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operational amplifier for relè

Prodigy 120 points

Replies: 19

Views: 147

Ciao a tutti.
sono alla ricerca di amplificatori operazionali in grado di pilotare sei relè bistabili a bobina singola, non tutti insieme ma separatamente. in questi relè la corrente scorre in entrambe le direzioni.
Ho bisogno di amplificatori operazionali in grado di sopportare la corrente necessaria (un impulso) ma soprattutto la sovratensione generata dalla bobina del relè quando è spenta poiché non posso applicare un diodo di protezione in parallelo alla bobina del relè.

  • Hi everyone.
    they are looking for operational amplifiers capable of driving six bistable single coil relays, not all together but separately. in these relays the current flows in both directions.
    I need operational amplifiers able to withstand the necessary current (an impulse) but above all the overvoltage generated by the relay coil when it is turned off since I cannot apply a protection diode in parallel to the relay coil.

  • In reply to luigi coffani:

    Ciao Luigi,

    can you tell some details on the relais? Does each relais consist of two seperated coils? Do you have a datasheet?

    Kai

  • In reply to kai klaas69:

    no . these relays only have one coil but the current flows in both directions.
    I have not yet chosen which relay but I think the amount of current in mA is similar to that of the other relays.

  • In reply to luigi coffani:

    Hello Luigi,

    If you have a dual supply where each half has enough voltage to run the relay then a push/pull peripheral driver would work well. With a single supply an H driver is needed. H driver is more common. For low cost there is DRV8837. For easy PDIP testing there is L293D. 

    This could be done with an op amp, just like a wrench can be used as a hammer.

    Regards,
    Ronald Michallick
    Linear Applications

    TI assumes no liability for applications assistance or customer product design. Customer is fully responsible for all design decisions and engineering with regard to its products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning Customer's design. If Customer desires engineering services, the Customer should rely on its retained employees and consultants and/or procure engineering services from a licensed professional engineer (LPE).

     

  • In reply to Ron Michallick:

    Hi Luigi,

    In addition to the DRV8837, the DRV8837C is another option available.

    Best Regards,
    Rick Duncan
    Motor Applications Team

  • In reply to Rick Duncan:

    thanks for the replies. the H bridges that I know need at least two distinct commands but I have only one (high or low state deriving from the outputs of the 40193) which is why I had thought of an operational amplifier configured as a buffer. of course I had already thought of making a dual power supply with a central socket transformer and a double capacitor voltage divider in order to supply power to the two 40193 (5 volts) and operational amplifiers (15 volts) whose input is connected at the exit of 40193. two 40193 six outputs that go to six operational amplifiers but what worries me is the overvoltage created by the coil at shutdown. quidi? do you recommend a push / pull? for example ?

  • In reply to luigi coffani:

    Luigi,

    A bistable relay has three input states [set, clear, hold]. That takes 2 binary bits, or a trinary signal [low, center, high].  

    What does your control signal look like?

    Regards,
    Ronald Michallick
    Linear Applications

    TI assumes no liability for applications assistance or customer product design. Customer is fully responsible for all design decisions and engineering with regard to its products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning Customer's design. If Customer desires engineering services, the Customer should rely on its retained employees and consultants and/or procure engineering services from a licensed professional engineer (LPE).

     

  • In reply to Ron Michallick:

    I don't know which type of relay you are referring to.
    maybe it's better that I attach a scheme as soon as I can

  • In reply to luigi coffani:

    in a simplified way

  • In reply to luigi coffani:

    no opinion ?