Achieve fast-charging of various rechargeable batteries with LT1571 and STM32L496AG
Charge like a pro!
Published Jul 22, 2025
Click board™
Charger 16 Click
Dev. board
Discovery kit with STM32L496AG MCU
Compiler
NECTO Studio
MCU
STM32L496AG
Get the best of both worlds - add a high-performance battery charger to your solution that is both affordable and reliable
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Hardware Overview
How does it work?
Charger 16 Click is based on 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 or constant-voltage control. The internal switch can deliver a 1.5A DC (2A peak current). A saturating switch operates at 500kHz, which provides high efficiency and a small charger size. Charger 16 Click 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 with 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 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™ can only be operated with a 5V 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.
Features overview
Development board
The 32L496GDISCOVERY Discovery kit serves as a comprehensive demonstration and development platform for the STM32L496AG microcontroller, featuring an Arm® Cortex®-M4 core. Designed for applications that demand a balance of high performance, advanced graphics, and ultra-low power consumption, this kit enables seamless prototyping for a wide range of embedded solutions. With its innovative energy-efficient
architecture, the STM32L496AG integrates extended RAM and the Chrom-ART Accelerator, enhancing graphics performance while maintaining low power consumption. This makes the kit particularly well-suited for applications involving audio processing, graphical user interfaces, and real-time data acquisition, where energy efficiency is a key requirement. For ease of development, the board includes an onboard ST-LINK/V2-1
debugger/programmer, providing a seamless out-of-the-box experience for loading, debugging, and testing applications without requiring additional hardware. The combination of low power features, enhanced memory capabilities, and built-in debugging tools makes the 32L496GDISCOVERY kit an ideal choice for prototyping advanced embedded systems with state-of-the-art energy efficiency.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M4
MCU Memory (KB)
1024
Silicon Vendor
STMicroelectronics
Pin count
169
RAM (Bytes)
327680
You complete me!
Accessories
Li-Polymer Battery is the ideal solution for devices that demand a dependable and long-lasting power supply while emphasizing mobility. Its compatibility with mikromedia boards ensures easy integration without additional modifications. With a voltage output of 3.7V, the battery meets the standard requirements of many electronic devices. Additionally, boasting a capacity of 2000mAh, it can store a substantial amount of energy, providing sustained power for extended periods. This feature minimizes the need for frequent recharging or replacement. Overall, the Li-Polymer Battery is a reliable and autonomous power source, ideally suited for devices requiring a stable and enduring energy solution. You can find a more extensive choice of Li-Polymer batteries in our offer.
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Discovery kit with STM32L496AG MCU as your development board.
Track your results in real time
Application Output
1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.
2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.
3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.
Software Support
Library Description
This library contains API for Charger 16 Click driver.
Key functions:
charger16_cfg_setup- Config Object Initialization function.charger16_init- Initialization function.charger16_default_cfg- Click Default Configuration function.
Open Source
Code example
The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.
/*!
* @file main.c
* @brief Charger 16 Click Example.
*
* # Description
* This library contains API for the Charger 16 Click driver.
* This demo application shows use of a Charger 16 Click board™.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initialization of GPIO module and log UART.
* After driver initialization the app set default settings.
*
* ## Application Task
* This is an example that shows the use of an Charger 16 Click board™.
* The app turns the battery charge on and off every 10 seconds.
* Results are being sent to the Usart Terminal where you can track their changes.
*
* @author Nenad Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "charger16.h"
static charger16_t charger16; /**< Charger 16 Click driver object. */
static log_t logger; /**< Logger object. */
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
charger16_cfg_t charger16_cfg; /**< Click config object. */
/**
* Logger initialization.
* Default baud rate: 115200
* Default log level: LOG_LEVEL_DEBUG
* @note If USB_UART_RX and USB_UART_TX
* are defined as HAL_PIN_NC, you will
* need to define them manually for log to work.
* See @b LOG_MAP_USB_UART macro definition for detailed explanation.
*/
LOG_MAP_USB_UART( log_cfg );
log_init( &logger, &log_cfg );
log_info( &logger, " Application Init " );
// Click initialization.
charger16_cfg_setup( &charger16_cfg );
CHARGER16_MAP_MIKROBUS( charger16_cfg, MIKROBUS_1 );
if ( charger16_init( &charger16, &charger16_cfg ) == DIGITAL_OUT_UNSUPPORTED_PIN )
{
log_error( &logger, " Application Init Error. " );
log_info( &logger, " Please, run program again... " );
for ( ; ; );
}
charger16_default_cfg ( &charger16 );
log_info( &logger, " Application Task " );
Delay_ms ( 100 );
}
void application_task ( void )
{
log_printf( &logger, "-----------------\r\n" );
log_printf( &logger, " Enable charging \r\n" );
charger16_enable_charging( &charger16 );
// 10 seconds delay
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
log_printf( &logger, "------------------\r\n" );
log_printf( &logger, " Disable charging \r\n" );
charger16_disable_charging( &charger16 );
// 10 seconds delay
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
}
int main ( void )
{
/* Do not remove this line or clock might not be set correctly. */
#ifdef PREINIT_SUPPORTED
preinit();
#endif
application_init( );
for ( ; ; )
{
application_task( );
}
return 0;
}
// ------------------------------------------------------------------------ END
Additional Support
Resources
Category:Battery charger
