TPS61021A: Consumption with light load

manoel dahan

Part Number: TPS61021A
Other Parts Discussed in Thread: TPS61094, TPS61299EVM-016, TPS61299, TPS61299EVM-103

Hi,

We designed a product that uses the TPS61021A to power a modem.
Recently we tested the PSM (Power Saving Mode) of the modem that requires the modem to be powered with a current as low as 4µA.
We measured the current actually drawn, and we observed a 100µA average with picks of around 100mA.

I saw that the chart is not showing below 100µA (our Vout is 3V3 and Vin between 3V and 2V):

I saw a similar problem here:
TPS61021A: Pulsed Currents on Demo Board - Power management forum - Power management - TI E2E support forums

Is it still expected to have this behaviour like said in the link above or is it not a normal behaviour.
if it is an expected behaviour, is there a way to reduce the consumption with a light load ?
if it is not possible to reduce greatly this consumption, could you recommend a better component that can handle high currents during a network connection (up to 1,5A) and low currents during PSM ?

Thank you beforehand,

4 months ago

0 Travis Wang 4 months ago

TI__Expert 4115 points

Hi Dahan,

If the current is measured from the input, then it's a normal behavior. If you need low current consumption in 4uA load, we recommend TPS612997 or TPS61094. These devices supports high efficiency at 1uA load. But its current capability only supports 1A output when Vin is 2V and 1.5A output when Vin is 3V. High efficiency under 4uA load is very hard to be achieved and we do not have such devices with bigger current capability.

Best Regards,

Travis

0 manoel dahan 4 months ago in reply to Travis Wang

Prodigy 20 points

Hi Wang,

Thank you for your answer.
Because our input voltage is between 2V~3,3V, the peak (140µs to 2ms) drawn current measured from the input varies from 1A @3V to 1,5A @2,4V but the maximum current drawn by the modem is theoretically of only 800mA (with an average of 100mA). I don't think that the TPS61094 could handle such current but maybe the TPS612997.
is the TPS61299EVM-016 the right board ?

0 Travis Wang 4 months ago in reply to manoel dahan

TI__Expert 4115 points

Hi Dahan,

No, If you need TPS612997, you need to apply for TPS61299EVM-103 and TPS612997 samples. The default IC on TPS61299EVM-103 is the 1.2A current version TPS61299 so you need to apply for TPS612997 samples and replace the IC.

Best Regards,

Travis

0 manoel dahan 4 months ago in reply to Travis Wang

Prodigy 20 points

Hi Travis,

I bought the EVB but I'm not able to replace the IC (too small)
I tested it as is with a 3V input 1,4A OCP. My modem doesn't start, the output voltage is steady at 3.3V but the current measurement at the output of the TPS61299 is showing a continuous pattern as shown below :

What could cause the output current to have this waveform ?

+1 Travis Wang 4 months ago in reply to manoel dahan

TI__Expert 4115 points

Hi Manoel,

The output current depends on your load. I don't know what your modem is but it's sinking current like your pattern.

Re-assigning this thread to the expert of TPS61299.

Best Regards,

Travis

0 manoel dahan 3 months ago in reply to Travis Wang

Prodigy 20 points

Hi Travis,

Just for info, the TPS61299 actually fit our needs because we finally need only 1A output.
And the current consumption with light load is really good.
Thanks for your help.
best regards,
Manoel