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[TPS54260]Average current at ultra-low load current

Tomoaki Yoshida
Expert 2200 points
Other Parts Discussed in Thread: LM43602, TPS54260, LM46002

Hi

I would like to know average quiescent current at ultra-low load current.

I'm considering 12V/2A output system, and input voltage is 24V.

However, almost, IC that becomes the load is in a sleep state, it will sometimes cause.

At waking time, the load current is 100mA, when sleep is 1mA.

During the waking time, the pulse of the load current 2A occurs.

Pulse width is about 500us from 100us.

I would like to know average quiescent current.

Since the ratio of the time that is happening and the sleep time required to consider,

the average current is averaging the quiscent currents in each load current by duty ratio.

In the case 1mA or 100mA,  I think that it will be operating in pulse skip mode, how much current consumption.

I used Webench, consider as shown in the following figure 12V, the circuit configuration of a 2A output.

Is there a way to know 1mA, the average current consumption during 100mA in this circuit?

If the efficiency of the results of at 100mA, but I think that it is calculated back to be able to calculate the average current,
in Webench, it does not come out only up to 200mA efficiency of simulation results.

Please let me know if there is a way to know the average current.

In this case, sometimes 2A of pulse current is generated.

How it would be considered fever?

I believe if the pulse width is short, the heat is not completely raised, and therfore I want to know the formula,

such as showing a relationship between heat and pulse width.

Thanks.

  • 0
    TI__Guru**** 191445 points
    Usually I just estimate it as follows. Iin (avg) = (Vout * Iout) / (Vin * Eff). You can use the efficiency graphs from webench.
  • 0 in reply to JohnTucker
    Expert 2200 points

    Hi John

    Thank you for your reply.
    It's all well and good if it is how it was taught to you, but in webench, the minimum load current can not only set up to 200mA.
    I will not be able to know the efficiency at load current such as 100mA and 1mA.

    I think also LM46002 and LM43602 be the target in addition to the TPS54260.
    LM46002 and LM43602 will be able to know the efficiency webench if 100mA, but because 1mA of load current is a too low power consumption, I think that it is difficult in tools such as webench.
    Would not the technique, such as can be theoretically calculated?

    Thanks

    Tomoaki Yoshida

    For some reason I cannot reply so I am editing here...You can change the operating point in the Op Vals section of webench.  You can set the output current to 100 mA or whatever and read the input current directly.