SLOS989B November 2017 – November 2019 TAS5720A-Q1
PRODUCTION DATA.
Following the digital clipper, the interpolated audio data is next sent to the Closed-Loop Class-D amplifier, whose first stage is Digital to PWM Conversion (DPC) block. In this block, the stereo audio data is translated into two pairs of complimentary pulse width modulated (PWM) signals which are used to drive the outputs of the speaker amplifer. Feedback loops around the DPC ensure constant gain across supply voltages, reduce distortion, and increase immunity to power supply injected noise and distortion. The analog gain is also applied in the Class-D amplifier section of the device. The gain structures are discussed in detail below for both Hardware Control Mode and Software Control Mode.
The switching rate of the amplifier is configurable in both Hardware Control Mode and Software Control Mode. In both cases, the PWM switching frequency is a multiple of the sample rate. This behavior is described in the respective Hardware Control Mode and Software Control Mode sections below.