Upgrade your power needs with triple step-down conversion based on TPS65263 and PIC18F47K42TQFP
Buck it right, save power
Published Feb 13, 2024
Click board™
3xBuck click
Dev Board
Curiosity Nano with PIC18F47K42
Compiler
NECTO Studio
MCU
PIC18F47K42TQFP
Offering voltage control at your fingertips, this cutting-edge solution empowers your gadgets to perform at their best
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Hardware Overview
How does it work?
3xBuck Click is based on the TPS65263, a triple synchronous step-down converter from Texas Instruments with programmable dynamic voltage scaling. This IC contains three independent switching sections, which operate at a fixed frequency of 600kHz. One buck section uses the switching clock, which is 180˚ out-of-phase, with respect to the other two sections. This ensures low input current ripple, as well as the lowered EMI of the power supply itself. The TPS65263 IC has the I2C bus logic section, which allows the output voltage of each converter to be programmed. The output voltage is initially set with feedback voltage divider resistors on each section. The output voltages of the sections are set to 5V, 3.3V, and 1.8V because these values are the most commonly used in embedded applications. As soon as the command is sent via the I2C interface, the logic section of the TPS65263 IC takes over the control, allowing to program the voltage at each of the three outputs between 0.68V to 1.95V, with 10mV steps. This allows the desired output to be fine-tuned according to the application's specific needs, which is powered by the 3xBuck click. The I2C interface is also used to independently retrieve
the Power Good status, the overcurrent, and the die temperature warning for each buck section. There are three completely independent switching sections in the TPS65263 IC, meaning each has its dedicated Enable pin, Soft-Start pin, and loop compensation pin. The Enable pins for each section are routed to mikroBUS™. EN1, EN2, and EN3 are routed to AN, PWM, and INT pins of the mikroBUS™, respectively. This allows the host MCU to control the operation of the 3xBuck Click. Not all three sections share the same characteristics. The output of the 3xBuck click labeled as 1V8 (VOUT1) can withstand up to 3A of current while supplied with 12V across the input terminal. The other two outputs can deliver up to 2A, keeping the output well regulated, well within the 1% margin. However, it should be noted that this is the combined current rating, so if multiple outputs are used, the summed current consumption should not exceed these values. The input voltage should range between 4.5V and 18V, with a remark that it must be sufficiently higher than the selected output voltage to reach the specified voltage and current ratings. The soft-start feature uses a 10nF capacitor at the
dedicated SS pin. Each channel has its own dedicated SS pin, so three pins are used to set the soft start of each channel. The soft-start function prevents the high inrush current on power up, ramping up the output current during the soft-start period, defined by the capacitor. As mentioned, the device features protection functions that allow reliable operation in events such as short circuit protection, overcurrent, overvoltage, and thermal protection. If the connected load draws too much current, the cycle-by-cycle current limit will be activated on both high- and low-side output MOSFETs. If the high current condition persists after 0.5ms, the device will enter the hiccup mode, shutting down completely, then restarting after 14ms. The whole startup sequence will be repeated; if the fault condition persists on the output, this cycle will be repeated. This prevents damage in the case of significant loads connected at the output. The logic voltage level of the 3xBuck click can be selected by switching the SMD jumper labeled VCC SEL to an appropriate position. This allows interfacing with both 3.3V and 5V MCUs, expanding the interfacing options of this board.
Features overview
Development board
PIC18F47K42 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate the PIC18F47K42 microcontroller (MCU). Central to its design is the inclusion of the powerful PIC18F47K42 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 2.3V to 5.1V (limited by USB input voltage), with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.
Microcontroller Overview
MCU Card / MCU
Architecture
PIC
MCU Memory (KB)
128
Silicon Vendor
Microchip
Pin count
40
RAM (Bytes)
8192
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
Take a closer look
Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Curiosity Nano with PIC18F47K42 as your development board.
Track your results in real time
Application Output
After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.
After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.
Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.
Software Support
Library Description
This library contains API for 3xBuck Click driver.
Key functions:
c3xbuck_enable_buck- This function enables desired Buck on the boardc3xbuck_disable_buck- This function disables desired Buck on the boardc3xbuck_set_voltage- This function sets voltage on desired Buck on the board
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 3xBuck Click example
*
* # Description
* This example demonstrates the use of the 3 x Buck Click Board.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and performs the click default configuration.
*
* ## Application Task
* Alternates between predefined and default values for the Bucks output and
* logs the current set values on the USB UART.
*
* @note
* The default output voltage on Buck 1 is 1800mV, Buck 2 is 3300mV, and Buck 3 is 5000mV.
* Configurable output voltage on all Bucks ranges from 680mV to 1950mV.
*
* \author Petar Suknjaja
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "c3xbuck.h"
// ------------------------------------------------------------------ VARIABLES
static c3xbuck_t c3xbuck;
static log_t logger;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
c3xbuck_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.
c3xbuck_cfg_setup( &cfg );
C3XBUCK_MAP_MIKROBUS( cfg, MIKROBUS_1 );
c3xbuck_init( &c3xbuck, &cfg );
Delay_ms ( 100 );
c3xbuck_default_cfg ( &c3xbuck );
log_info( &logger, "---- Application Task ----" );
}
void application_task ( void )
{
// Task implementation.
log_printf( &logger, "Setting predefined values : \r\n" );
log_printf( &logger, "Buck 1 : 1000 mV\r\n");
log_printf( &logger, "Buck 2 : 1250 mV\r\n");
log_printf( &logger, "Buck 3 : 1500 mV\r\n");
c3xbuck_set_voltage( &c3xbuck, C3XBUCK_SELECT_BUCK_1, C3XBUCK_OUTPUT_VOLTAGE_1000mV );
c3xbuck_set_voltage( &c3xbuck, C3XBUCK_SELECT_BUCK_2, C3XBUCK_OUTPUT_VOLTAGE_1250mV );
c3xbuck_set_voltage( &c3xbuck, C3XBUCK_SELECT_BUCK_3, C3XBUCK_OUTPUT_VOLTAGE_1500mV );
// 10 seconds delay
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
log_printf( &logger, "Setting default values: \r\n");
log_printf( &logger, "Buck 1 : 1800 mV\r\n");
log_printf( &logger, "Buck 2 : 3300 mV\r\n");
log_printf( &logger, "Buck 3 : 5000 mV\r\n");
c3xbuck_set_voltage( &c3xbuck, C3XBUCK_SELECT_BUCK_1, C3XBUCK_BUCK_DEFAULT_OUTPUT_VOLTAGE );
c3xbuck_set_voltage( &c3xbuck, C3XBUCK_SELECT_BUCK_2, C3XBUCK_BUCK_DEFAULT_OUTPUT_VOLTAGE );
c3xbuck_set_voltage( &c3xbuck, C3XBUCK_SELECT_BUCK_3, C3XBUCK_BUCK_DEFAULT_OUTPUT_VOLTAGE );
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
