LM46001-Q1: Overall current consumption without load for specific configuration

Johnny Lorang

Part Number: LM46001-Q1

Hello,

I have a question regarding the current consumption of the LM46001-Q1 @ no-load.

The datasheet indicates a typical operating quiescent current of 24uA under certain test conditions. In our application, the current consumption in the no load case is critical. However, our setup differs in several points from the specifications in the datasheet. The relevant section of our schematics is shown below:

The input voltage at Vin would be around 12V.

As it can be derived from the schematics, we are planning to have a switching frequency of 2.1MHz and a voltage output of 5V

Thus the values for R_fbt and R_fbb differ from the ones given in the datasheet, as well as the inductance (L102 with 6.8uH).

What would be the overall current consumption of this configuration without any load (i.e. I_out=0A)

What would be the behavior of the converter at very light loads regarding efficiency?

Best regards,

Johnny

over 5 years ago

0 Ambreesh Tripathi over 5 years ago

TI__Expert 6860 points

Johny ,

As you can see in the schematic , the feedback resistor affects the Iq of the design . My recommendatuio here will be to use lower feedback resistor as 249k and calculate the top resistor accordingly .

The device will switch in PFM mode at light load .

---Ambreesh

0 Johnny Lorang over 5 years ago in reply to Ambreesh Tripathi

Prodigy 90 points

Hello Ambreesh,

Thank you for your answer. This is a good point, but we would like to refrain from using resistors with values higher than 100kOhm.

Thus we would still need to know what the overall current consumption of this configuration would be without any load (i.e. I_out=0A).

Best regards,

Johnny

0 Arief Hernadi over 5 years ago in reply to Johnny Lorang

TI__Mastermind 23845 points

Hi,

I think this Iq needs to be tested for a given application. I currently do not have evaluation module in the lab but we can try to send you one if you like.

Thanks

-Arief

0 Johnny Lorang over 5 years ago in reply to Arief Hernadi

Prodigy 90 points

Hi Arief,

Thank you for your answer.

In the meantime, we have done the corresponding measurements on an evaluation module.

Best regards,

Johnny

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LM46001-Q1: Overall current consumption without load for specific configuration