Current 4 Click Board™

Product Code: MIKROE-4755

How Does The Current 4 Click Board™ Work? The Current 4 Click Board™ as its foundation uses the INA250, a current-sense amplifier with a high-precision, low-drift shunt resistor which can deliver highly accurate measurements over a wide temperature range from Texas Instruments. The INA250 measures the voltage developed across the internal current-sensing resistor when current passes through it. The integrated 2mΩ shunt resistor offers 0.1% tolerance and a low drift of 15pmm/°C, enabling the higher performance of the end equipment. This amplifier allows for high-accuracy current measurements at common-mode voltages and offers a maximum error of 0.84% over the temperature range from -40 to +125°C. The Current 4 Click Board™ communicates with MCU using only one pin routed on the AN pin of the mikroBUS™ socket. The output analogue signal from INA250 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 INA250 via the AN pin of the mikroBUS™ socket. The INA250 can be configured to measure both unidirectional and bidirectional currents through the reference voltage level. For unidirectional operation, the reference pin should be tied to the ground. When the current increases, the output signal also increases upwards from this reference voltage (or ground in this case). For bidirectional currents, an external voltage source can be used as the reference voltage, in this case, a low dropout linear regulator AP7331 from Diodes Incorporated to provide the 2.5V reference supply voltage for the INA250. The reference voltage level can be selected by positioning the SMD jumper labelled VREF SEL to an appropriate position choosing between 2.5V provided by AP7331 or GND. The Current 4 Click Board™ can operate with both 3.3V and 5V logic voltage levels selected via the VCC SEL jumper. This way, it allows 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. Specifications Type Measurements Applications Can be used for applications such as test and measurement, load monitoring and power supplies, automotive, and many more On-board modules INA250 - current-sense amplifier with a high-precision, low-drift shunt resistor which can deliver highly accurate measurements over a wide temperature range from Texas Instruments Key Features Low power consumption, a precise integrated shunt resistor, high accuracy, 500mV/A gain, zero-drift, uni/bidirectional current measurements, and more Interface Analog Compatibility mikroBUS Click board size M (42.9 x 25.4 mm) Input Voltage 3.3V or 5V Pinout diagram This table shows how the pinout on Current 4 Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns). Notes Pin Pin Notes Analog Signal AN 1 AN PWM 16 NC NC 2 RST INT 15 NC NC 3 CS RX 14 NC NC 4 SCK TX 13 NC NC 5 MISO SCL 12 NC NC 6 MOSI SDA 11 NC Power Supply 3.3V 7 3.3V 5V 10 5V Power Supply Ground GND 8 GND GND 9 GND Ground Onboard settings and indicators Label Name Default Description LD1 PWR - Power LED Indicator JP1 VCC SEL Left Logic Level Voltage Selection 3V3/5V: Left position 3V3, Right position 5V