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DRV110: DRV110 (DRV103) solenoid drive with galvanic insulation

Davide Arzarello
Prodigy 100 points
Part Number: DRV110
Other Parts Discussed in Thread: DRV103, UCC28740, ISO1212

Hi I would like to use the DRV110 or DRV103 (with external power mosfet) to drive and AC 110/220 solenoid valve

The application note circuit are quite well explained but all schematic has NO galvanic insulation from the AC Load

Since the controller that drives the PWM current controller has some sensor, a GUI and buttons I'm little bit worried but a direct path to AC

Is there any way to insulate the AC part from the rest?

2nd question, what is the suggested frequency for a solenoid valve or linear actuator control via PWM ??

thanks

Davide

  • 0
    TI__Intellectual 1965 points

    Hi Davide,

    Thanks for your question. Let me contact the expert who supports this part. You can expect a response by 1/17/20.

    Best,

    Grant

  • 0 in reply to Grant Falkenburg
    Prodigy 100 points

    While waiting for expert suggestions just attach the schema from application notes that I use for reference and where I have the concern in galvanic insulation of the AC part towards the uController part

    sure of your support

    br

    Davide

  • 0 in reply to Davide Arzarello
    Prodigy 100 points

    Hi any chance to get a support and feedback on how to achieve galvanic insulation in high voltage AC pwm driver circuit?

    Br

    Davide

  • 0 in reply to Davide Arzarello
    TI__Intellectual 1965 points

    Hi Davide,

    Let me contact the expert again. I believe he was on business travel last week. My apologies for not recognizing this earlier.

    Best,

    Grant

  • 0 in reply to Davide Arzarello
    TI__Expert 4940 points

    Hi Davide,

    DRV110 PWM frequency can be set up to 27kHz, optimum frequency depends on system conditions: solenoid inductance and resistance, system noise, solenoid voltage headroom, Ipeak , Ihold ...  One potential system issue is the solenoid acoustic noise, increasing PWM frequency may help

    The system needs AC to DC galvanic isolation, one solution is to use a isolated AC to DC controller 

    Regards,

    Costin

  • 0 in reply to Costin Cazana
    Prodigy 100 points

    Hi Costin

    thanks for you answer and support

    about frequency I understood will depends from many factors coming from the controlled valve...I need to build a "general" purpose controller for multiple valve/actuator models so need to finda a compromise and average value.  If I understand well the the most common range is around 20-25-KHZ, lower frequency can create some noise right ?

    About galvanic insulation non clear to me how to achieve "isolated AC to DC controller" 

    uController will be powered by AC/DC converter (3.3 or 5V) and the GND will be common with the power mosfet GND so when mosfet is closed the control part is connected to main power supply

    Can you help me with a block diagram on how to achieve the insulation ? where you suggest to cut the circuit and introduce optocoupler?

     

    Thanks again

    Davide

  • 0 in reply to Davide Arzarello
    TI__Expert 4940 points

    Hi Davide,

     DRV110 technical documents has an block diagram with isolation:

    TIDA-010071 Schematic and Block Diagram

    Please check ti.com isolation to find the best fit device for you application.

    20kHz-25kHz is a safe solution, if that's enough headroom across the solenoid for both Peak and Hold.

    Marginal Peak solenoid supply headroom can force PWM >100%, this low frequency causing audible noise.

    Same think may happened during hold. A low enough headroom will force peak to DC, and hold PWM intermittently >100%

    Regards,

    Costin

     

  • 0 in reply to Costin Cazana
    Prodigy 100 points

    Costin Cazana said:

    Hi Davide,

     DRV110 technical documents has an block diagram with isolation:

    TIDA-010071 Schematic and Block Diagram

    Please check ti.com isolation to find the best fit device for you application.

    Schema you share the DRV110V is pwered by 13V DC so no need for any galvanic insulation from the controller 

    Any way to get galvanic insulation for a AC 110/220V solenoid valve control ?

    Davide

  • 0 in reply to Davide Arzarello
    TI__Expert 4940 points

    Hi Davide,

    The example provide galvanic isolation  AC to DC supply forDRV110 and rest of the analog circuit. 

    In case valve needs  high voltage , the AC transformer will provide the isolation if is not share by other circuits.

    As you mention, on your schematic one critical patch is the external digital controller that needs to have galvanic isolation.

    You'll need to add a digital type isolator between external controller and DRV110.Please check ti.com "isolator", most likely you'll find

    a device to fit your needs.

    The previous example has two isolations:

    -DC supply : UCC28740 

    - Digital : ISO1212

    Regards,

    Costin