10 min

Provide a stable, reduced voltage from a higher input voltage source using TPS62903 and PIC18F47K42TQFP

AEC-Q100 qualified synchronous step-down (buck) DC/DC converter

Buck 15 Click with Curiosity Nano with PIC18F47K42

Published Mar 07, 2024

Click board™

Buck 15 Click

Dev Board

Curiosity Nano with PIC18F47K42


NECTO Studio



Lower and stabilize the voltage for various systems requiring reliable power management, such as ADAS, body electronics, lighting, and infotainment, ensuring they operate smoothly and safely



Hardware Overview

How does it work?

Buck 15 Click is based on the TPS62903, a synchronous step-down DC/DC converter from Texas Instruments, recognized for its high efficiency, compact size, and adaptability. This converter stands out for its rapid transient response and supports a high output voltage accuracy of ±1.5% across the entire operating temperature range. It employs the DCS-control topology to enhance load transient performance, and its broad input voltage range accommodates various power sources, including 12V supply rails, single-cell or multi-cell Li-Ion batteries, and 5V or 3.3V power rails. Notably, the TPS62903 is designed to automatically enter power save mode under light load conditions, ensuring high efficiency and a low quiescent current of 4µA to optimize performance even at minimal loads. Communication with the Buck 15 Click is conducted through a standard 2-wire interface linked to the AD5242, allowing the

host MCU to adjust the output voltage. The device's I2C address is configurable via the ADDR SEL jumper, with a default setting of 0. This Click board™ also features a power-good (PG) pin that indicates when the output voltage falls outside the predetermined window threshold and an EN pin, which serves as a precision regulator-enable input. Besides these pins, the TPS62903 also has a MODE/Smart-CONF pin, allowing for comprehensive customization of operational parameters such as the internal and external divider, switching frequency, output voltage discharge, and the mode of operation between automatic power save and forced PWM. An 11k R11 resistor setting achieves a 1MHz switching frequency, enabled output discharge, and Auto PFM/PWM Mode. The output voltage is adjustable from 0.4V to 5V, supporting currents up to 3A, enabled by an onboard digital potentiometer, the

AD5242. Buck 15 Click also offers versatile power sourcing options, allowing users to choose between internal and external supplies to suit their application needs best. This flexibility is achieved through the VIN SEL jumper, which enables users to select the VCC position for sourcing power internally via the mikroBUS™ power rails or the VEXT position to connect an external power supply. The external power supply can range from 3V to 17V, providing a broad voltage range for various project requirements. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Also, this Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used as a reference for further development.

Buck 15 Click hardware overview image

Features overview

Development board

PIC18F47K42 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate the PIC18F47K42 microcontroller (MCU). Central to its design is the inclusion of the powerful PIC18F47K42 microcontroller (MCU), offering advanced functionalities and robust performance. Key features of this evaluation kit include a yellow user LED and a responsive mechanical user switch

providing seamless interaction and testing. The provision for a 32.768kHz crystal footprint ensures precision timing capabilities. With an onboard debugger boasting a green power and status LED, programming and debugging become intuitive and efficient. Further enhancing its utility is the Virtual serial port (CDC) and a debug GPIO channel (DGI GPIO), offering extensive connectivity options.

Powered via USB, this kit boasts an adjustable target voltage feature facilitated by the MIC5353 LDO regulator, ensuring stable operation with an output voltage ranging from 2.3V to 5.1V (limited by USB input voltage), with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.

PIC18F47K42 Curiosity Nano double side image

Microcontroller Overview

MCU Card / MCU




MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


You complete me!


Curiosity Nano Base for Click boards is a versatile hardware extension platform created to streamline the integration between Curiosity Nano kits and extension boards, tailored explicitly for the mikroBUS™-standardized Click boards and Xplained Pro extension boards. This innovative base board (shield) offers seamless connectivity and expansion possibilities, simplifying experimentation and development. Key features include USB power compatibility from the Curiosity Nano kit, alongside an alternative external power input option for enhanced flexibility. The onboard Li-Ion/LiPo charger and management circuit ensure smooth operation for battery-powered applications, simplifying usage and management. Moreover, the base incorporates a fixed 3.3V PSU dedicated to target and mikroBUS™ power rails, alongside a fixed 5.0V boost converter catering to 5V power rails of mikroBUS™ sockets, providing stable power delivery for various connected devices.

Curiosity Nano Base for Click boards accessories 1 image

Used MCU Pins

mikroBUS™ mapper

Power Supply
Module Power-Up
Power-Good Indicator
I2C Clock
I2C Data
Power Supply

Take a closer look


Buck 15 Click Schematic schematic

Step by step

Project assembly

Curiosity Nano Base for Click boards accessories 1 image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity Nano with PIC18F47K42 as your development board.

Curiosity Nano Base for Click boards accessories 1 image hardware assembly
Charger 27 Click front image hardware assembly
PIC18F47K42 Curiosity Nano front image hardware assembly
Prog-cut hardware assembly
Charger 27 Click complete accessories setup image hardware assembly
Curiosity Nano with PIC18F47XXX 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 image step 5 hardware assembly
Necto image step 6 hardware assembly
PIC18F57Q43 Curiosity MCU Step hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image Necto Step hardware assembly

Track your results in real time

Application Output

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

Software Support

Library Description

This library contains API for Buck 15 Click driver.

Key functions:

  • buck15_set_vout - This function sets the voltage output by using an I2C serial interface

  • buck15_set_vset - This function sets the wiper position for the output voltage settings by using an I2C serial interface

  • buck15_enable_device - This function enables the device by setting the EN pin to high logic state

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 Buck 15 Click example
 * # Description
 * This example demonstrates the use of the Buck 15 Click board by changing the output voltage.
 * The demo application is composed of two sections :
 * ## Application Init
 * Initializes the driver and performs the device default configuration.
 * ## Application Task
 * The demo application changes the output voltage and displays the currently set voltage output value.
 * Results are being sent to the UART Terminal, where you can track their changes.
 * @author Nenad Filipovic

#include "board.h"
#include "log.h"
#include "buck15.h"

static buck15_t buck15;
static log_t logger;

// Output voltage data table
static float vout_table[ 22 ] = { BUCK15_VOUT_TABLE };

void application_init ( void ) 
    log_cfg_t log_cfg;  /**< Logger config object. */
    buck15_cfg_t buck15_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.
    buck15_cfg_setup( &buck15_cfg );
    BUCK15_MAP_MIKROBUS( buck15_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == buck15_init( &buck15, &buck15_cfg ) ) 
        log_error( &logger, " Communication init." );
        for ( ; ; );
    if ( BUCK15_ERROR == buck15_default_cfg ( &buck15 ) )
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    log_info( &logger, " Application Task " );
    log_printf( &logger, "____________\r\n" );
    Delay_ms( 100 );

void application_task ( void ) 
    for ( buck15_vout_t vout = BUCK15_VOUT_0V6; vout <= BUCK15_VOUT_5V; vout++ )
        if ( BUCK15_OK == buck15_set_vout( &buck15, vout ) )
            log_printf( &logger, " Vout : %.1f [V]\r\n", vout_table[ vout ] );
            log_printf( &logger, "____________\r\n" );
            Delay_ms( 5000 );

int main ( void ) 
    application_init( );
    for ( ; ; ) 
        application_task( );

    return 0;

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

Additional Support