Intermediate
30 min
0

Personalize your energy management with LMR36015 and PIC18F86J55

Voltage control at its finest

Buck 11 Click with UNI-DS v8

Published Aug 01, 2023

Click board™

Buck 11 Click

Development board

UNI-DS v8

Compiler

NECTO Studio

MCU

PIC18F86J55

Achieve stable and regulated output voltage that matches the specific requirements of electronic devices

A

A

Hardware Overview

How does it work?

Buck 11 Click is based on the LMR36015, a synchronous step-down converter from Texas Instruments. This advanced integrated step-down converter requires a minimum number of external components readily available on the market. It utilizes a peak-current-mode control architecture, which ensures good efficiency and automatic PFM/PWM mode switching. The LMR36015 buck converter features over-current, under-voltage, and thermal protection, making Buck 11 click a robust and reliable power supply solution. The feedback voltage on the FB pin determines the output voltage. The output voltage is set to 3.3V, making it usable with most embedded applications, allowing them to be powered from the same source, like the rest of the application, which may use a higher voltage for its operation. This is a common-case scenario in various field applications requiring a relatively high voltage, i.e.,

for servos, step motors, displays, and more. When there is an overload at the output, the low-side MOSFET will allow the inductor current to drop. It will remain open until the current through the inductor falls below the limit. If the FB voltage drops too much during the overload, the device enters the hiccup mode, in which the device attempts to periodically restarts itself. The LMR36015 can automatically switch between PWM and PFM modes, depending on the current through the load. At very light loads, the device is operated in PFM mode. In this mode, the high-side MOSFET is operated in bursts, after which the LMR36015 waits for the current through the inductor to drop below the limit. This way, the device is idle while the light load consumes energy stored within the coil. This greatly improves the efficiency when a light load is used. While operated in PWM mode, the output MOSFETs

are driven with the constant PWM frequency of 400kHz, using the pulse width modulation to control the output voltage. This provides good voltage regulation and a low output voltage ripple. Featuring the HotRod™ technology, the LMR36015 occupies a small area on the PCB. Combined with the low count of external components it requires, the LMR36015 leaves enough space for an additional IC to be used. This click uses the MCP3221, a 12-bit A/D converter (ADC) that uses the I2C interface from Microchip. It allows monitoring of the output voltage over the I2C interface. This ADC is powered by the +5V mikroBUS™ power rail. The same voltage is used as a reference. 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.

Buck 11 Click hardware overview image

Features overview

Development board

UNI-DS 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 STM32, Kinetis, TIVA, CEC, MSP, PIC, dsPIC, PIC32, and AVR MCUs 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, UNI-DS v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the UNI-DS 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. UNI-DS 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.

UNI-DS v8 horizontal image

Microcontroller Overview

MCU Card / MCU

default

Type

8th Generation

Architecture

PIC

MCU Memory (KB)

96

Silicon Vendor

Microchip

Pin count

80

RAM (Bytes)

3904

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
NC
NC
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PC3
SCL
I2C Data
PC4
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

Buck 11 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 UNI-DS 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 Buck 11 Click driver.

Key functions:

  • buck11_read_adc - ADC Read function

  • buck11_get_vout - Get VOUT function

  • buck11_get_averaged_vout - Get averaged VOUT function

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 
 * \brief Buck11 Click example
 * 
 * # Description
 * This aplication control voltage using Buck 11.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes I2C serial interface and selects the desired VDD voltage value
 * and VOUT value resolution (to get VOUT value in Volts).
 * 
 * ## Application Task  
 * Reads the averaged VOUT voltage calculated to Volts by performing a 30 conversions
 * in one measurement cycle. The measured results will be showed on the uart terminal every 300 milliseconds.
 * 
 * *note:* 
 * The user should measure the VDD voltage value and enter this measured value to the function as VDD value to get
 * more accurate measurement. This VDD voltage is used as reference voltage for the AD conversion.
 * 
 * The input voltage (VIN) range is from 4.2V to 60V.
 * The output current (IOUT) value should not be greater than 1.5A.
 *
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "buck11.h"

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

static buck11_t buck11;
static log_t logger;

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

void application_init ( void )
{
    uint8_t vout_resol;
    log_cfg_t log_cfg;
    buck11_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.

    buck11_cfg_setup( &cfg );
    BUCK11_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    buck11_init( &buck11, &cfg );

    Delay_ms( 500 );
    
    buck11_set_vdd_value( 4.935 );
    vout_resol = BUCK11_VOUT_VOLTS;
    
    log_printf( &logger, "** Buck 11 is initialized ** \r\n" );
    log_printf( &logger, "************************************* \r\n" );
    Delay_ms( 200 );
}

void application_task ( )
{
    float vout_value;
    uint8_t vout_resol;

    vout_value = buck11_get_averaged_vout( &buck11, vout_resol, 30 );

    log_printf( &logger, "VOUT: %f", vout_value );
    
    if ( vout_resol == BUCK11_VOUT_VOLTS )
    {
        log_printf( &logger, " V \r\n" );
    }
    else
    {
        log_printf( &logger, " mV \r\n" );
    }
    
    log_printf( &logger, "************************************* \r\n" );
    Delay_ms( 300 );
}

void main ( void )
{
    application_init( );

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


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

Additional Support

Resources