A Low-Power Second-Order Double-Sampling Delta-Sigma Modulator for Audio Applications

This paper proposes a low-power double-sampling delta-sigma (Delta Sigma) modulator for audio applications. The proposed modulator adopts a second-order cascade of integrators feedforward type and employs an adaptive current saving scheme for the low power operation. The adaptive current control logic senses the output transition of integrator and controls the bias current of operational transconductance amplifiers. The proposed Delta Sigma modulator is fabricated using a 0.18-mu m CMOS process. The measurement result shows that the power consumption of the proposed Delta Sigma modulator is reduced from 2.57 mW to 1.93 mW without sacrificing the signal-to-noise ratio.