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Suggestion for adequate PWM controller IC for small solenoid 24VDC valve

Stefano Alfredo La Spina
Prodigy 210 points
Other Parts Discussed in Thread: DRV110, DRV8904-Q1, DRV8932

Hi forum.

I need to drive a small solenoid valve that operates at 24VDC 10W in a continuous selectable frequency range from 1 to 250Hz PWM frequency with a selectable duty cycle from 2-100%.

PWM frequency is relatively low, but I need to vary it together with the duty cycle.

I explain: Duty Cycle controls the percentage of time that the valve is ON within a given cycle period: consider for example 150 Hz (cycles/second). (1) At a 50% duty cycle, the valve will be ON for 3.3 msec and will be OFF for 3.3 msec. I need to control this accurately.

Is there an IC that maybe has multiple outputs like the DRV110?

Any help appreciated,

best regards

  • 0
    TI__Mastermind 37683 points

    Hello Stefano,

    Are you looking for a driver with integrated PWM generators that cover the frequency and duty cycle that you need? If so, we don't have any drivers with this exact capability. 

    Do you required PEAK and HOLD current regulation? Essentially adjustable current regulation during PEAK and HOLD periods?

    How many valves do you need to drive?

    Regards,

    Pablo Armet

  • 0 in reply to Pablo Armet
    Prodigy 210 points

    Thanks Pablo for the fast reply.

    Yes would be preferable having all the features. especially the frequency and duty cycle. but I can maybe separate it in two different IC's. PWM generator and output driver.

    Actually no Peak and Hold is not mandatory. 2 outputs or even 4 would be preferable but especially the first feature is mandatory.

    Thanks again.

  • 0 in reply to Stefano Alfredo La Spina
    TI__Mastermind 37683 points

    Stefano,

    Stefano Alfredo La Spina said:
    Yes would be preferable having all the features. especially the frequency and duty cycle. but I can maybe separate it in two different IC's. PWM generator and output driver.

    Unfortunately we don't have a driver with this capability. The only one that is close is the DRV890x-Q1 family of multichannel drivers. The DRV8904-Q1 is the 4 channel driver. This device comes with integrated PWM generator but has a max frequency of 2kHz.

    One option is to use the DRV8932 with addition of a PWM generator from an MCU or other external IC. Let me know if this device fits in your design.

    Out of curiosity, why is integrated pwm generator a mandatory feature you need? Is it to save up timer channels on your MCU?

    Regards,

    Pablo Armet

  • 0 in reply to Pablo Armet
    Prodigy 210 points

    Pablo, thanks again.

    will look to the suggested IC's. By the way why do you say "PWM frequency maximum 2kHz." I need it way less up to 250 Hz.

    Yes we were thinking of modular all-in-one boards so one MCU can control via SPI a bunch of them without sharing the PWM resource of the single MCU.

    Cuold you please suggest me as You say external PWM generators? in order to follow the Generator + Driver IC?

    best regards and thanks again

    Stefano

  • 0 in reply to Stefano Alfredo La Spina
    TI__Mastermind 37683 points

    Stefano,

    Stefano Alfredo La Spina said:
    "PWM frequency maximum 2kHz." I need it way less up to 250 Hz.

    Sorry I read too fast and thought you wrote 250kHz. In that case, the DRV8904-Q1 is a good option. It can be controlled purely via SPI. 

    If this drivers works for your application needs, the DRV8904-Q1 is a good option. For higher current ratings, the outputs can be paralleled to achieve higher current capability. 

    Regards,

    Pablo Armet

  • 0 in reply to Pablo Armet
    Prodigy 210 points

    Thanks Pablo. Have seen the datasheet for the IC you proposed but one thing is unclear. the specs say:"User has the flexibility to select the PWM frequency of channels out of 4 settings of 80-Hz, 100-Hz, 200-Hz and 2-kHz...." but I need to be able to choose in a continuous way from 1 to 250Hz in 1 step. This is mandatory for my application. Could you please suggest other ways to implement it? Thanks a lot for the patience.  Steff

  • 0 in reply to Stefano Alfredo La Spina
    TI__Guru 54695 points

    Stefano,

    The DRV8904-Q1 won't work like that.  It has no external PWM inputs, so frequency is fixed with selectable options.  You would need to consider a device with external PWM inputs to allow this type of frequency and duty cycle control.  

    Something like the DRV8932 would work for you.

    https://www.ti.com/product/DRV8932

    Regards,

    Ryan

  • 0 in reply to Ryan Kehr
    Prodigy 210 points

    Thanks Ryan. Will look at. Could You please suggest me also a IC PWM controller suited for my needs?

    Best regards and thank You

  • 0 in reply to Stefano Alfredo La Spina
    TI__Mastermind 37683 points

    Stefano,

    Any simple PWM controller will work in your case (as long as it go down to 1Hz). An MCU with PWM generator will be the best option. 

    I'm not an MCU expert so I recommend posting to the MCU forum for help choosing your controller.

    Regards,

    Pablo Armet