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TLV9064: Device recommendation for appliance customer

Jade Han
Intellectual 1605 points
Part Number: TLV9064
Other Parts Discussed in Thread: TLV4172, OPA4396, OPA4397, OPA4196, OPA4197, TLV9054, TLV9004, TLV4171

Tool/software:

Hello experts,

Currently my customer is looking for IC with below spec, could you please check below and share any recommendation ICs?

  • application: BLDC motor speed control, looking for non-inverting amplifier
  • VDD: any DC voltage between 3.3V~15V range
  • VSP output: 0.6V~7A
  • Please find example circuit image as below

Since it is for motor control application, I thought maybe TLV9064 could work, could it?

Also, for BLDC motor speed control, are there any success history on the op amp as below image?

(blue: input voltage 3.3V, 1kHz / red: VSP output 0.6~7V)

 

  • 0
    TI__Guru 67601 points

    Jade,

    For supply voltage up to 5.5V, you could use any of the op amps like TLV9004, TLV9054, TLV9064, OPA4396 or OPA4397 BUT from 5.5V to 36V supply you would need to use TLV4171, TLV4172, OPA4196 or OPA4197.

    Having said that, the circuit as shown below, regardless of what op amp you use, has a very limited bandwidth of around 8Hz set by the R3||(C1+C2) - see below.

    Thus, the input signal would be severely attenuated by AC gain of 0.0175 - see below.

    Changing the output caps to 10nF will have fc of around 8kHz allowing you to pass the 1kHz signal without attenuation - see below.

  • 0 in reply to Marek Lis
    TI__Intellectual 1605 points

    Hi Marek,

    Thank you so much for your detailed reply. I discussed the application with customer, and it seems customer wants to input PWM, have PWM output, then use the R3//(C1+C2) filter to make it into DC voltage. They hope to change the output voltage by controlling input PWM's duty. This was why they had the RC filter at the end of the amp.

    I asked them to ask additional questions onto this forum, so I chaged the form from internal to public.

    Thank you for your help and support.

    Best regards,
    Jade

  • 0 in reply to Jade Han
    TI__Guru 67601 points

    OK.  Sounds good.