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LM74610-Q1: About power consumption

Part Number: LM74610-Q1

Hi team,

LM74610-Q1 explain Zero IQ, but what is the real power consumption when it is a normal mode?

Is the total power consumption calcuated as below? Otherwise, can you correct it?

  -. Power consumption in normal mode = I_Gate down(6.8uA) + I_Anode(30uA) + I_Charge current(46uA) ?

  -. Additionally, is I_Charge current is consumed all the time or can it be ignored because of depending on duty ratio? 

Thanks,

Sam Lee

  • Hi Lee,

    Real power is consumed to operate the charge pump (46uA) and current consumed during the turn off/on by the drive circuit.

    Though no current wasted, all the current is part of load current.

    Let me get back on this question in more detail in couple of days.

    Let me know if you require a faster response.

    Regards,

    Kari.

  • Hi Kari,

    Thank you for your reply. Yes, I'd like to get faster response for a customer. They're currently reviewing how much power is used for the selection of this device.

    Best Regards,

    Sam Lee

  • Hi Kari,

    Could you please provide more info?

         Iq = 46mA (charge pump) + current consumed during the turn off/on by the drive circuit

    I don't know how much is the current consumed during the turn off/on by the drive circuit. Can you explain it?

     

    Thanks,

    Sam Lee

  • Hi Kari,

    My customer is facing similar problems. Since quiescent current is a crucial design consideration for their system, they want to know how to calculate real Iq and  power consumption for LM74610. Would you please share more comments on this question?

    Also, during T1 when there is nearly no voltage drop on anode and cathode, is LM74610 powered by charge pump capacitor? 

    Thanks and best regards,

    Charles

  • Hello Jingyan

    Operating Iq current is calculated based on charge pump ON current

     

    With 2.2uF charge pump capacitor, charge pump ON time is 55ms and OFF time is 2.66 seconds.

    Current taken from the input(battery) is average of current during ON time and OFF time.

     

    During ON time charge pump consumes 46uA and 0uA during OFF (Though 0.95 uA is taken back from Charge pump capacitor VCAP, but that does not count in Iq).

     

    Average Iq current is dQ/dt = ( 46uA * 55ms + 0uA *2.66s) / (55ms +2.66s) = 0.932uA and this current is taken out of battery to keep the part functioning all the time.

    This is nominal current and based on 2.2uF VCAP capacitor.

    Regards,
    Kari.

  • Hi Kari,

    This solves my problem perfectly. Thanks so much!

    Best regards,

    Charles

  • Hi

    If your question is answered, click "this resolved my issue" button at the end.

    Regards,

    Kari.