Charger 11 Click is a LiFePO4 (lithium iron phosphate) battery charger. This Click can be used for Low-Cost LiFePO4 battery chargers, or Power Tools, toys, backup energy storage solutions, etc. Charger 11 is based on MCP73123T controller which has some extra features enabling charging without too much hassle. This Click board™ has charging current control which uses SPI interface through MCP4161 IC, which is an 8-bit digital potentiometer. For battery voltage monitoring this Click board™ uses MCP3221A5T analog to digital converter through I2C interface. On the board, there is a Power LED and two extra LED’s which can be used for charging indications.

Charger 11 Click is supported by a mikroSDK compliant library, which includes functions that simplify software development.

As a Lithium Iron Phosphate battery requires a very accurate current and voltage for charging, Charger 11 Click can be a perfect solution for such a task. Charger 11 Click is equipped with a highly integrated LiFePO4 battery charger. This Click has a charging current control IC over SPI interface which ensures perfect and efficient charging. With Analog-To-Digital Converter through its 12-bit resolution and I2C interface, Charger 11 Click has precise battery voltage monitoring. Charger 11 click meets all requirements for charging this higher specific capacity, but low-density batteries.

Charger 11 Click is based on the MCP73123 - a highly integrated Lithium Iron Phosphate (LiFePO4) battery charge management controller for use in space-limited and cost-sensitive applications, from Microchip. MCP73123 is an efficient Lithium Iron Phosphate battery charger, thanks to specific charge algorithms for LiFePO4 batteries to achieve optimal capacity and safety in shortest charging time possible. Along with its small physical size, the low number of external components makes this IC ideally suitable for various applications. MCP73123 is designed to employ a constant current and constant voltage charge algorithm. The 3.6V factory preset reference voltage simplifies design. The fast charge constant current is set by a digital potentiometer, on this Click it is MCP4161 with external 1K resistor in series. The MCP73123 also limits the charge current based on the temperature during high power or high ambient conditions. This thermal regulation optimizes the charge cycle time while maintaining device reliability. PROG pin of the MCP73123 also serves as the enable pin, where on this Click it is wired in rheostat configuration with the digital potentiometer. That way the charging current can be controlled.

The digital potentiometer on Charger 11 Click is MCP4161 which offers a wide range of product offerings using a SPI interface. WiperLock technology allows application-specific calibration settings to be secured in EEPROM. This digital pot is tied with charger IC over its P0A control pin. By assigning values on MCP4161 from 0 to 10 kiloohms battery charging can be controlled. As there is a 1 K resistor in series it can never be 0 ohms on MCP73123 chargers PROG pin. However, maximum resistance cannot exceed 11 kiloohms. Fast charging can be regulated with 10K on PROG pin to get 130 mA. To get 1000 mA digital potentiometer needs to go down to 0,1 K, along with external resistor, which makes 1,1 K. Communication with digital potentiometer on this Click and that way controlling the charger is done through SPI interface.

Another feature of Charger 11 Click is a battery voltage monitoring which is done by using a MCP3221A5T Analog-To-Digital converter. It is a 12-bit resolution SOT12 package device which provides one single ended input and is based on advanced CMOS technology. Communication to the MCP3221A5T is done by I2C interface where standard and fast modes are available for this device.

Charger 11 Click for voltage reference use a MCP1541, which has a high precision output voltage of 4.096 volts, and which is then compared to battery voltage in order to get precise measurements. This voltage reference circuit uses a combination of an advanced CMOS design and EPROM timing to provide initial tolerance of ±1% max.

On the right side of the Click board™ is an input screw terminal with corresponding markings, where the recommended external voltage of 6V can be applied. The left screw terminal is reserved for a Lithium Iron Phosphate battery with GND and VBAT+ markings. When connected to power source, the green PWR LED will indicate it. Red LED1 and green LED2 can be used for visual charge monitoring. As those two LEDs are multipurpose, they can be used for various things.

• Interface: GPIO, I²C, SPI
• Compatibility: mikroBUS™
• Dimensions: 42.9 x 25.4mm
• Input Voltage: 3.3V, 5V

• Schematic
• MCP4161 Datasheet
• MCP73123 Datasheet
• mikroSDK
• GitHub