Go Down

Topic: Question about Quiescent Current (Read 288 times) previous topic - next topic

Vitesze

I have a small Cellular controller board that is hooked up to a JSN-SR04T ultrasonic sensor. The board only provides 3.3V, so I have a DC Step-up in between, converting it to 5V.

For my project, power efficiency is extremely important. The device is in Sleep mode most of the time, and the current draw it's at now lies around 200uA. When I looked at the JSN-SR04Ts datasheet though, it mentions a Quiescent current of a whoppin' 5mA, about 25 times higher than what my device consumes right now.

Considering I only need to take measurements with my JSN-SR04T for about 10 seconds per day (combined), is there a way to cut off the JSN-SR04T from my device once it's sleeping, so it doesn't draw that amount of current?

aarg

Use a transistor to switch off the power supply to it when it's not in use.
  ... with a transistor and a large sum of money to spend ...
Please don't PM me with technical questions. Post them in the forum.

Southpark

#2
Dec 07, 2017, 01:19 am Last Edit: Dec 07, 2017, 01:29 am by Southpark
I have a small Cellular controller board that is hooked up to a JSN-SR04T ultrasonic sensor. The board only provides 3.3V, so I have a DC Step-up in between, converting it to 5V.

For my project, power efficiency is extremely important. The device is in Sleep mode most of the time, and the current draw it's at now lies around 200uA. When I looked at the JSN-SR04Ts datasheet though, it mentions a Quiescent current of a whoppin' 5mA, about 25 times higher than what my device consumes right now.

Considering I only need to take measurements with my JSN-SR04T for about 10 seconds per day (combined), is there a way to cut off the JSN-SR04T from my device once it's sleeping, so it doesn't draw that amount of current?
I think you should make things clear about what 'device' you're talking about. When you mention 'device', are you talking about the controller board, or the sensor? Or both?

If you say the device is in 'sleep mode', and it is drawing 200 microamp in sleep mode, then that is sleep mode. So it's like doing what you need (in sleep mode), right?

If the sensor is currently always powered up, then the controller board should perform some kind of extra function to route power to the sensor when the controller board wakes up from sleep mode. And then remove power from the sensor before going to sleep again.

Vitesze

I think you should make things clear about what 'device' you're talking about. When you mention 'device', are you talking about the controller board, or the sensor? Or both?

If you say the device is in 'sleep mode', and it is drawing 200 microamp in sleep mode, then that is sleep mode. So it's like doing what you need (in sleep mode), right?

If the sensor is currently always powered up, then the controller board should perform some kind of extra function to route power to the sensor when the controller board wakes up from sleep mode. And then remove power from the sensor before going to sleep again.
Sorry, when I mention ''device'', I mean the controller + other sensors (basically the whole package). That combined currently uses 200uA. The JSN-SR04T would only be used for a couple of seconds at a time, with 6-hour intervals.

The ''device'' will be permanently powered up with a battery. So from the look of your and the other person's reply, I should be able to cut off power to this before sleeping, and boot it up again once the ''device'' wakes up...Thanks!

Southpark

The ''device'' will be permanently powered up with a battery. So from the look of your and the other person's reply, I should be able to cut off power to this before sleeping, and boot it up again once the ''device'' wakes up...Thanks!
Yep! Should be good. Just make sure that adequate time is provided for the sensor to get started up before taking any readings etc.

MarkT

Make sure the boost converter you choose has an enable pin...
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

Go Up