Charger 17 Click

How does it work?

Charger 17 Click is based on the RT9471, a 3A single-cell switching battery charger from Richtek. The RT9471 supports USB OTG current and voltage limit regulations. In addition, the charger supports several protection features, such as over-temperature, VBUS over-voltage, battery over-voltage, system over-voltage, system under-voltage, and more. The Charger 17 Click for power input uses a USB C connector and 5V, where in addition, you can use a VBUS/GND header for powering it from another external source as the VBUS RT4971 input has an operating range from 3.9 up to 13.5V. Charger 17 Click uses a properly labeled JST connector for connecting a battery, and one should take note of the battery polarity as the JST battery connector is NOT standardized. In addition to the battery connector, there is an SYS/GND header as a converter output connection point.

The device provides automatic power path selection to the supply system from the USB C connector, the connected battery, or both of them over the VSYS/GND header. There is a shipping mode that allows you to turn the battery off when shipping or in storage, thus extending the battery life. During charge status, the charger monitors the battery's voltage and selects the appropriate mode (battery supply mode to charge battery mode). In USB OtG applications, the RT9471 can achieve up to 92% boost efficiency at 1A with a 3.8V battery and a 5.15V output voltage. The RT9471 charger indicates how good the power source is over the power good PG LED indicator. This status includes applied VBUS when not in Sleep mode, charger thermal values under threshold settings when not in HZ mode, and more. The charging status can be visually monitored over the STAT LED indicator.

The RT9471 supports JEITA protection during charge mode. The charger can measure the battery's temperature over the TEMP/GND header and the additional NTC thermistor. This feature can be selected from the TEMP REF solder jumper, which is set to the internal position by default. In both ways, the temperature window is programmed over the resistor divider. The device will stop charging the battery if the battery's temperature is lower than T1 or higher than T4 values. For more information, please check the attached datasheet.

Charger 17 Click uses a standard 2-Wire I2C interface to communicate with the host MCU, with speeds up to 3.4Mbits. There are some other functionalities for this Click board™, such as charge enable CE pin where you can turn off battery charging when driving this pin LOW. You can also control the BATFET over the QON pin. That includes exiting the shipping mode and system reset. You can select a power source current limit between 0.5A and 2.4A over the PSL pin. The charger can alert poor source detection, VBUS source type detection, and other events over the INT interrupt pin.

This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using 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

Pinout diagram

This table shows how the pinout on Charger 17 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	PSL	Power Source Selection
BATFET Enable Control	QON	2	RST	INT	15	INT	Interrupt
Charge Enable	CE	3	CS	RX	14	NC
	NC	4	SCK	TX	13	NC
	NC	5	MISO	SCL	12	SCL	I2C Clock
	NC	6	MOSI	SDA	11	SDA	I2C Data
Power Supply	3.3V	7	3.3V	5V	10	NC
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

Charger 17 Click electrical specifications

Software Support

We provide a library for the Charger 17 Click as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager (recommended), downloaded from our LibStock™ or found on Mikroe github account.

Library Description

This library contains API for Charger 17 Click driver.

Key functions

• charger17_enable_charging This function enables charging by setting the CE pin to low logic state.

• charger17_set_psel_2400mA This function sets charging current to 2400mA by setting the PSEL pin to low logic state.

• charger17_read_register This function reads data from the selected register by using I2C serial interface.

Example Description

This example demonstrates the use of Charger 17 Click board™ by enabling battery charging and displaying the charging status.

void application_task ( void ) 
 { 
     uint8_t ic_status, status_0; 
     if ( CHARGER17_OK == charger17_read_register ( &charger17, CHARGER17_REG_IC_STATUS, &ic_status ) ) 
     { 
         charger17_parse_ic_status ( ic_status ); 
     } 
     if ( CHARGER17_OK == charger17_read_register ( &charger17, CHARGER17_REG_STAT0, &status_0 ) ) 
     { 
         charger17_parse_status_0 ( status_0 ); 
     } 
     Delay_ms ( 1000 ); 
 }

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager (recommended), downloaded from our LibStock™ or found on Mikroe github account.

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.Charger17

Additional notes and informations

Depending on the development board you are using, you may need USB UART click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all MikroElektronika compilers.

mikroSDK

This Click board™ is supported with mikroSDK - MikroElektronika Software Development Kit. To ensure proper operation of mikroSDK compliant Click board™ demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.

For more information about mikroSDK, visit the official page.