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TPL0102-100: Potentiometer and a timer

Farzaneh Faridi
Intellectual 585 points
Part Number: TPL0102-100
Other Parts Discussed in Thread: TLC555

Dear TI Members,

I'm currently designing a circuit to detect output voltage ripple and need your assistance in selecting the appropriate potentiometer and timer. Here's a brief overview of my requirements:

I have two different outputs:
1. Vout1 = 48V DC with a permissible ripple of 30mVpp
2. Vout2 = 125V DC with a permissible ripple of 2.5Vpp

The circuit should detect when the ripple exceeds these specified values and, after a certain period, activate an alarm. Initially, I considered using standard potentiometers, but I have since discovered digital potentiometers and believe they might be a better fit for this application. Additionally, I need to incorporate a timer into the circuit.

I reviewed some of your products but couldn't make a selection due to my limited experience with these components. Could you please recommend suitable digital potentiometers and timers that would work well for my project?

Thank you in advance for your assistance.

Best regards,

Farzaneh

  • 0
    TI__Mastermind 31598 points

    Hello,

    I'm reviewing this now and will get back to you shortly.

    Best,

    Katlynne Jones

  • 0 in reply to Katlynne Jones
    TI__Mastermind 31598 points

    Hi Farzaneh,

    To start, pretty much all of our digital potentiometers have an input voltage range of ~0 to 5V. Some have a negative range such as the TPL0102-100 that you linked. 

    You would need to first divide down the voltage of your two outputs before they could be connected to any of our digital potentiometers. In addition, you need a comparator to actually detect the ripple, right? If you were planning to detect this with the potentiometer, please let me know by sharing a block diagram.  

    Best,

    Katlynne Jones

  • 0 in reply to Katlynne Jones
    Intellectual 585 points

    Dear Katlynne,

    I could make the circuit and according to the simulations it works properly.

    I have designed a ripple detector circuit that monitors ripple voltages and detects when the peak-to-peak ripple voltage exceeds 30mV. The final stage of this circuit is a comparator, which outputs a constant "1" when ripple is detected and "0" when there is no ripple.

    Now, I want to add a timer that will activate an alarm if the ripple persists for more than 20 seconds. I attempted to use a 555 timer for this purpose, but I am unsure how to trigger it correctly given that the comparator output is either always "1" or "0".

    I would greatly appreciate any help or suggestions on how to achieve this.

  • 0 in reply to Farzaneh Faridi
    TI__Mastermind 31598 points

    Hi Farzaneh,

    I'm looping in the team responsible for the 555 timers. If you look at the TLC555 datasheet, there are descriptions for using the device in monostable mode which can create trigger a 20 second timer when your comparator output changes. You would need additional logic to determine that the comparator output is still high when the 20 seconds has passed. 

    Best,

    Katlynne Jones

  • +1 in reply to Katlynne Jones
    Intellectual 585 points

    Katlynne,

    Thanks for all your support. I have done the timer using CD4060.

    Regards

    Farzaneh