LP8758-E0EVM: Inaccurate low current reading

Tony Liu

Part Number: LP8758-E0EVM
Other Parts Discussed in Thread: LP8758

Hi team,

We put a 12ohm resistor with a current meter in series to the Vout0 of the eval board. When we used the GUI (LP8758-xxEVM GUI — SNVC189.ZIP (6093KB)) to program the output voltage, the GUI read back much lower current. We got the same results after changing to different Vouts and even the 2nd eval board. We understand LP8758 has the resolution of current measurement as 20mA. Is this expected at low current scenario?

Programmed output voltage	Ideal current draw	Current reading from the current meter	Current reading from TI GUI
1V	83mA	80mA	0mA
2V	166mA	160mA	60mA

Thank you,

Tony

over 2 years ago

0 Phil Yi40 over 2 years ago

TI__Mastermind 41461 points

Hi Tony,

The device’s load current measurement is good for Iout ≥ 2 A within 10% accuracy; for small load current, its accuracy may be very low.

Thanks!

Phil

0 Tony Liu over 2 years ago in reply to Phil Yi40

Prodigy 21 points

Hi Phil,

Thanks for the quick answer. We saw that and just don't expect 0mA reading with 83mA scenario. We thought it would get at least 20 or 40mA. Wonder if other people have similar experience.

Regards,

Tony

0 Phil Yi40 over 2 years ago in reply to Tony Liu

TI__Mastermind 41461 points

Hi Tony,

Yes; the similar experience has been seen by other users. The load current measurement is for roughly measurement only.

Thanks!

Phil

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LP8758-E0EVM: Inaccurate low current reading