Achieve fast-charging of various rechargeable batteries with LT1571 and STM32F407VGT6
Charge like a pro!
Published May 14, 2023
Click board™
Charger 16 Click
Dev Board
EasyMx PRO v7a for STM32
Compiler
NECTO Studio
MCU
STM32F407VGT6
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
EasyMx PRO v7a for STM32 is the seventh generation of ARM development boards specially designed to develop embedded applications rapidly. It supports a wide range of 32-bit ARM microcontrollers from STMicroelectronics and a broad set of unique functions, such as the first-ever embedded debugger/programmer over USB-C. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. With two different connectors for each port, EasyMx PRO v7afor STM32 allows you to connect accessory boards, sensors, and custom electronics more efficiently than ever. Each part of the EasyMx
PRO v7a for STM32 development board contains the components necessary for the most efficient operation of the same board. In addition to the advanced integrated CODEGRIP programmer/debugger module, which offers many valuable programming/debugging options and seamless integration with the Mikroe software environment, the board also includes a clean and regulated power supply block for the development board. It can use a wide range of external power sources, including an external 12V power supply, 7-23V AC or 9-32V DC via DC connector/screw terminals, and a power source via the USB Type-C (USB-C) connector. Communication options such as USB-UART, USB-HOST/DEVICE, CAN, and
Ethernet are also included, including the well-established mikroBUS™ standard, one display option for the TFT board line of products, and a standard TQFP socket for the seventh-generation MCU cards. This socket covers 32-bit ARM MCUs like STM32 Cortex-M3, -M7, and -M4 MCUs. EasyMx PRO v7afor STM32 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.
Microcontroller Overview
MCU Card / MCU
Type
7th Generation
Architecture
ARM Cortex-M4
MCU Memory (KB)
10
Silicon Vendor
STMicroelectronics
Pin count
100
RAM (Bytes)
100
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
Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the EasyMx PRO v7a for STM32 as your development board.
Track your results in real time
Application Output
After pressing the "FLASH" button on the left-side panel, it is necessary to open the UART terminal to display the achieved results. By clicking on the Tools icon in the right-hand panel, multiple different functions are displayed, among which is the UART Terminal. Click on the offered "UART Terminal" icon.
Once the UART terminal is opened, the window takes on a new form. At the top of the tab are two buttons, one for adjusting the parameters of the UART terminal and the other for connecting the UART terminal. The tab's lower part is reserved for displaying the achieved results. Before connecting, the terminal has a Disconnected status, indicating that the terminal is not yet active. Before connecting, it is necessary to check the set parameters of the UART terminal. Click on the "OPTIONS" button.
In the newly opened UART Terminal Options field, we check if the terminal settings are correct, such as the set port and the Baud rate of UART communication. If the data is not displayed properly, it is possible that the Baud rate value is not set correctly and needs to be adjusted to 115200. If all the parameters are set correctly, click on "CONFIGURE".
The next step is to click on the "CONNECT" button, after which the terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.
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
This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.
/*!
* @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 );
Delay_ms( 10000 );
log_printf( &logger, "------------------\r\n" );
log_printf( &logger, " Disable charging \r\n" );
charger16_disable_charging( &charger16 );
Delay_ms( 10000 );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
