Improve your AC measurement with MCP3201 and MK64FN1M0VDC12

AC Current Click is based on the MCP607, a micropower CMOS operational amplifier from Microchip. The non-invasive sensor that should be used along this Click board™ works by utilizing the electromagnetic induction phenomenon, similar to a transformer. The primary coil does not exist, though; the electromagnetic field is generated by the AC Current running through the cable, which is measured. The core of the sensing probe is split, allowing it to clamp on the current conducting cable. Since the sensor does not influence the measurement circuitry in any way while being galvanically isolated simultaneously, it is an ideal solution to measure current running through mains or similar high-voltage installations. Note that only the AC current can be measured since the DC current cannot generate the alternating magnetic field, so the sensor can only be used for the AC current measurement. The Click board™ comes equipped with the 3.5mm jack connector, which is used to attach the sensing probe. The sensor input is filtered and amplified over the MCP607 so that the readings can stay reliable and protected against EMI and radio interference. The reference voltage for the conversion is 2.048V, and the MAX6106, a voltage reference from Analog Devices

provides it. It samples the input voltage generated by the contactless, non-invasive current sensor attached to the 3.5mm jack connector. This allows a minimal distortion of the input. The amplification ratio (G) is calculated using the non-inverting operational amplifier configuration formula: G = 1 + R4 / R3. Knowing the maximum voltage of the sensor (for 10A current), the reference voltage of 2.048V for the ADC, and the gain factor of the op-amp, it is easy to calculate the value for the measured current. The Click board™ comes with library functions that do all the necessary calculations, providing a simple and quick solution for application development. A user can also easily develop his methods and functions using existing ones if some other sensor with different nominal values is used. However, this Click board™ also comes as part of the AC Current click - bundle, which also contains the current measuring sensor calibrated and well suited to work with the AC Current click (10A - 1V). AC Current Click uses a standard 3-Wire (read-only) SPI serial interface of the MCP3201 to communicate with the host MCU. Besides the onboard A/D converter, an analog signal path is available to the users, allowing the board™ to fit into various usage scenarios. Besides

the onboard ADC, it is possible to use an external converter by using the AN pin of the mikroBUS™. The preconditioned voltage from the first (non-inverting) operational amplifier is routed to the onboard ADC and another op-amp, which acts as the buffer with unity gain. It provides a buffered analog voltage at the AN pin, which can be used externally, bypassing the onboard ADC. The MCP607 consists of two integrated op-amps, so the same IC is used both for the input preconditioning and the output buffer. Note that although the Click board™ is meant to measure current without making contact using a galvanically isolated sensor over an isolated cable, special care should always be taken when working with dangerous voltages. Any operation which involves high voltage should be performed by trained personnel. This Click board™ can operate with either 3.3V or 5V logic levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Also, this 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.

Clicker 2 for Kinetis is a compact starter development board that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It comes with an onboard 32-bit ARM Cortex-M4F microcontroller, the MK64FN1M0VDC12 from NXP Semiconductors, two mikroBUS™ sockets for Click board™ connectivity, a USB connector, LED indicators, buttons, a JTAG programmer connector, and two 26-pin headers for interfacing with external electronics. Its compact design with clear and easily recognizable silkscreen markings allows you to build gadgets with unique functionalities and

features quickly. Each part of the Clicker 2 for Kinetis development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the Clicker 2 for Kinetis programming method, using a USB HID mikroBootloader or an external mikroProg connector for Kinetis programmer, the Clicker 2 board also includes a clean and regulated power supply module for the development kit. It provides two ways of board-powering; through the USB Micro-B cable, where onboard voltage regulators provide the appropriate voltage levels to each component on the board, or

using a Li-Polymer battery via an onboard battery connector. All communication methods that mikroBUS™ itself supports are on this board, including the well-established mikroBUS™ socket, reset button, and several user-configurable buttons and LED indicators. Clicker 2 for Kinetis is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.