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OPA2350: OPA2350 How to work in DRV8412 refernce design?

Prodigy 40 points

Replies: 1

Views: 93

Part Number: OPA2350

Hi , i'am using  drv8412 reference design rev.g -> dual dc or step motor driver / below is the link

www.ti.com/.../TIDM-THREEPHASE-BSDC

When i test about this evm , i wondered about current sensing of motor

i attatch the schematic.


I know IA-FB ~ ID-FB is current feedbacks used by OPA2350EA

below, i have a some question Pleas, reply so detail as you as possible

1. How to Calculate about realtime Current?(Please example calculation Ex, Busvoltage24V and sample current 4amphear ) and what is the OPA2350 Gain? and DC Bias 2.5V voltage?

2. I dont  understand R26/R54/R35/R30/R64 work? how to use that for make to gain? or DC Bias? did it work inverting amp? calculate please(i think that chips operate as Low side motor current sensig)


I don't good at making english sentences , please Reply THankyou!

1 Reply

  • For DC gain, neglect all of the capacitors and only consider resistor values. Here is example how to do it for top op amp configuration:

    The real time current will be a function of frequency and thus will vary.  Thus, the best way is to measure the current or gain is to use one of the simulators like Tina-TI - follow the link for free download: 

    I have also attached Tina-TI schematic  - see below.

    OPA2350 Gain.TSC

    Marek Lis, MGTS
    Sr Application Engineer
    Precision Analog - TI Tucson

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