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LM74700-Q1: OUTPUT DROP

Zoe Ko
Expert 3820 points
Part Number: LM74700-Q1
Other Parts Discussed in Thread: LM74610-Q1,

Hi team,

The LM74610-Q1 designed the charge pump on/off for saving power and cause output voltage drop.

Does the LM74700-Q1 also the same with output voltage drop?

Thank you!

  • 0
    TI__Guru** 105361 points

    Hi Zoe,

    LM74700-Q1 charge pump architecture is different. The output voltage does not drop in the case of LM74700-Q1.

    Can you please share the application use case details and EE

    Best Regards, Rakesh

  • 0
    TI__Guru 57737 points

    Hi Zoe Ko,

    Charge pump operates by taking power from Vanode.
    For example, charge pump delivers 300uA to VCAP current at Vanode 12V, but to deliver 300uA it takes 1.4mA current (short time) from Vanode.

    Charge pump is turned ON/OFF to reduce the average Iq current, at VCAP-Vanode reaches 13V, charge pump is turned off, then due to leakage VCAP-Vanode discharges and when it reaches 12.1V, charge pump is turned on (13V and 12.1 V are specified in datasheet page 6). Iq current will see a pulsed behavior when charge pump turns ON/OFF. Average Iq current is mentioned in the datasheet. When the charge pump is ON, it takes 1.4mA (typical) from Anode. Actual current into VCAP is 300uA. Ratio of 1.4mA/300uA = 4.67. So 4.67x current is taken from Vanode due to charge pump.

  • 0 in reply to Praveen GD
    TI__Guru** 105361 points

    Hi Zoe,

    Can you share us the application use case details and EE

    Best Regards, Rakesh