A Delta-Sigma Modulator Using Dual NTF for 1-Bit Digital Switching Amplifier

摘要

In this paper, a fifth-order single-loop single-bit delta-sigma modulator (DSM) which is constructed by cascade-of-integrator feed-back (CIFB) form for a 1-bit digital audio switching amplifier is proposed. High order DSM can achieve high signal-to-noise ratio (SNR), but it has probability that the oscillation occur. To achieve high SNR and improve the stability of modulator for a large input range, we propose the DSM which is composed of dual noise transfer function (NTF). The one is high SNR mode that maximizes SNR of DSM and the other is stable mode that enhances stability of DSM. The proposed architecture is simulated in the register transfer level (RTL) and implemented in the FPGA board.