Charger 16 Click Board™

Product Code: MIKROE-4768

How Does The Charger 16 Click Board™ Work? The Charger 16 Click Board™ as its foundation uses the LT1571, a current-mode PWM step-down (buck) charger from Analog Devices. This battery charger represents a simple, efficient solution to fast-charge rechargeable batteries, including lithium-ion (Li-Ion), nickel-metal-hydride (NiMH), and nickel-cadmium (NiCd) using constant-current and/or constant-voltage control. The internal switch is capable of delivering a 1.5A DC (2A peak current). A saturating switch operates at 500kHz, which provides high efficiency and a small charger size. The Charger 16 Click Board™ communicates with MCU using two GPIO pins. The Enable pin, labeled as EN and routed to the CS pin of the mikroBUS™ socket, optimizes power consumption and is used for power ON/OFF purposes (driver operation permission). The onboard current sense resistor (R7) allows simple charge current programming to within 5% accuracy. Charge current can be programmed with the PWM from the mikroBUS™ socket by pulse width modulating current on a PROG pin with a switch Q2 to R7 at a frequency higher than a few kHz.

Charge current will be proportional to the duty cycle of Q2 with full-current at 100% duty cycle. This Click board™ also comes with an indication, red LED labeled as CHARGE, for battery near full-charge state, when the charge current drops to 20% of the programmed value, and selectable constant voltage for 4.1V or 4.2V per cell with 0.6% accuracy. Selection can be performed by onboard SMD jumper labeled as CELL SEL. Besides, the charge termination-flag threshold can be reduced from the default 20% level to as low as 7.5% of the programmed full charge current by positioning an onboard R5 resistor of appropriate value. The Charger 16 Click Board™ supports an external power supply for the LT1571, which can be connected to the input terminal labeled as VIN and should be within the range of 8V to 20V. When the input voltage is removed, its supply voltage pin drops to 0.7V below the battery voltage forcing the charger into a low-battery drain (5mA typical) Sleep mode. This Click board™ operates only with a 5V logic voltage level. The board must perform appropriate logic voltage level conversion before use with MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development. Specifications Type Battery charger Applications Can be used as a Li-Ion, NiMH, NiCd battery charger for portable devices and accessories, power tools, and more On-board modules LT1571 - constant-current/constant-voltage battery charger with preset voltage and termination flag from Analog Devices Key Features Low power consumption, low shutdown current, fast charging of Li-Ion, NiMH and NiCd batteries, simple charge current programming, high efficency up to 1.5A charge current, battery voltage selection, battery charging indication, and more Interface GPIO,PWM Compatibility mikroBUS Click board size M (42.9 x 25.4 mm) Input Voltage 5V,External Pinout diagram This table shows how the pinout on Charger 16 Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns). Notes Pin Pin Notes NC 1 AN PWM 16 PWM PWM Signal NC 2 RST INT 15 NC Enable EN 3 CS RX 14 NC NC 4 SCK TX 13 NC NC 5 MISO SCL 12 NC NC 6 MOSI SDA 11 NC NC 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 LD2 CHARGE - C