensing location on the circuit diagram you listed. You may want to make modifications. First you inductor is included in your measurement and I am sure that resistance will vary and will not be specified very well in regards to its resistance. Also your R10 and R2 will cause issues with the accuracy of your measurements. This is due to the input bias currents and not being matched as well.

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Inductor DCR Current Sensing