Transform voltage like never before with MPM3530 and PIC18F4515

Sync your power needs

Published Nov 01, 2023

Click board™

Buck 13 Click

Dev Board

EasyPIC v8

Compiler

NECTO Studio

MCU

PIC18F4515

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.

Features overview

Development board

EasyPIC v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports many high pin count 8-bit PIC microcontrollers from Microchip, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer. 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, EasyPIC v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the EasyPIC v8 development board contains the components necessary for the most efficient operation of the same board. In addition to the advanced integrated CODEGRIP programmer/debugger module, which offers many valuable programming/debugging options and seamless integration with the Mikroe software environment, the board 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 DEVICE, and CAN are also included, including the well-established mikroBUS™ standard, two display options (graphical and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from the smallest PIC MCU devices with only eight up to forty pins. EasyPIC 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.

Microcontroller Overview

MCU Card / MCU

Architecture

PIC

MCU Memory (KB)

Silicon Vendor

Microchip

Pin count

RAM (Bytes)

3968

Used MCU Pins

mikroBUS™ mapper

Enable

RA2

RST

SPI Chip Select

RE0

SPI Clock

RC3

SCK

SPI Data OUT

RC4

MISO

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

EasyPIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v8 as your development board.

NECTO Output Selection Step Image hardware assembly

In the advanced settings, pay special attention to the Redirect standard output field. By default, it is set to Application output as the method of displaying final results. To show results via a UART terminal, select the “UART” option in that field and click the “SAVE” button. You will be returned to the Compiler field, and now you can move on to the next step by pressing the “NEXT” button.

GNSS2 Click front image hardware assembly

GNSS2 Click complete accessories setup image hardware assembly

EasyPIC v8 Access DIPMB 1 - upright/background hardware assembly

NECTO Compiler Selection Step Image hardware assembly

Necto DIP image step 7 hardware assembly

Track your results in real time

Application Output

This Click board can be interfaced and monitored in two ways:

Application Output - Use the "Application Output" window in Debug mode for real-time data monitoring. Set it up properly by following this tutorial.

UART Terminal - Monitor data via the UART Terminal using a USB to UART converter. For detailed instructions, check out this tutorial.

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

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 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_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    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