The TPA005D12 Class-D Audio Power Amplifier Evaluation Module

Figure 3±6. Class-D Input and Output Waveforms

VIN

VRAMP

VDD

VOUT

0 V

The VRAMP signal must be at a much higher frequency than the highest frequency component of VIN to obtain an accurate representation at the

low-pass filter output and allow greater attenuation of the switching

component of VOUT. The TPA005D12 class-D EVM uses a 250 kHz VRAMP signal to sample VIN. This frequency is more than ten times higher than the

highest frequency component of the 20 Hz to 20 kHz range of the audio input, providing excellent output resolution and easy filtering by the LPF.

3.2.3Bridge-Tied Load (BTL) Operation

The DMOS output transistors of the TPA005D12 class-D amplifier IC are arranged in an H-bridge configuration to allow BTL operation. In the BTL output mode, each half of the H-bridge operates 180° out of phase from the other. The load, in this case, a speaker, is then connected between the two halves, and is not connected directly to ground. The load is, in a sense, floating.

BTL operation has two main advantages over single-ended operation. First, it eliminates the need for a bulky output coupling capacitor to block any dc offset voltage that may be present (which reduces the speaker response and may damage the speaker). And second, it quadruples the output power that can be delivered to the load. For more information, see the TPA005D12 amplifier IC data sheet, TI Literature Number SLOS240.

To operate in the BTL output mode, the EVM output signal from Rout+/Lout+ must go through the speaker load and be returned directly to Rout±/Lout±, and NOT to system ground. This requires that the Rout±/Lout± lines be isolated not only from system ground, but also from each other and the out± lines of any other amplifiers in the system. The plug-n-play platform provides such isolated output lines, connecting the EVM output pins directly to left and right speaker connectors.

Details 3-7

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Texas Instruments TPA005D12 manual ±6. Class-D Input and Output Waveforms, Bridge-Tied Load BTL Operation
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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.
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