10 min

Control and limit the amount of electrical current with NPS4053 and STM32F429NI

Load switch with adjustable current limit

Current Limit 9 Click with Fusion for STM32 v8

Published Dec 13, 2023

Click board™

Current Limit 9 Click

Development board

Fusion for STM32 v8


NECTO Studio



Ensure that your projects receive the right amount of power and are protected from potential damage due to excessive current



Hardware Overview

How does it work?

Current Limit 9 Click is based on the NPS4053, a load switch with a precision adjustable current limit from Nexperia. It limits the output current to a constant current using a constant-current mode when the output load exceeds the current limit threshold or is shorted. An internal voltage comparator turns off the load switch to protect devices on the input side of the switch when the output voltage is higher than the input. The other protections include active reverse voltage protection, ILIM pin protection, ESD protection, and more. The current to which you can set the limit over the Current Limit 9 Click board™ can be

selected between external supply or 5V from the mikroBUS™ socket via the VIN SEL jumper. The external voltage can be in the range of 2.5 – 5.5V. It can use the MAX5419, a 256-tap 200K nonvolatile digital potentiometer from Analog Devices, to set the current limit threshold to the NPS4053 over the ILIM pin. It can also use an onboard R9 resistor for a fixed 0.5A at 5V supply. The selection can be made over the ILIM SEL. Current Limit 9 Click uses a standard 2-Wire I2C interface of the MAX5419 to allow the host MCU to set the desired current limit threshold, which supports a fast I2C interface. You can turn the

current limit IC on or off over the ON pin. The FLT is an interrupt pin, and it is asserted to a low logic level during overcurrent, overtemperature, and reverse-voltage conditions. 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.

Current Limit 9 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-M4

MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

Current Limit Enable
Power Supply
Fault Interrupt
I2C Clock
I2C Data
Power Supply

Take a closer look


Current Limit 9 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 Current Limit 9 Click driver.

Key functions:

  • currentlimit9_set_limit - This function sets the desired current limit threshold using the I2C serial interface.

  • currentlimit9_get_fault - This function gets the state of the fault flag to indicate overcurrent, overtemperature, or reverse-voltage conditions.

  • currentlimit9_enable - This function turns on the power switch and enables the internal MOSFET.

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 Current Limit 9 Click example
 * # Description
 * This library contains API for the Current Limit 9 Click driver.
 * This driver provides the functions to set the current limiting conditions 
 * in order to provide the threshold of the fault conditions.
 * The demo application is composed of two sections :
 * ## Application Init
 * Initialization of I2C module and log UART.
 * After driver initialization, the app executes a default configuration
 * and sets the current limit threshold of 460 mA.
 * ## Application Task
 * This example demonstrates the use of the Current Limit 9 Click board. 
 * The demo application checks the fault flag for overcurrent conditions.
 * Results are being sent to the UART Terminal, where you can track their changes.
 * @author Nenad Filipovic

#include "board.h"
#include "log.h"
#include "currentlimit9.h"

static currentlimit9_t currentlimit9;
static log_t logger;

void application_init ( void ) 
    log_cfg_t log_cfg;  /**< Logger config object. */
    currentlimit9_cfg_t currentlimit9_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.
    currentlimit9_cfg_setup( &currentlimit9_cfg );
    CURRENTLIMIT9_MAP_MIKROBUS( currentlimit9_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == currentlimit9_init( &currentlimit9, &currentlimit9_cfg ) ) 
        log_error( &logger, " Communication init." );
        for ( ; ; );
    if ( CURRENTLIMIT9_ERROR == currentlimit9_default_cfg ( &currentlimit9 ) )
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    if ( CURRENTLIMIT9_ERROR == currentlimit9_set_limit( &currentlimit9, CURRENTLIMIT9_LIMIT_0_46_A ) )
        log_error( &logger, " Current limit threshold." );
        for ( ; ; );
    log_info( &logger, " Application Task " );
    Delay_ms( 100 );

void application_task ( void ) 
    if ( CURRENTLIMIT9_FAULT_FLAG == currentlimit9_get_fault( &currentlimit9 ) )
        log_printf( &logger, "Fault flag: Overcurrent\r\n" );
        log_printf( &logger, " Current limit is 460 mA\r\n" );
    Delay_ms( 1000 );

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

    return 0;

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

Additional Support