Convert and regulate voltage levels with TPS55289 and PIC18F2455

Synchronous buck-boost converter optimized for USB power delivery (USB PD) application

Published Feb 06, 2024

Click board™

Buck-Boost 4 Click

Dev. board

EasyPIC v7a

Compiler

NECTO Studio

MCU

PIC18F2455

Take in one voltage and convert it to a higher or lower voltage as needed, making it useful for various applications that require different power levels

Hardware Overview

How does it work?

Buck-Boost 4 Click is based on the TPS55289, a buck-boost converter from Texas Instruments. It can smoothly transition between buck mode, buck-boost mode, and boost mode according to the input voltage and the set output voltage. It operates in buck mode when the input voltage exceeds the output voltage and in boost mode when the input voltage is less than the input voltage. When the input voltage is close to the output voltage, it

alternates between one-cycle buck mode and one-cycle boost mode. The converter can work in PWM or PFM mode, depending on the load currents. The switching frequency is set with a resistor to a little less than 1MHz. Buck-Boost 4 Click uses a standard 2-wire I2C interface to communicate with the host MCU supporting clock frequency of up to 1MHz. The I2C address can be selected over the ADDR SEL jumper. You can turn off the device by

setting the EN pin to a LOW logic state. The fault indication is available over the INT pin. 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 for further development.

Buck-Boost 4 Click hardware overview image

Features overview

Development board

EasyPIC v7a is the seventh generation of PIC development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 8-bit PIC microcontrollers from Microchip and has a broad set of unique functions, such as the first-ever embedded debugger/programmer over USB-C. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyPIC v7a allows you to connect accessory boards, sensors, and custom electronics more efficiently than ever. Each part of the EasyPIC v7a 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 various external power sources, including an external 12V power supply, 7-23V AC or 9-32V DC via DC connector/screw terminals, and a power source via the USB Type-C (USB-C) connector. Communication options such as USB-UART and RS-232 are also included, alongside the well-

established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from PIC10F, PIC12F, PIC16F, PIC16Enh, PIC18F, PIC18FJ, and PIC18FK families. EasyPIC v7a 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)

2048

Used MCU Pins

mikroBUS™ mapper

RST

ID COMM

RA5

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

Device Enable

RC1

PWM

Interrupt

RB1

INT

I2C Clock

RC3

SCL

I2C Data

RC4

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

EasyPIC v7a front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v7a 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.

LTE IoT 5 Click front image hardware assembly

LTE IoT 5 Click complete accessories setup image hardware assembly

EasyPIC v7a Access MB 2 - upright/background hardware assembly

NECTO Compiler Selection Step Image hardware assembly

Necto DIP image step 7 hardware assembly

EasyPIC PRO v7a Display Selection Necto Step 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-Boost 4 Click driver.

Key functions:

buckboost4_set_vout - Buck-Boost 4 set the output voltage function
buckboost4_set_vref - Buck-Boost 4 set internal reference voltage function
buckboost4_fault_indicator - Buck-Boost 4 check fault indicator function

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 main.c
 * @brief Buck-Boost 4 Click example
 *
 * # Description
 * This example demonstrates the use of the Buck-Boost 4 Click board™.
 * This driver provides functions for device configurations and for the sets the output voltage.
 *
 * 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.
 *
 * ## Application Task
 * The demo application sets the desired output voltage 
 * by cycling through a couple of voltage values.
 * Results are sent to the UART Terminal, where you can track their changes.
 *
 * @author Nenad Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "buckboost4.h"

static buckboost4_t buckboost4;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    buckboost4_cfg_t buckboost4_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.
    buckboost4_cfg_setup( &buckboost4_cfg );
    BUCKBOOST4_MAP_MIKROBUS( buckboost4_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == buckboost4_init( &buckboost4, &buckboost4_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( BUCKBOOST4_ERROR == buckboost4_default_cfg ( &buckboost4 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
    log_printf( &logger, "____________\r\n" );
    Delay_ms( 100 );
}

void application_task ( void ) 
{
    for ( uint8_t vout = 1; vout < 21; vout++ )
    {
        if ( BUCKBOOST4_OK == buckboost4_set_vout( &buckboost4, ( float ) vout ) )
        {
            log_printf( &logger, " Vout: %dV\r\n", ( uint16_t ) vout );
            Delay_ms( 5000 );
        }
    }
    log_printf( &logger, "____________\r\n" );
    Delay_ms( 1000 );
}

void main ( void ) 
{
    application_init( );

    for ( ; ; ) 
    {
        application_task( );
    }
}

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