Achieve some serious voltage step-down brilliance with MPQ8632 and STM32L496AG

Synchronous step-down magic!

Buck 12 Click with Discovery kit with STM32L496AG MCU

Published Jul 22, 2025

Click board™

Buck 12 Click

Dev. board

Discovery kit with STM32L496AG MCU

Compiler

NECTO Studio

MCU

STM32L496AG

Compact and versatile, our buck step-down converter is essential in portable devices, extending battery life and enhancing usability

Hardware Overview

How does it work?

Buck 12 Click is based on the MPQ8632, a synchronous step-down converter from Monolithic Power Systems (MPS). This advanced integrated step-down converter requires a minimum number of external components readily available on the market. It utilizes a peak-current-mode control architecture, ensuring good efficiency and automatic switch-mode switching. The MPQ8632 buck converter features over-current, under-voltage, and thermal protection, making Buck 12 click a robust and reliable power supply solution. The feedback voltage on the FB pin determines the output voltage. The output voltage is set to 3.3V, making it usable with most embedded applications, allowing them to be powered from the same source, like the rest of the application, which may use a higher voltage for its operation. This is a common-case scenario in various field applications requiring a relatively high voltage, i.e., for servos, step motors, displays, and more. When there is an overload at the output, the low-side MOSFET will allow the inductor current to drop.

It will remain open until the current through the inductor falls below the limit. Suppose the FB voltage drops too much during the overload. In that case, the device enters the hiccup mode, which turns off the output power stage, discharges the soft-start capacitor, and automatically retries the soft-start. The MPQ8632 can automatically switch between different operating modes, depending on the current through the load. At very light loads, the device is operated in skip mode. In this mode, HS-FET turns on for a fixed interval determined by the one-shot on-timer. When the HS-FET turns off, the LS-FET turns on until the inductor current reaches zero. The LS-FET driver turns into a tri-state (high Z) whenever the inductor current reaches zero. This way, the device is idle while the light load consumes energy stored within the coil. This greatly improves the efficiency when a light load is used. This is also called discontinuous conduction mode (DCM). The MPQ8632 automatically switches to heavy load operation or continuous

conduction mode (CCM) when heavily loaded. In this mode, when VFB is below VREF, HS-FET turns on for a fixed interval determined by the one-shot on-timer. When the HS-FET turns off, the LS-FET turns on until the next period. In CCM operation, the switching frequency is fairly constant and called PWM mode. Packed in QFN casing (3X4mm), the MPQ8632 occupies a small area on the PCB. Combined with the low count of external components it requires, the MPQ8632 leaves enough space for an additional IC to be used. This click uses the MCP3202, a Dual Channel 12-Bit A/D Converter which uses the SPI interface from Microchip. It allows monitoring of the input and output voltages over the SPI interface. This ADC is powered by the +5V mikroBUS™ power rail. The same voltage is used as a reference. The Click board™ itself requires an external power supply to be connected at the input terminal, labeled as VIN. The VOUT terminal provides the connected load with the regulated 3.3V voltage.

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.

Discovery kit with STM32L496AG MCU double side image

Microcontroller Overview

MCU Card / MCU

Architecture

ARM Cortex-M4

MCU Memory (KB)

1024

Silicon Vendor

STMicroelectronics

Pin count

169

RAM (Bytes)

327680

Used MCU Pins

mikroBUS™ mapper

Enable

PB2

RST

SPI Chip Enable

PG11

SPI Clock

PI1

SCK

SPI Data OUT

PD3

MISO

SPI Data IN

PI3

MOSI

3.3V

Ground

GND

PWM

INT

SCL

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

Discovery kit with STM32H750XB MCU front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Discovery kit with STM32L496AG MCU as your development board.

Thermo 21 Click front image hardware assembly

Thermo 21 Click complete accessories setup image hardware assembly

Board mapper by product7 hardware assembly

Discovery kit with STM32H750XB MCU NECTO MCU Selection Step hardware assembly

Necto No Display image step 8 hardware assembly

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 12 Click driver.

Key functions:

buck12_control - This function for enable or disable device
buck12_get_channel_adc - This function reads ADC on the channel
buck12_get_voltage - This function gets voltage

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 Buck12 Click example
 * 
 * # Description
 * This demo application reads the voltage in [mV] at the input and output terminals.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Configuring Clicks and log objects.
 * 
 * ## Application Task  
 * Reads the voltage in [mV] at the input and output terminals.
 * This data logs to the USBUART every 2 sec.
 *
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "buck12.h"

// ------------------------------------------------------------------ VARIABLES

static buck12_t buck12;
static log_t logger;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    buck12_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.

    buck12_cfg_setup( &cfg );
    BUCK12_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    buck12_init( &buck12, &cfg );

    buck12_control( &buck12, BUCK12_ENABLE );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
}

void application_task ( void )
{
    float voltage;

    voltage = buck12_get_voltage( &buck12, BUCK12_INPUT_VOLTAGE );
    
    log_printf( &logger, "* Vin : %f mV \r\n ", voltage);
    voltage = buck12_get_voltage( &buck12, BUCK12_OUTPUT_VOLTAGE );

    log_printf( &logger, "* Vout : %f mV \r\n ", voltage);
    log_printf( &logger, "--------------------------\r\n");
    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