Solve every voltage challenge with LTC3115-2 and PIC18F57Q43

Boost or buck, your choice!

Buck-Boost 2 Click with Curiosity Nano with PIC18F57Q43

Published Feb 13, 2024

Click board™

Buck-Boost 2 Click

Dev. board

Curiosity Nano with PIC18F57Q43

Compiler

NECTO Studio

MCU

PIC18F57Q43

Revolutionize your energy management with our avant-garde Buck-Boost combo at your side

Hardware Overview

How does it work?

Buck-Boost 2 Click is based on the LTC3115-2, a 40V, 2A synchronous buck-boost DC/DC converter from Analog Devices. This IC relies on the advanced four MOSFET switch topology, so it can sustain the regulation when the input voltage is lower and higher than the output voltage, set by the feedback network to 5V. A proprietary switching algorithm ensures a transparent, continuous transition between operating modes. The LTC3115-2 features both forward and reverse current limiting sections. The maximum current available on the output depends on the mode of operation: If the output voltage is greater than the input voltage, the device works in boost mode, and the maximum current is about 0.6A. If the output voltage exceeds the input voltage, the device works in buck mode, and the maximum current available is about 1.4A. Also, the maximum output current is affected by the switching mode, selectable by the MODE pin, routed to the PWM pin of the mikroBUS™. There are two modes available: fixed frequency PWM mode and burst mode. While working in PWM mode, the LTC3115-2 IC uses a fixed frequency determined by the onboard resistor - in the case of the Buck-Boost 2 click, it is fixed at 750kHz. The PWM mode is used when a heavier load is connected to the output

terminal. This mode is set when the PWM/SYNC pin is pulled to a HIGH logic level. This mode allows the maximum current on the output and results in the lowest amount of switching noise and output voltage ripple. This mode provides power for the connected devices while they work in the active mode. The burst mode is used for maintained efficiency when light output loads are used. When the PWM/SYNC pin is pulled to a LOW logic level, the device will work in burst mode. While in burst mode, the variable frequency switching algorithm is used, resulting in a low quiescent current, which allows lowered power consumption - e.g., when the external voltage input is taken from a battery. The error amplifier is powered down in this mode, and the output current should not be greater than allowed, else the output voltage will lose regulation. This mode is perfectly suited to power up various devices while they work in standby mode. When using the synchronization function of the PWM/SYNC pin, the device works in the fixed frequency PWM mode, but the external clock source of the internal PLL section regulates its frequency. This can be useful when special power supply noise requirements must be met. Since the internal PLL can only increase the internal clock frequency, the

external clock signal should be above the frequency set by the onboard resistor (750kHz), taking the sufficient error margin into account. The RUN pin of the LTC3115-2 IC is routed to the mikroBUS™ RST pin and is used to activate the internal logic and switching circuitry. Setting this pin to a HIGH logic level (above 1.21V) will enable both the logic and the switching sections of the LTC3115-2 IC. It is possible to measure and monitor the output voltage of the Buck-Boost 2 by utilizing the voltage divider, with its middle point routed to the AN pin of the mikroBUS™. By applying the calculation from the formula below, it is possible to determine the exact value of the output voltage. It can monitor the output to take appropriate action when the voltage drops or loses regulation. This board allows operation with both 3.3V and 5V MCUs. There is an onboard SMD jumper labeled as VCC SEL, which is used to set the logic voltage (e.g., for the RUN pin) and the input voltage for the LTC3115-2 IC. Another SMD jumper, labeled VIN SEL, selects the voltage chosen by the VCC SEL and the external source connected to the input terminal. The output load should be connected to the output terminal. Two screw terminals allow easy and secure connection of the input and output lines.

Buck-Boost 2 Click hardware overview image

Features overview

Development board

PIC18F57Q43 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate microcontrollers within the PIC18-Q43 family. Central to its design is the inclusion of the powerful PIC18F57Q43 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 1.8V to 5.1V, with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.

PIC18F57Q43 Curiosity Nano double side image

Microcontroller Overview

MCU Card / MCU

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

RAM (Bytes)

8196

You complete me!

Accessories

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.

Used MCU Pins

mikroBUS™ mapper

Analog Output

PA0

Chip Enable

PA7

RST

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

PWM Signal/Burst Mode

PB0

PWM

INT

SCL

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

Curiosity Nano Base for Click boards front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity Nano with PIC18F57Q43 as your development board.

Charger 27 Click front image hardware assembly

PIC18F47Q10 Curiosity Nano front image hardware assembly

Charger 27 Click complete accessories setup image hardware assembly

Board mapper by product8 hardware assembly

PIC18F57Q43 Curiosity MCU Step hardware assembly

Necto No Display image step 8 hardware assembly

Debug Image 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 2 Click driver.

Key functions:

buckboost2_set_mode - This function sets the working mode
buckboost2_power_off - This function powers OFF the chip
buckboost2_power_on - This function powers on the chip

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 Buck Boost 2 Click example
 * 
 * # Description
 * This application enables use of DC-DC step-down/step-up regulator (buck/boost).
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes Driver init and turn ON chip and settings mode with improvement current.
 * 
 * ## Application Task  
 * The Click has a constant output voltage of 5V, no additional settings are required.
 * 
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "buckboost2.h"

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

static buckboost2_t buckboost2;
static log_t logger;

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    buckboost2_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.

    buckboost2_cfg_setup( &cfg );
    BUCKBOOST2_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    buckboost2_init( &buckboost2, &cfg );

    buckboost2_power_on( &buckboost2 );
    buckboost2_set_mode( &buckboost2, BUCKBOOST2_WITH_IMPROVEMENT );
}

void application_task ( void )
{
    //  Task implementation.

}

int main ( void ) 
{
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif
    
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}


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