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INA253: How to select right current sensor for load current measurement

Part Number: INA253
Other Parts Discussed in Thread: BQ25895, TPS61088, , INA260

Hello TI, 

              we want measure the Output current(Load Current) of TPS61088 to adjust BQ25895 battery charging current, there is any suggestion how to figure out this ...?


We found INA253 current sense amplifier, it is suitable to my application or any other alternatives ..?

1.Need to measure the Output current(Load current consumption) of TPS61088

2.TPS61088 output rating is 5V/5A, current sensor able to handle the voltage and current 

3.Current sensor output is provided to Host controller of the system 

Try to suggest any alternative of DC current sensor to the system as per above mention points, thanks for your valuable support

Thanks and Regards,

Rahul Surawase 

  • Hi Rahul,

    I apologize for the length of response, but there's quite a bit to unravel here, and I want to make sure we get you on the straight and narrow.

    First, I'm having a bit of trouble envisioning your system layout here. The BQ25895 has a built in 7-bit ADC for the purposes of monitoring charge current and prevent overloads on the input side, and can take action based on that measurement (check out section 8.2.6.2 of the BQ25895 DS for more info). Is there a reason you're wanting to measure current on the load side beyond the Bboost converter rather than with this? Are you operating a load in parallel with the battery charger or something that is making you want to throttle back the charge current in certain situations? Something like below (VBUS not shown)?

    Regarding your three points on INA253, I have some follow up thoughts/questions here:

    1. Measuring the output current here shouldn't be incredibly difficult if you want to go this route, but we need to make some engineering decisions in regards to the current we are measuring, which will affect both your choice in shunt as well as device. 

    2. Are you saying that your TPS61088 is designed to 5v@5A, i.e., 25W? Is this the maximum current to be seen in the system, or the nominal? Ultimately, we need to choose a shunt and gain variant that will allow us to utilize an optimal portion of the dynamic range of the device. For example, with the INA253, this device has an integrated 2mohm shunt, and if we use the A3 version of the device, a 5A measurement in theory would correlate to a 2V output on the device (5A*400mv/A = 2V). This would be utilizing about 40% of the device's dynamic range, and would provide a range of 0V-2V corresponding to 0A-5A. This is obviously based on calculations, and you'll need to take signal error into account here, which may lead you to want to choose a configuration where you utilise more of the range of the part. We have a great video series that can help you with error calculation located here

    3. You can accomplish this one of two ways: first, you can use an analog part such as the INA253, and feed this into an ADC pin of your microcontroller, or, you can use a digital out part, such as the INA260, which will digitally quantify the measurement internally, and you can then use I2C to pass the information to the MCU.

    Also, although this isn't a solar application, you might want to have a look at TIDA-01556, as this reference design provides some great insight into the capabilities of the BQ25895's dynamic power management (DPM), and may give you some additional information here.