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LM73606-Q1: IQ spec and light load mode efficiency?

user1291824
Prodigy 80 points
Part Number: LM73606-Q1

1. Can you offer the efficiency curve when output current below 1mA ?（12V in/5V out）

2. On the datasheet we find the Iq current is typical 15uA, @25C, can you offer the typical case of corner value?

3. How to calculate efficiency when output current is 50~100uA, should we add the Iq current?

  • 0
    TI__Mastermind 40040 points

    Hello,

    Suggest using WEBENCH which provides efficiency curves for the load ranges in question.  See link below and WeBench is found in the link below.  There in, enter you input, output voltage and load current.

    http://www.ti.com/product/LM73606

    Unfortunately we do not specify corner cases for IQ, only typical [15uA].

  • 0
    TI__Expert 3835 points

    Hi User,

    1. We currently do not have this data, but can offer to you given some time. Will this be in auto mode? At what switching frequency? Is there a reason why you need this low output current for a 6A device?

    2. Iq switching consist of the operating Iq from Vin (Iq_non-sw), leakage current in the EN pin (I_EN), and current from from the bias pin and resistor dividers (I_FB + I_DIV) (this values needs to multiplied by the duty cycle of the switching divided by the efficiency of the device:

    Iq_sw= Iq_non-sw + I_EN + (I_B + I_FB) x (Vout/ (neff x Vin)

     A corner case could be found at the maximum value on the EC table. This is only a rough estimate since cannot provide min/max values.

    3. In low output current is where Iq current matters the most since it will be the factor for lower efficiency in low load situations.

    Thanks,

    Ethan

  • 0 in reply to Ethan T
    Prodigy 80 points

    1. We currently do not have this data, but can offer to you given some time. Will this be in auto mode? At what switching frequency? Is there a reason why you need this low output current for a 6A device?

    -> Expect the data. We need the more high efficiency for Low power requirement ,maybe auto mode is the best choice. The low output current is the case when in low power mode.

    2. I find the EC table for 12uA maximum value, but it is the non-switch mode, if the output current is about 100uA, I think we should get the value from the system characteristics table typical value 15uA, Can we get the max value ? Or can you help to calculate the Iq_sw? 

  • 0 in reply to user1291824
    TI__Expert 3835 points

    Hi User,

    Can you specify what switching frequency you plan to use your application with. I cannot provide a maximum value and can only provide a typical calculation base on efficiency taken from the test at room temperature.

    Regards,

    Ethan