Lowering power consumption

[TGund]

Hi,

I am currently implementing an application using VL53L1X sensor with NRF52. Our applicaiton needs to consume very low current in order to get long battery life. I am reading VL53L1X sensor data every minute. While i am not reading any VL53L1X data, sensor needs to stay in standby state. So, I tried following cases, 

I make XSHUT pin LOW and i get no lower than 0.1mA. Do I need to call a function from API to work XSHUT pin properly? 

I tried to connect one of the NRF52 pins for VL53L1X VDD pin but it didn't work. The reason could be NRF52 cannot give desired current for VL53L1X. So, I connect transistor NRF52 pin and tried again. It was successfull but do you thing that it is applicable? In production stage, there could be problem since there is a extra component for circuit means that more current consumption.

I couldn't find any thing on the API that lowers the power consumption via software. Is there available such a function?

If there is any suggestion about lowering power consumption please let me know.

Regards,

Taha

[John E KVAM]

When you pull down the XSHUT pin you are going to draw power.

How much you draw pulling down the XSHUT depends on the strength of your pull-up.

According to the VL53L1X datasheet you are going to draw 5 or 6 uA in standby mode.

That's pretty low, is it not?

I'd just do a single range and see how much power you are consuming by just leaving the chip sit there waiting for another range command.

It would save you having to re-configure the chip as a side benefit.

And the very first range actually takes longer than subsequent ranges, so you actually gain a little. (But its not much.)

A minute later you could just issue another range command.

And do consider your Timing Budget. The chip draws 20mA while ranging so a 10 or 20ms Timing budget is better than a longer one.

(But longer is more accurate, so it's a tradeoff.)

[TGund]

Hi,

I have decided not use power off and on VL53L1X because of the first ranging is too long to perform and increases the work load on NRF52.

I am using VL53L1X-SATEL board for examine current consumption but i didn't break the board two pieces to get only the VL53L1X sensor. When I do that the current consumption was very low. So, it satisfy our requirement. The problem is solved.

An other topic that i want to ask you about is how sensor accuracy changes with the input voltage?

Since our application contains 2 AAA battery, battery will eventually drop below 2 V. I made a setup with the adjustable power supply for examine accuracy. I get samples every voltage value and i see that appx. 2 cm difference between 3V - 1.8 V. Do you thing that i need to use regulator to stabilize Voltage to for instance 2.8V? is there some down side using sensor with low voltage?

Regards,

Taha

[John E KVAM]

The datasheet is pretty clear that the Operating voltage is 2.6 to 3.5 V. I've not experimented with what happens below that. So you are kind of on your own.

It may be that we set those voltages so we could meet our accuracy numbers. At some low voltage point the VCSEL will not turn on. But I'd put the regulator in if accuracy was important.

[YNase.1]

Hey @John E KVAM​ , I am new to this forum, I've been using the VL53L1X for a while now, and I am facing an issue with the single shot, I looked around for any examples on how to use single shot as I am trying to only read the distance once every 10 minutes, and since my device is battery powered, having the VL53L1X consume low power is a must. Would you be able to help?