Inter Chip Limiter Alignment in TAx5xxx-Q1 Devices

Abstract

The TAx5xxx family of audio CODECs and DACs are stereo, high-performance converters for audio applications, with the TAx5xxx-Q1 variants tailored for automotive use.

The TAx5xxx-Q1 series, exclusively TAC5xxx-Q1 and TAD5xxx-Q1, incorporate the Limiter Bank algorithm, which use the Distortion Limiter, Brown-Out Protection, and Thermal Foldback feature to adjust output based on VBAT or AVDD levels. The Limiter Bank algorithm is covered in the Dynamic Voltage and Temperature Tracking Based Limiter in TAx5xxx-Q1, application note.

This article explains how to configure multiple TAx5xxx and TAx5xxx-Q1 devices for synchronized output attenuation of the limiter bank.

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1 Introduction

The TAx5xxx-Q1 device incorporates a dynamic Limiter Bank algorithm designed to enhance audio performance and protect system integrity. This algorithm includes several key features:

Distortion Limiter
Prevents audio distortion by automatically adjusting the output levels during high volume peaks or drops in battery voltage.
Brown-Out Protection
Safeguards against voltage drops, making sure of consistent audio performance.
Thermal Foldback
Reduces output levels to prevent overheating and protect the device.

In automotive audio applications, these features make sure of high quality audio delivery and equipment reliability. For example, the Distortion Limiter maintains sound clarity during sudden volume changes, while Brown-Out Protection makes sure of stable operation despite fluctuations in a vehicle's electrical system. Thermal foldback prevents damage to audio components, such as speaker amplifiers driven by the device, during extended use, making sure of long term durability.

The Inter-Chip Limiter Alignment (ICLA) supports the synchronization of limiter functions across multiple devices. This process is crucial in modern vehicles equipped with multi-speaker systems, making sure of consistent output attenuation and audio quality throughout the vehicle, maintaining a balanced and high-fidelity sound experience.

2 Signal Chain Architecture

For systems with up to 8 analog input channels, 8 digital input channels, or 16 digital microphone inputs routed through the DAC signal chain, four TAx5xxx-Q1 devices can synchronize gain adjustments with the ICLA algorithm. TAx5xxx-Q1 supports a shared I²C control bus and audio serial bus using a time-division multiplexed (TDM), Inter-IC Sound (I²S), or Left-justified (LJ) interface. Figure 2-1 shows a diagram of four TA(C/D)5XXX devices connected for ICLA with digital inputs on a shared audio serial bus.

Figure 2-1 Playback Signal Path Configuration

Figure 2-2 shows a diagram of four TAC5xxx-Q1 devices connected for ICLA with 8 analog channels.

Figure 2-2 Record and Playback Signal Path Configuration

Internal ADC channel output loopback is not supported when configuring more than 2 devices for ICLA synchronization due to slot reservation for ICLA communication. Figure 2-3 shows a diagram for routing multiple devices to record and playback with a manual loopback circuit design.

Figure 2-3 Record and Playback Path with Loopback