- TI INA301EVM - "High accuracy, high slew-rate current sense amplifier with integrated high-speed comparator optimized for overcurrent protection."
I saw this board and thought it was pretty useful... see why below...
Need your SBC to sense current somewhere in a DC circuit, what’s the best way to do it? Yes, you attempt to make a circuit to do so… or you can just save the time and buy one. I’m a big advocate of “not building a project before building a project.” You want your SBC or MCU to sense current for some reason, not spend any amount of time creating and troubleshooting a way.
I saw this board from TI and thought it would make a good addition to one’s dev board cache. Very few kits I’ve come across has any way of sensing current.
The TI INA301EVM (an evaluation board) is a current sensing device that amplifies the voltage measurement across a chosen shunt resistor in line with the current source. This analog output device amplifies the signal so that it is suitable for a microcontroller to read its input to an ADC. The INA301 (series) can operate on a supply voltage from 2.7V to 5.5V while operating up to 36V on its input.
When measuring current from a device or wire/trace, the voltage is read across a shunt resistor from 0V to 36V range. The output has 2 settable modes, via the reset pin hooked up to one of the GPIO pins of the microcontroller, set high or low.
The first mode is transparent mode, which the analog out follows the analog in signal, which is intended to be connected to the ADC pin. The other mode is latched mode. Where an alert can be set using the value of the Rlimit resistor, when an overcurrent is detected, the ALERT pin is pulled low for the microcontroller to detect on its GPIO pin. To determine your Rlimit resistor value, You choose the voltage threshold for the voltage to trip at, using Vlimit in the following equation:
Threshold limit-setting resistor value, RLIMIT = VLIMIT / ILIMIT
- 4 V / 80 µA = 50 kΩ
Features:
The device has an excellent temperature range from: -40 C to 125 C
Low supply current consumption: at 700uA
The elavuation board has 3 different differential amplifiers. 20, 50, 100-V/V gain. Why do you need this? In case the resulting voltage measurement off the current sense resistor is too low to read for the system.
Application and use:
Battery Monitor
This device can be used as Battery Monitor where a microcontroller is using the analog output of the INA301 to measure battery current consumption overtime.
Power Supply
Current monitor with alarm, the microcontroller can monitor the alarm pin of the INA301 and go into shutdown or sleep when current consumption is too high. This alarm function can also be used as a signal to turn other devices on and off based on the set current alarm.
To get a board, see here. To read even more about it, visit here.
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