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TPS564208 - Current consumption

Loic Jacquinot
Prodigy 230 points
Other Parts Discussed in Thread: TPS564208, TPS62745

Hi,

For an handheld system I use a TPS564208 to get 3.3V from a 7.4V Li-Po battery. To test it I used a laboratory power supply. Actually on my PCB I have only the TPS564208 and its necessary capacitors, resistors and 2.2uH inductor.

Problem (or not?), even with no load, it consumes about 25mA... As it is will be used as a permanent supply for the system (low power MCU), it will be a big problem for battery lifetime...

To get 3.3V I set the reference resistors to 33.2k and 10k.

I tried to change 33.2k to 332k and 10k to 100k but the cunsumption was worse, about 70mA...

I used this one because I thought it would be better than an LDO to go down to 3.3V with a 7.4V supply.

Do you know if it's a normal case or if I did something wrong? Is there a better device to do it?

On this rail I need only 20mA (Low power MCU + 1 LED)

I also have two other rails which can be enabled or disabled by the low power MCU (3.3V 250mA and 5V 1.5A)

Thank you.

Regards,

Loic

  • 0
    TI__Guru**** 191445 points
    I would expect the no load input current to be in the range of about 20 mA, so I think your measurement may be pretty close. TPS564208 does not have any special light load efficiency features. It is optimized for higher output current up to 4 A. I would recommend you take a look at TPS62745 for your application. It has > 80 % efficiency above about 9 uA load current and near 90% efficiency at 20 mA load current. Let me know what you think.