Upgrade your power needs with triple step-down conversion based on TPS65263 and ATmega644P
Buck it right, save power
Published Jul 31, 2023
Click board™
3xBuck click
Dev Board
EasyAVR v7
Compiler
NECTO Studio
MCU
ATmega644P
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
EasyAVR v7 is the seventh generation of AVR development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 16-bit AVR microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB. 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, EasyAVR v7 allows you to connect accessory boards, sensors, and custom electronics more
efficiently than ever. Each part of the EasyAVR 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 a wide range of external power sources, including an external 12V power supply, 7-12V AC or 9-15V 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 which cover a wide range of 16-bit AVR MCUs. EasyAVR 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
AVR
MCU Memory (KB)
64
Silicon Vendor
Microchip
Pin count
40
RAM (Bytes)
4096
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 EasyAVR v7 as your development board.
Track your results in real time
Application Output via UART Mode
1. Once the code example is loaded, pressing the "FLASH" button initiates the build process, and programs it on the created setup.
2. After the programming is completed, click on the Tools icon in the upper-right panel, and select the UART Terminal.
3. After opening the UART Terminal tab, first check the baud rate setting in the Options menu (default is 115200). If this parameter is correct, activate the terminal by clicking the "CONNECT" button.
4. Now terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.
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
