TPS61021A: Iq

Kai Hsiao

Guru 12675 points

Part Number: TPS61021A

Hi Sir

I saw datasheet ISD max is 3uA ,but when I use TPS61021A to control EN H to L ,we will measure a 30uA peak current

May I know the reason ?

The peak current is measured from EVM and 150uF is not populated

over 7 years ago

0 Helen chen over 7 years ago

TI__Mastermind 40080 points

3uA means steady state current, not the transient current. the 30uA peak is due to the suddenly discharge current when EN gets L.

0 Kai Hsiao over 7 years ago in reply to Helen chen

Guru 12675 points

HI Helen

Sorry!! update the waveform

You could see Iin will have 34uA peak current after enable from High to Low around 30s

If have this kind of peak current ,it will effect battery life ,could you kindly help to double confirm ?

I can't make sure this issue will happen on TPS61021 or TPS61021A

0 Helen chen over 7 years ago in reply to Kai Hsiao

TI__Mastermind 40080 points

what is the green waveform in channel 4?

0 Kai Hsiao over 7 years ago in reply to Helen chen

Guru 12675 points

Hi Helen

Due to we don't have current probe to measure the small current ,so we use resistor to do

Iin = blue waveform - green waveform

0 Helen chen over 7 years ago in reply to Kai Hsiao

TI__Mastermind 40080 points

Then what is the blue waveform? what is the green waveform ?

0 Kai Hsiao over 7 years ago in reply to Helen chen

Guru 12675 points

Helen

Iin = (Vin1-Vin2)/10kohm

Vin1=Blue waveform

Vin2=Green waveform

0 Helen chen over 7 years ago in reply to Kai Hsiao

TI__Mastermind 40080 points

Thanks.

I think this is a test problem. could you please test again to verify it?

0 Kai Hsiao over 7 years ago in reply to Helen chen

Guru 12675 points

Hi Helen

May I know which test method I can improve ?

0 Helen chen over 7 years ago in reply to Kai Hsiao

TI__Mastermind 40080 points

I'm worried wether the signal is disturbed during the test, could you test it again, make Vin1 and Vin2 refer to the same GND.

0 Kai Hsiao over 7 years ago in reply to Helen chen

Guru 12675 points

Hi Helen

About below figure ,this result test by Tektronix DMM7510 multimeter ,could you help to double confirm again

DMM7510-Datasheet_1KW-60022-2.pdf

0 Helen chen over 7 years ago in reply to Kai Hsiao

TI__Mastermind 40080 points

OK, we'll double confirm it, please wait in patience.

0 Kai Hsiao over 7 years ago in reply to Kai Hsiao

Guru 12675 points

Hi Helen

Have any good news about this question ?

0 Helen chen over 7 years ago in reply to Kai Hsiao

TI__Mastermind 40080 points

will reply you tomorrow

0 Helen chen over 7 years ago in reply to Helen chen

TI__Mastermind 40080 points

you can see the input current spike occurs at when Vo is very low. TPS61021A 's internal logic is supplied by the Vout. When it is disabled and Vo drop to a very low value, around the threshold of the internal logic gate Vt, may generate some leakage some current at this time because of the uncertainty. When Vo is lower than Vt, the leakage will disappear.

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TPS61021A: Iq