HOW DOES IT WORK?

Hall Current 12 Click as its foundation uses the TMCS1100A4, a precision Hall-effect current sensor, featuring a 600V isolation working voltage, <1% full-scale error across temperature, and a reference voltage enabling unidirectional or bidirectional current sensing from Texas Instruments. The input current flows through an internal 1.8mΩ conductor that generates a magnetic field measured by an integrated Hall-effect sensor and amplified by a precision signal chain. The device has a bandwidth of 80kHz and can be used for both AC and DC current measurements. It is optimized for high accuracy and temperature stability, with offset and sensitivity compensated across the operating temperature range.

The reference voltage provided to the TMCS1100A4 on the VREF pin determines the zero current output voltage. This zero-current output level, along with sensitivity, determines the measurable input current range allowing for unidirectional or bidirectional sensing. An onboard SMD switch labeled as VREF SEL, placed to an appropriate position marked as VCC/2 and GND, can select reference voltage. With VCC/2, the TMCS1100A4 measures input current up to ±5.75A, while with the GND position from 0.125A up to 12A.

Hall Current 12 Click has two ways to communicate with the MCU. The output analog signal from TMCS1100A4 is forwarded to the input of the operational amplifier, the LMV321 low-voltage rail-to-rail OpAmp from Texas Instruments, which represents the most cost-effective solution for applications where low voltage operation is needed. The output of the LMV321 OPAmp has a stable unity-gain, acting as a buffer so that the host MCU can sample the output voltage of the TMCS1100A4 via the AN pin of the mikroBUS™ socket. Also, with this method, it is possible to increase the sensitivity of its output signal by placing the switch labeled as SENSITIVITY to the appropriate position marked as LOW or HIGH, giving the user the option to select reduced or increased sensitivity.

Another way of signal processing is for the TMCS1100A4 analog output signal to be converted to a digital value using MCP3221, a successive approximation A/D converter with a 12-bit resolution from Microchip using a 2-wire I2C compatible interface. Selection can be performed by onboard SMD switch labeled as VOUT SEL, placing it to an appropriate position marked as AN and ADC. With the MCP3221, data transfers at rates of up to 100kbit/s in the Standard and up to 400kbit/s in the Fast Mode.

Also, this Click board™ should be connected in series with the load. The current is measured by two onboard terminal connectors, one terminal block for the positive and the other for the negative current input.

This Click board™ can operate with both 3.3V and 5V logic voltage levels selected via the VCC SEL jumper. This way, it is allowed for both 3.3V and 5V capable MCUs to use the communication lines properly. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development.