Ensure optimal power delivery with LT3976 and STM32F302VC
Step down, Power up!
Published Jul 22, 2025
Click board™
BUCK Click
Dev. board
CLICKER 4 for STM32F302VCT6
Compiler
NECTO Studio
MCU
STM32F302VC
With its compact design and high efficiency, our step-down buck converter is the go-to solution for portable electronic devices, extending battery life while maintaining performance
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Hardware Overview
How does it work?
BUCK Click is based on the LT3976, a buck switching regulator from Analog Devices that accepts a wide input voltage range of up to 40V and steps it down to 3.3V or 5V. BUCK Click communicates with the target microcontroller over the following pins on the mikroBUS™ line: PWM, INT, RS, CS. The LT3976 is an adjustable frequency monolithic buck-switching regulator that accepts a wide input voltage range of up to 40V. Low quiescent current design consumes only
3.3µA of supply current while regulating with no load. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping the output ripple below 15mV in a typical application. The LT3976 can supply up to 5A of load current and has current limit foldback to limit power dissipation during short-circuit. A low dropout voltage of 500mV is maintained when the input voltage drops below the programmed output voltage, such as during an automotive cold
crank. There are two onboard screw terminals, one for connecting the external input supply and the other for the output. A multiplexer also chooses the resistor used for setting the switching frequency. The multiplexer is used for selecting one of the four different resistors. Each of these resistors, if selected, sets a different switching frequency from 0.4 to 1.6MHz.
Features overview
Development board
Clicker 4 for STM32F3 is a compact development board designed as a complete solution, you can use it to quickly build your own gadgets with unique functionalities. Featuring a STM32F302VCT6, four mikroBUS™ sockets for Click boards™ connectivity, power managment, and more, it represents a perfect solution for the rapid development of many different types of applications. At its core, there is a STM32F302VCT6 MCU, a powerful microcontroller by STMicroelectronics, based on the high-
performance Arm® Cortex®-M4 32-bit processor core operating at up to 168 MHz frequency. It provides sufficient processing power for the most demanding tasks, allowing Clicker 4 to adapt to any specific application requirements. Besides two 1x20 pin headers, four improved mikroBUS™ sockets represent the most distinctive connectivity feature, allowing access to a huge base of Click boards™, growing on a daily basis. Each section of Clicker 4 is clearly marked, offering an intuitive and clean interface. This makes working with the development
board much simpler and thus, faster. The usability of Clicker 4 doesn’t end with its ability to accelerate the prototyping and application development stages: it is designed as a complete solution which can be implemented directly into any project, with no additional hardware modifications required. Four mounting holes [4.2mm/0.165”] at all four corners allow simple installation by using mounting screws. For most applications, a nice stylish casing is all that is needed to turn the Clicker 4 development board into a fully functional, custom design.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M4
MCU Memory (KB)
256
Silicon Vendor
STMicroelectronics
Pin count
100
RAM (Bytes)
40960
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 CLICKER 4 for STM32F302VCT6 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 BUCK Click driver.
Key functions:
buck_switch_frequency- Setting the switching frequency functionbuck_set_mode- Select buck mode (Disable / Enable)buck_get_power_good- Get state internal comparator 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
* \brief BUCK Click example
*
* # Description
* The demo application displays frequency change and voltage
* regulation using a BUCK Click.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Configuring Clicks and log objects.
* Settings the Click in the default configuration.
*
* ## Application Task
* This is a example which demonstrates the use of Buck Click board.
* Checks if it has reached the set output voltage and sets
* a different frequency to the LT3976 chip every 5 sec.
*
* \author Katarina Perendic
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "buck.h"
// ------------------------------------------------------------------ VARIABLES
static buck_t buck;
static log_t logger;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
buck_cfg_t cfg;
/**
* 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.
buck_cfg_setup( &cfg );
BUCK_MAP_MIKROBUS( cfg, MIKROBUS_1 );
buck_init( &buck, &cfg );
Delay_ms ( 100 );
buck_device_reset( &buck );
buck_default_cfg( &buck );
}
void application_task ( void )
{
// Task implementation.
if ( buck_get_power_good( &buck ) == 1 )
{
log_info( &logger, "---- Power good output voltage! ----" );
}
Delay_ms ( 1000 );
log_info( &logger, "---- Switching frequency 400kHz! ----" );
buck_switch_frequency( &buck, BUCK_FREQ_400KHz );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
log_info( &logger, "---- Switching frequency 800kHz! ----" );
buck_switch_frequency( &buck, BUCK_FREQ_800KHz );
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:Buck
