Make your music pop with TPA3138D2 and STM32F031K6
Amplify your groove - because your beats deserve to roar!
Published Oct 01, 2024
Click board™
AudioAmp 5 Click
Dev Board
Nucleo 32 with STM32F031K6 MCU
Compiler
NECTO Studio
MCU
STM32F031K6
Upgrade your audio setup and unleash the full potential of your speakers with our high-quality amplifier, designed to deliver powerful, clean, and distortion-free sound
A
A
Hardware Overview
How does it work?
AudioAmp 5 Click is based on the TPA3138D2, an inductor-less stereo class-D audio amplifier from Texas Instruments. It has many features that make this IC an attractive solution for battery-powered and stand-alone active speakers. It is very flexible regarding the PSU voltage: it can work with voltages within the range of 3.5V to 14.4V. With only 3.5V at the PSU connector, it can still deliver 1W of power to a 6Ω load (per channel). However, its nominal operating voltage is 12V, reaching up to 10W of power to the connected 6Ω speaker, with only 1% of Total Harmonic Distortion (THD). The TPA3138D2 IC features a set of protections, including output short circuit, over-temperature, under-voltage, and over-voltage protection. These protections will be reported at the SD/FAULT (EN) I/O pin if any of these protections are activated. The TPA3138D2 IC can also detect a constant DC current at the output. When a DC detection event occurs, the outputs are turned OFF, protecting the connected speakers. Very often, a DC detection event can be triggered when the circuit is powered up, so it is advisable to hold the EN pin to a LOW logic level for a short period, preventing faulty DC detection reports and loud pops. The output stage of the TPA3138D2 operates in Bridge-Tied Load (BTL) topology. This means there are two outputs per channel: inverted and non-inverted (OUTN and OUTP). Class-D amplifier produces the sound by modulating the pulse-with of the output voltage. It offers a choice of two PWM modulation schemes,
selectable by the MODE_SEL pin of the IC. This pin is routed to the mikroBUS™ RST pin, labeled as MDS on this Click board™. By default, a resistor pulls the MDS pin to a LOW logic level. When the MDS pin is set to a LOW logic level, the TPA3138D2 uses the BD Modulation scheme. This scheme reduces the need for a typical LC reconstruction filter at the output. While there is no input, both OUTN and OUTP are in phase, with a 50% duty cycle. There is no current through the speaker in this case. The duty cycle will increase at the OUTP and decrease at the OUTN simultaneously when the positive half-phase of the audio signal is applied at the input. For the negative half-phase at the input, the opposite will happen. The greater the difference in pulse width, the greater the current through the connected speaker. When the MDS pin is set to a HIGH logic level, the TPA3138D2 uses the 1SPW Modulation scheme. This scheme allows low idle current and better overall efficiency at the expense of increased THD. Both OUTP and OUTN are held in phase at about 15% duty cycle. As the input signal is applied, one output is driven to the GND while the other output increases. The modulation takes place through this single output, reducing the switching losses. Again, the positive half-phase will cause the OUTN to be driven to GND, while the negative half-phase of the input signal causes the OUTP to be driven to GND. The SD/FAULT pin allows the host MCU to enable/disable outputs. Pulling this pin to a
LOW logic level makes the outputs muted, and the TPA3138D2 IC enters the low-current state, reducing the supply current to the absolute minimum level. Muting the TPA3138D2 before cutting down the power supply reduces the pops and clicks that might appear in this case. The SD/FAULT pin is routed to the mikroBUS™ CS pin labeled EN on this Click board™, and a resistor pulls it to a HIGH logic level. There is a selectable input gain on Audio Amp 5 click. Applying a LOW logic level to the GAIN_SEL pin sets the input gain to 20dB. A HIGH logic level sets the input gain to 26dB. This allows matching the input signal to reach the optimal output level. This pin is routed to the mikroBUS™ PWM pin labeled as GS and pulled to the LOW logic level by a resistor. The external PSU should be connected to the VIN terminal. A line-level audio source can be connected to the LINE IN 3.5mm jack stereo connector, while the speakers should be connected to the angled spring terminals labeled OUTL and OUTR. These terminals have their polarities marked on the top overlay. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development.
