Experience next-gen power management with MAX17504 and ATmega328P
Buck the voltage, embrace the efficiency
Published Feb 14, 2024
Click board™
BUCK 7 Click
Dev Board
Arduino UNO Rev3
Compiler
NECTO Studio
MCU
ATmega328P
Don't compromise on voltage stability. Choose this voltage step-down solution, and regulate from 5V up to 35V!
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Hardware Overview
How does it work?
Buck 7 Click is based on the MAX17504, a high-efficiency, synchronous step-down DC-DC converter with internal compensation from Analog Devices. This advanced integrated step-down converter requires a minimum number of external components, thanks to the internal feedback loop compensation. It utilizes a peak-current-mode control architecture, meaning that while the high side MOSFET is open and the current through the inductor ramps up, an overcurrent event will cause the MOSFET to close, preventing this current from becoming dangerously high. If there is a short circuit condition on the output, the device will reattempt to start after a timeout period, and if the condition is still present at the output, it will be turned off for another timeout period. The MCP4921, a 12-bit D/A converter with SPI Interface made by Microchip, is used on the feedback loop to allow adjustment of the output voltage via the SPI interface. This DAC affects the current through the feedback loop forcing the PWM duty cycle of the internal generator, regulating the output voltage to a programmed value that way. As a result, sending a digital value through the SPI interface to the MCP4921 makes it possible to control the output
voltage level in the range from 3.3V to 90% of the input voltage value. While operating normally (PWM mode), the high and the low side MOSFETs are switched synchronously with the signal from the internal PWM generator, causing the current through the inductor to ramp up and down, regulating the output voltage that way. The PWM signal's lower pulse width (duty cycle) results in a lower voltage at the output. Besides PWM mode, the device can also operate in the PFM mode (Pulse Frequency Modulation). This mode allows even higher efficiency for light loads, as the low-side MOSFET is completely unused. The high side MOSFET charges the inductor, letting the load drain it. During this period, the IC is in a hibernation state. This mode results in slightly more ripple at the output, with the added benefit of high efficiency for light loads. It is perfectly suited to power devices in the low power consumption mode (Sleep, Standby, and more). The DCM mode is the compromise mode between the PWM and PFM modes. The low-side MOSFET is still unused for light loads, but the PWM pulses are not skipped, and the IC constantly drives the high-side MOSFET. This mode produces ripple at the output, but it is slightly less efficient than
the PFM mode for light loads. The MODE pin selects different modes. This pin is routed to the mikroBUS™ PWM pin (labeled as MOD), allowing the MCU to control the mode. When set to a HIGH level, the IC works in the DCM mode for light loads. When left floating, the PFM mode is selected. When it is set to the LOW logic level, the constant frequency PWM mode is set. The #RES pin of the IC is routed to the mikroBUS™ RST pin. This pin signalizes problems with the output voltage. The pin is driven to a LOW logic level when the output voltage drops under 92% of the nominal value or during the thermal shutdown. It is an open drain output, otherwise pulled to a HIGH logic level (when not asserted). To enable the buck converter IC, a HIGH logic level needs to be present at the EN pin of the IC, routed to the mikroBUS™ AN pin (labeled as EN). This allows the MCU to control the Power ON function of the Click board™ effectively. When the IC is enabled, the LED indicator labeled EN indicates that the IC is activated and the step-down conversion is in progress. The soft-start circuit prevents high inrush currents by ramping up the output voltage from 0V to the nominal value.
Features overview
Development board
Arduino UNO is a versatile microcontroller board built around the ATmega328P chip. It offers extensive connectivity options for various projects, featuring 14 digital input/output pins, six of which are PWM-capable, along with six analog inputs. Its core components include a 16MHz ceramic resonator, a USB connection, a power jack, an
ICSP header, and a reset button, providing everything necessary to power and program the board. The Uno is ready to go, whether connected to a computer via USB or powered by an AC-to-DC adapter or battery. As the first USB Arduino board, it serves as the benchmark for the Arduino platform, with "Uno" symbolizing its status as the
first in a series. This name choice, meaning "one" in Italian, commemorates the launch of Arduino Software (IDE) 1.0. Initially introduced alongside version 1.0 of the Arduino Software (IDE), the Uno has since become the foundational model for subsequent Arduino releases, embodying the platform's evolution.
Microcontroller Overview
MCU Card / MCU
Architecture
AVR
MCU Memory (KB)
32
Silicon Vendor
Microchip
Pin count
28
RAM (Bytes)
2048
You complete me!
Accessories
Click Shield for Arduino UNO has two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the Arduino UNO board without effort. The Arduino Uno, a microcontroller board based on the ATmega328P, provides an affordable and flexible way for users to try out new concepts and build prototypes with the ATmega328P microcontroller from various combinations of performance, power consumption, and features. The Arduino Uno has 14 digital input/output pins (of which six can be used as PWM outputs), six analog inputs, a 16 MHz ceramic resonator (CSTCE16M0V53-R0), a USB connection, a power jack, an ICSP header, and reset button. Most of the ATmega328P microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the Arduino UNO board with our Click Shield for Arduino UNO, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.
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 Arduino UNO Rev3 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 Buck 7 Click driver.
Key functions:
buck7_set_output_voltage- Function for settings output voltagebuck7_enable- Function for enable chipbuck7_set_mode- Function for settings chip mode
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 BUCK7 Click example
*
* # Description
* This demo application controls the voltage at the output using the BUCK 7 click.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes Driver init, reset chip, enable chip and set mode
*
* ## Application Task
* Sets output voltage to 5V, 10V, 15V, 20V, 25V every 3 seconds.
* It is necessary to set the input voltage on 2.7V + maximum output voltage.
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "buck7.h"
// ------------------------------------------------------------------ VARIABLES
static buck7_t buck7;
static log_t logger;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
buck7_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.
buck7_cfg_setup( &cfg );
BUCK7_MAP_MIKROBUS( cfg, MIKROBUS_1 );
buck7_init( &buck7, &cfg );
buck7_enable( &buck7 );
buck7_set_mode( &buck7, BUCK7_MODE_PWM );
}
void application_task ( )
{
buck7_set_output_voltage( &buck7, BUCK7_OUT_VOLTAGE_5V );
Delay_ms( 3000 );
buck7_set_output_voltage( &buck7, BUCK7_OUT_VOLTAGE_10V );
Delay_ms( 3000 );
buck7_set_output_voltage( &buck7, BUCK7_OUT_VOLTAGE_15V );
Delay_ms( 3000 );
buck7_set_output_voltage( &buck7, BUCK7_OUT_VOLTAGE_20V );
Delay_ms( 3000 );
buck7_set_output_voltage( &buck7, BUCK7_OUT_VOLTAGE_25V );
Delay_ms( 3000 );
buck7_set_output_voltage( &buck7, BUCK7_OUT_VOLTAGE_20V );
Delay_ms( 3000 );
buck7_set_output_voltage( &buck7, BUCK7_OUT_VOLTAGE_15V );
Delay_ms( 3000 );
buck7_set_output_voltage( &buck7, 0x0BB8 );
Delay_ms( 3000 );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
