LIS3DH current consumption

[bojan]

Posted on January 16, 2017 at 13:36

Hello guys,

I'm using LIS3DH accelerometer in my current design. I need it to detect the movement.

ODR is set to be 10Hz. According to

http://www.st.com/content/ccc/resource/technical/document/application_note/77/ed/e7/e1/28/5a/45/d6/CD00290pdf/files/CD00290pdf/jcr:content/translations/en.CD00290pdf

document (page 10), LIS3DH should consume about 4uA of the current in both Normal and Low power modes.

However, when I measure the current consumption, I get the value of about 78uA (@2.5V power supply). When I remove the accelerometer from the power rails and measure the current consumption of mcu in a sleep mode, I get the value of 3.2uA. This clearly implies that about 75uA of the current is consumed by the accelerometer.

The important thing to mention here is that I was supplying the mcu and accelerometer with 3.7V to 4.2V for some time. This is above the recommended supply range for LIS3DH (3.6V maximum). So, is it possible that this over-voltage permanently increased the current consumption? I have the desired functionality even when I supply the system with 3.7V to 4.2V.

Thank you very much for your time and effort.

Sincerely,

Bojan.

#lis3dh Note: this post was migrated and contained many threaded conversations, some content may be missing.

[bojan]

Posted on January 17, 2017 at 16:04

Hey Miroslav,

Just to let you know that disabling pull-up resistor does the magic !

Current consumption is now as expected !

Thank you very much for your assistance, really appreciate it!

Sincerely,

Bojan.

[Giraffy Fi]

Posted on March 31, 2017 at 08:03

Hey Miroslav,

Is there an equivalent 'REG_CTRL0' for LIS3DE?  I am also in the process of hunting down an extra 160uA static current between the MCU and LIS3DE with 4 SPI and 2 Interrupts pin connected.

I tried the trick above for the LIS3DH, by reading and writing address 0x1E.  The responses I got from the register does match the (LIS3D'H') datasheet.  I got 0xA0 @ 0x1E.  Drove SCLK and MOSI high or low did not change the current reading.  

Any advice would be greatly appreciated.

[Miroslav BATEK]

Posted on April 04, 2017 at 18:14

I'm double checking your question with sensor specialists, but I assume if there is internal pull-up on SDA/SA pin then it is automatically disconnected if you use SPI bus, because the pin is driven by push/pull output (MISO signal).

[Giraffy Fi]

Posted on April 04, 2017 at 22:14

Hello Miroslav,

Thanks for checking in.  So from the MCU side, adding a pullup on the IO to the SA0 (MISO) pin saved ~150uA, note that before it was high impedance (no pull), I guess the SA0 needs a little help.  I could use LIS3DH or E interchangeably, the LIS3DE happen to be available so we bought a batch for a project build.  Would be nice if you can confirm the 'Reg0' for the LIS3DE, just to give us another knob to turn.  Thanks.  Keep me posted.

FI 

[Giraffy Fi]

Posted on April 04, 2017 at 22:17

Interesting, k'n'o'b (above shown as ****) is censored by the site?  Ha.

[Miroslav BATEK]

Posted on April 10, 2017 at 14:55

Hello Giraffy,

frankly speaking, I don't understand  why 

adding a pull-up on the SA0/MISO pin should save 150uA. There is internal pull-up in the LIS3DE on this pin. Maybe if I would see your schematic it would be more clear.

Anyway, I can confirm that i

t is possible to disconnect this internal pull-up by setting to 1 the bit 7 (MSB) of register at address 1Eh (do not modify the content of the other bits!). Note: this functionality is not guaranteed (and tested) by STMicroelectronics on LIS3DE device. 

The internal pull-up on SDO/SA0 pin is not automatically disconnected when SPI bus is selected by CS pin.

[Tobias N]

Posted on February 22, 2018 at 11:20

Hi!

Very useful information above!

I have about 130 uA@3V3 higher consumption than expected for LIS3DSH. I suppose it is because pin 7, SEL/SDO is connected to GND. Any possibility to turn off internal pull up on this pin? I can not find in datasheet.

Thanks in advance! 

[? ?_3]

Posted on March 15, 2018 at 10:38

Hello Miroslav,

I also have a similar problem.The power consumption of 3.3v is160uA,and register 0 has been configured 0x

Then following is schematic diagram

.

[Miroslav BATEK]

Posted on March 22, 2018 at 13:48

LIS3DSH has internal pull-up on SEL/SDO pin.

It is possible to disconnect this internal pull-up by setting to 1 the bit 7 (MSB) of register at address 3Fh (do not modify the content of the other bits!). Note: this functionality is not guaranteed (and tested) by STMicroelectronics on LIS3DSH device.

[Tobias N]

Posted on March 22, 2018 at 16:51

Thanks Miroslav

Best regards

Tobias