Unlock the full potential of any battery with SPV1050 and PIC18LF4550

Embrace the future of battery charging

Published Nov 01, 2023

Click board™

Peltier Click

Dev. board

EasyPIC v7

Compiler

NECTO Studio

MCU

PIC18LF4550

Charge any battery type, including lithium-based, solid-state thin film and super-capacitor

Hardware Overview

How does it work?

Peltier Click is based on the SPV1050, an ultralow power energy harvester and battery charger from STMicroelectronics that can charge lithium-based batteries. A thermoelectric harvester produces green energy for energy harvesting with many advantages: maintenance-free because of the use of a highly reliable and compact solid-state device; silent and quiet; highly efficient in environmental terms because the heat is harvested from waste heat sources and converted into electricity. Because of this feature, the Peltier click can be used for various applications such as WSN, HVAC, building and home automation, industrial control, remote metering, lighting, security, surveillance, and wearable and biomedical sensors. The SPV1050 is an ultralow power and high-efficiency energy harvester and battery charger, which implements the MPPT function and integrates the switching elements of a buck-boost converter. The SPV1050 device allows the charge of a lithium

battery by tightly monitoring the end-of-charge and the minimum battery voltage to avoid over-discharge and preserve the battery life. The power manager is suitable for TEG harvesting sources, as it covers the input voltage range from 75 mV up to 18 V and guarantees high efficiency in both buck-boost and boost configurations. Furthermore, the SPV1050 device shows very high flexibility thanks to the trimming capability of the end-of-charge and undervoltage protection voltages. In such a way, any source and battery are matched. The MPPT is programmable by a resistor input divider and allows maximizing the source power under any temperature and irradiance condition. Some of the key features of the SPV1050 are its transformerless thermoelectric generators and PV modules energy harvester, high efficiency for any harvesting source, and up to 70 mA maximum battery charging current. It is a fully integrated buck-boost DC-DC converter with a

programmable MPPT by external resistors, 2.6 V to 5.3 V trimmable battery charge voltage level (± 1% accuracy), 2.2 V to 3.6 V trimmable battery discharge voltage level (± 1% accuracy) with two fully independent LDOs (1.8 V and 3.3 V output). The SPV1050 can turn LDO control pins on/off, and it has a battery disconnect function for battery protection while the battery is connected and ongoing charge logic open drain indication pins. The SPV1050 is an ultralow power energy harvester with an embedded MPPT algorithm, a battery charger, and a power manager designed for applications up to 400 mW. This Click board™ can only be operated with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used as a reference for further development.

Features overview

Development board

EasyPIC v7 is the seventh generation of PIC development boards specially designed to develop embedded applications rapidly. It supports a wide range of 8-bit PIC microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB-B. 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 v7 allows you to connect accessory boards, sensors, and custom electronics more efficiently than ever. Each part of

the EasyPIC v7 development board contains the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block 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-B (USB-B) 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 v7 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

You complete me!

Accessories

Li-Polymer Battery is the ideal solution for devices that demand a dependable and long-lasting power supply while emphasizing mobility. Its compatibility with mikromedia boards ensures easy integration without additional modifications. With a voltage output of 3.7V, the battery meets the standard requirements of many electronic devices. Additionally, boasting a capacity of 2000mAh, it can store a substantial amount of energy, providing sustained power for extended periods. This feature minimizes the need for frequent recharging or replacement. Overall, the Li-Polymer Battery is a reliable and autonomous power source, ideally suited for devices requiring a stable and enduring energy solution. You can find a more extensive choice of Li-Polymer batteries in our offer.

Used MCU Pins

mikroBUS™ mapper

Enable 3.3V LDO

RE1

RST

Enable 1.8V LDO

RE0

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

Chare Indicator

RC0

PWM

Battery Connection Indicator

RB0

INT

SCL

SDA

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

EasyPIC v7 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v7 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 v7 Access MB 1 - 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 Peltier Click driver.

Key functions:

peltier_enable_ldo2 - Enables LDO2 function
peltier_disable_ldo2 - Disables LDO2 function
peltier_battery_charge - Check ongoing battery charge flag pin 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 
 * \brief Peltier Click example
 * 
 * # Description
 * This application is ultralow power energy harvester and battery charger.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes GPIO driver, disables both 1.8V and 3.3V outputs and starts write log.
 * 
 * ## Application Task  
 * This example demonstrates the use of Peltier Click board by first enableing 1.8V output, second 
   by enableing 3.3V output, then enabling both outputs and finally disabling both outputs in 5 seconds intervals.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "peltier.h"

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

static peltier_t peltier;
static log_t logger;

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    peltier_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.

    peltier_cfg_setup( &cfg );
    PELTIER_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    peltier_init( &peltier, &cfg );
}

void application_task ( void )
{
    log_printf( &logger, "   1.8V output    \r\n" );
    log_printf( &logger, "------------------\r\n" );
    peltier_enable_ldo1( &peltier );
    peltier_disable_ldo2( &peltier );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    
    log_printf( &logger, "   3.3V output    \r\n" );
    log_printf( &logger, "------------------\r\n" );
    peltier_disable_ldo1( &peltier );
    peltier_enable_ldo2( &peltier );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    
    log_printf( &logger, "   Both outputs   \r\n" );
    log_printf( &logger, "------------------\r\n" );
    peltier_enable_ldo1( &peltier );
    peltier_enable_ldo2( &peltier );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    
    log_printf( &logger, " Disable  outputs \r\n" );
    log_printf( &logger, "------------------\r\n" );
    peltier_disable_ldo1( &peltier );
    peltier_disable_ldo2( &peltier );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
}

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