Texas Instruments TPA005D12 Overview of Class-D Audio Amplifiers, ±5. Class-D Functional Diagram

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The TPA005D12 Class-D Audio Power Amplifier Evaluation Module

3.2.2Overview of Class-D Audio Amplifiers

Class-D audio amplifiers are very similar in operation to switch-mode power supplies in that both compare an input signal with a reference to create an error voltage that controls a pulse-width modulator (PWM) circuit. The PWM circuit then produces an output signal at constant frequency and with a duty cycle that varies according to the input signal. A block diagram of the major components that make up the amplifier is shown in Figure 3±5.

Figure 3±5. Class-D Functional Diagram

Audio

Analog

Source

Ramp

Generator

VIN

VRAMP

VERROR

PWM

VCONTROL

Comparator

Control

H-Bridge

 

 

 

 

VOUT

 

LPF

Load

The audio input signal (VIN) is applied to a very fast comparator along with a

ramp signal (VRAMP) created by the ramp generator. Each time the triangle wave from the ramp generator crosses the audio input signal level, the

comparator sends an error signal (VERROR) to the PWM control circuit. The PWM control signal (VCONTROL) then regulates the duty cycle of the high-current DMOS power transistors of the H-bridge, providing the output

signal (VOUT).

These transistors operate in either the cutoff or saturated regions, rather than the linear region, which is where class AB amplifiers operate. This reduces switching and conduction losses, reducing the power dissipated by the power transistors and allowing more power to be delivered to the load. An inductor-capacitor (LC) low-pass filter (LPF) then removes the high frequency switching component from VOUT, leaving an amplified version of the original input signal. Examples of these waveforms are shown in Figure 3±6.

3-6

Details

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Contents Users Guide Important Notice Preface Related Documentation From Texas InstrumentsPage Contents Figures TablesIntroduction Feature Highlights Description Typical TPA005D12 Class-D EVM SpecificationsMaximum Quick Start OFFPrecautions Audio PowerQuick Start List for Platform Platform PreparationsQuick Start List for Stand-Alone Details ±1. The TI Plug-N-Play Audio Amplifier Evaluation Platform TPA005D12 Class-D Audio Power Amplifier Evaluation Module TP9 GND VDD2 1 TPA005D12 Class-D Stereo Audio Amplifier IC TP3±5. Class-D Functional Diagram Overview of Class-D Audio Amplifiers±6. Class-D Input and Output Waveforms Bridge-Tied Load BTL OperationControl and Indicator Circuits Class-D Differential Inputs6 TPA005D12 Class-D EVM Test Points ±2. TPA005D12 Class-D EVM Test PointsClass-D Amplifier Design Considerations EVM Removal Installing and Removing EVM BoardsEVM Insertion 2.1 S1 Ð Shutdown Module Switches2.2 S2 Ð Mute Switch Headphone Output Jack Signal RoutingSignal Conditioning Headphone Jack Control Signals ShutdownMute/Mode Select JP6 Mute/Mode Polarity Select JP8Power Requirements JP1 JP2 JP3 JP4 JP5 JP6 JP7 JP8Outputs Inputs and OutputsInputs Monitor Output Connections Controls and IndicatorsInput Connections TPA005D12 Class-D EVM Performance Characteristics ±11. Class-D Amplifier Frequency Response at 4 Ω±12. Class-D Amplifier Distortion versus Output Power at 4 Ω ± % Crosstalk Frequency TPA005D12 Class-D EVM Interconnects TPA005D12 Class-D EVM Bill of Materials ±5. TPA005D12 Class-D EVM Bill of MaterialsTPA005D12 Class-D EVM Schematic ±18. TPA005D12 Class-D EVM Schematic Diagram±19. TPA005D12 Class-D EVM Top Assembly 10 TPA005D12 Class-D EVM PCB Layers±21. TPA005D12 Class-D EVM Top Layer ±23. TPA005D12 Class-D EVM Third Layer Details

TPA005D12 specifications

The Texas Instruments TPA005D12 is a highly regarded digital audio power amplifier that is engineered for high-performance applications. It is part of TI's TPA series, which is known for its efficient power delivery and superior sound quality. The TPA005D12 is designed to drive passive speakers while ensuring minimal power loss and efficient heat management.

One of the standout features of the TPA005D12 is its ability to provide 5 watts of continuous output power per channel into an 8-ohm load with a low total harmonic distortion (THD) rating. This makes it suitable for use in a variety of audio applications, including computer speakers, soundbars, and portable audio systems. The amplifier operates from a single supply voltage, ranging typically from 4.5V to 14V, allowing for flexible integration into different power supply environments.

The TPA005D12 adopts Class-D amplification technology, which significantly enhances power efficiency compared to traditional linear amplifiers. Class-D amplifiers convert the input audio signal into a series of pulse-width modulated signals, resulting in increased power savings and reduced heat generation. This not only improves the overall energy efficiency but also contributes to a longer operational lifespan for devices utilizing this technology.

Additionally, the TPA005D12 features an integrated thermal and short-circuit protection mechanism, which helps safeguard the amplifier from potential damage due to excessive temperatures or electrical faults. This reliability factor is crucial for manufacturers looking to create robust consumer electronics.

Another important characteristic is its integrated low-noise power supply rejection ratio (PSRR), which helps maintain sound clarity and reduces the impact of power supply noise on audio quality. The TPA005D12 also supports differential input signals, which can improve common-mode noise rejection and further enhance audio performance.

The device is offered in a compact package suitable for space-constrained applications, enabling easy integration into various designs. With a combination of low cost, high efficiency, and excellent audio performance, the Texas Instruments TPA005D12 stands out as a top choice for developers and engineers seeking reliable audio amplification solutions. Whether in home entertainment systems or personal audio devices, the TPA005D12 is designed to deliver exceptional sound quality with a minimal footprint.