Features overview
Development board
Nucleo 32 with STM32F031K6 MCU board provides an affordable and flexible platform for experimenting with STM32 microcontrollers in 32-pin packages. Featuring Arduino™ Nano connectivity, it allows easy expansion with specialized shields, while being mbed-enabled for seamless integration with online resources. The
board includes an on-board ST-LINK/V2-1 debugger/programmer, supporting USB reenumeration with three interfaces: Virtual Com port, mass storage, and debug port. It offers a flexible power supply through either USB VBUS or an external source. Additionally, it includes three LEDs (LD1 for USB communication, LD2 for power,
and LD3 as a user LED) and a reset push button. The STM32 Nucleo-32 board is supported by various Integrated Development Environments (IDEs) such as IAR™, Keil®, and GCC-based IDEs like AC6 SW4STM32, making it a versatile tool for developers.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M0
MCU Memory (KB)
32
Silicon Vendor
STMicroelectronics
Pin count
32
RAM (Bytes)
4096
You complete me!
Accessories
Click Shield for Nucleo-32 is the perfect way to expand your development board's functionalities with STM32 Nucleo-32 pinout. The Click Shield for Nucleo-32 provides two mikroBUS™ sockets to add any functionality from our ever-growing range of Click boards™. We are fully stocked with everything, from sensors and WiFi transceivers to motor control and audio amplifiers. The Click Shield for Nucleo-32 is compatible with the STM32 Nucleo-32 board, providing an affordable and flexible way for users to try out new ideas and quickly create prototypes with any STM32 microcontrollers, choosing from the various combinations of performance, power consumption, and features. The STM32 Nucleo-32 boards do not require any separate probe as they integrate the ST-LINK/V2-1 debugger/programmer and come with the STM32 comprehensive software HAL library and various packaged software examples. This development platform provides users with an effortless and common way to combine the STM32 Nucleo-32 footprint compatible board with their favorite Click boards™ in their upcoming projects.
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Nucleo 32 with STM32F031K6 MCU as your development board.
Track your results in real time
Application Output via Debug Mode
1. Once the code example is loaded, pressing the "DEBUG" button initiates the build process, programs it on the created setup, and enters Debug mode.
2. After the programming is completed, a header with buttons for various actions within the IDE becomes visible. Clicking the green "PLAY" button starts reading the results achieved with the Click board™. The achieved results are displayed in the Application Output tab.
Software Support
Library Description
This library contains API for AudioAmp 5 Click driver.
Key functions:
audioamp5_mode_select- This function puts a device to the desired mode.audioamp5_gain_select- This function performs a desired gain selection.eaudioamp5_config_update- This function to update the configuration of the module.
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 Audio Amp 5 Click example
*
* # Description
* This example consist of sending special commands for audio output control,
* selecting different output modes and turning on/off the audio output.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes GPIO interface on the desired mikrobus selection,
* and performs a device init configuration.
*
* ## Application Task
* Checks the entered command and, if the command is valid,
* performs a device configuration which the entered command determines.
*
*
* \author Petar Suknjaja
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "audioamp5.h"
// ------------------------------------------------------------------ VARIABLES
static audioamp5_t audioamp5;
static log_t logger;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
audioamp5_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.
audioamp5_cfg_setup( &cfg );
AUDIOAMP5_MAP_MIKROBUS( cfg, MIKROBUS_1 );
audioamp5_init( &audioamp5, &cfg );
audioamp5_default_cfg( &audioamp5 );
log_printf( &logger, "** Audio Amp 5 is initialized **\r\n" );
Delay_ms( 500 );
}
void application_task ( void )
{
// Task implementation.
audioamp5_gain_select( &audioamp5, AUDIOAMP5_GAIN_26DB );
audioamp5_config_update( &audioamp5 );
log_printf( &logger, "** Gain value is 26dB **\r\n" );
Delay_ms ( 5000 );
audioamp5_gain_select( &audioamp5, AUDIOAMP5_GAIN_20DB );
audioamp5_config_update( &audioamp5 );
log_printf( &logger, "** Gain value is 20dB **\r\n" );
Delay_ms ( 5000 );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
