30 min

Transform voltage like never before with MPM3530 and STM32L151ZD

Sync your power needs

Buck 13 Click with Fusion for STM32 v8

Published Aug 01, 2023

Click board™

Buck 13 Click

Dev Board

Fusion for STM32 v8


NECTO Studio



Ensure your electronics receive the necessary power, minimizing waste and enhancing performance



Hardware Overview

How does it work?

Buck 13 Click is based on the MPM3530, a 55V 3A ultra-low profile DC-to-DC power module by Monolithic Power Systems (MPS). This IC is a valley current mode controlled power module, meaning that it responds faster than the traditional peak current mode control, thus, a better response to transients. This IC requires minimal external components, making the whole device robust and easy to work with. The feedback voltage on the FB pin determines the output voltage. Therefore, Buck 13 click has a fixed voltage divider calculated to ensure stable, the most frequently used, 3.3V output. The MPM3530 operates at a high switching frequency of 520 kHz, which allows a good compromise between the efficiency and the device's size, with no external coil needed and a minimal number of other external components. This Click board™ also uses the MCP3001, a 10-bit A/D converter (ADC) which uses the SPI interface from Microchip. It allows monitoring of the

output voltage over the SPI interface. This ADC is powered by the +5V mikroBUS™ power rail. The same voltage is also used to supply the MCP1541 voltage reference. That way, the stable 4.096V reference voltage is obtained to ensure precise output voltage measurement. 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. The over-current protection is based on cycle-by-cycle limiting of the inductor current. If the output voltage starts to drop during the current limiting interval, causing the FB voltage to drop under 50% of the internal reference, the device enters the hiccup mode, shutting down the output. After a fixed period, the device will try to re-enable the output. If the short-circuit condition still exists, it will shut down the output again, repeating the whole process until the short-circuit condition disappears. The hiccup

mode greatly reduces the short-circuit current, protecting the device when the output is shorted to ground. Thanks to its ability to work with the high-duty cycle of the internal switching PWM signal, the MPM3530 requires the input voltage to be only about 0.7V above the output voltage to maintain the regulation. However, if the input voltage drops under 3.5V, the device cannot operate properly. Therefore, the under-voltage protection shuts down the device as a protection measure. The under-voltage protection is disabled once the input voltage exceeds 3.9V. This small hysteresis of 0.4V prevents erratic behavior in border cases. As mentioned before, the voltage of the power supply at the input terminal should stay within the range between 4V and 55V. However, the voltage at the input should be approximately 5.7V to 6V, at least, to provide good regulation at the output.

Buck 13 Click hardware overview image

Features overview

Development board

Fusion for STM32 v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports a wide range of microcontrollers, such as different 32-bit ARM® Cortex®-M based MCUs from STMicroelectronics, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over WiFi. 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. Thanks to innovative manufacturing technology, Fusion for STM32 v8 provides a fluid and immersive working experience, allowing

access anywhere and under any circumstances at any time. Each part of the Fusion for STM32 v8 development board contains the components necessary for the most efficient operation of the same board. An advanced integrated CODEGRIP programmer/debugger module offers many valuable programming/debugging options, including support for JTAG, SWD, and SWO Trace (Single Wire Output)), and seamless integration with the Mikroe software environment. Besides, it also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector.

Communication options such as USB-UART, USB HOST/DEVICE, CAN (on the MCU card, if supported), and Ethernet is also included. In addition, it also has the well-established mikroBUS™ standard, a standardized socket for the MCU card (SiBRAIN standard), and two display options for the TFT board line of products and character-based LCD. Fusion for STM32 v8 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.

Fusion for STM32 v8 horizontal image

Microcontroller Overview

MCU Card / MCU



8th Generation


ARM Cortex-M3

MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

SPI Chip Select
SPI Clock
Power Supply

Take a closer look


Buck 13 Click Schematic schematic

Step by step

Project assembly

Fusion for PIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Fusion for STM32 v8 as your development board.

Fusion for PIC v8 front image hardware assembly
GNSS2 Click front image hardware assembly
SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
v8 SiBRAIN Access MB 1 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
NECTO Compiler Selection Step Image hardware assembly
NECTO Output Selection Step Image hardware assembly
Necto image step 6 hardware assembly
Necto image step 7 hardware assembly
Necto image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto PreFlash Image hardware assembly

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.

UART Application Output Step 1

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.

UART Application Output Step 2

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".

UART Application Output Step 3

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.

UART Application Output Step 4

Software Support

Library Description

This library contains API for Buck 13 Click driver.

Key functions:

  • buck13_enable - Enables the Buck 13 output

  • buck13_get_adc - Gets the ADC values from the module

  • buck13_get_voltage - Gets the output voltage

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 
 * \brief Buck13 Click example
 * # Description
 * This example switches the output of the Buck13 and logs the output voltage 
 * on the Vout terminal.
 * The demo application is composed of two sections :
 * ## Application Init 
 * Initializes SPI serial interface and turns OFF the Buck 13 output as default state.
 * ## Application Task  
 * Displays the output voltage every 2 seconds.
 * *note:* 
 * Input voltage range must be from 6.5 to 50V.
 * Output voltage is about 3.3V.
 * Current limit is 3A.
 * \author Petar Suknjaja
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "buck13.h"

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

static buck13_t buck13;
static log_t logger;
static uint16_t out_voltage;

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

void application_init ( void )
    log_cfg_t log_cfg;
    buck13_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.

    buck13_cfg_setup( &cfg );
    buck13_default_cfg ( &buck13 );
    buck13_init( &buck13, &cfg );
    log_info( &logger, "Buck 13 is enabled now" );

void application_task ( void )
    //  Task implementation.

    buck13_enable( &buck13, BUCK13_ENABLE ); 
    out_voltage = buck13_get_voltage( &buck13 );
    log_printf( &logger, "Vout =  %d mV\r\n", out_voltage );
    Delay_ms( 2000 );

void main ( void )
    application_init( );

    for ( ; ; )
        application_task( );

// ------------------------------------------------------------------------ END

Additional Support