Reconfigurable Σ-Δ Continuous-Time Modulator for Audio Applications
Based on a 180 nm CMOS process,a sigma-delta continuous-time modulator with reconfigurable feedforward third-order operation was designed for audio applications.The traditional sigma-delta continuous time modulator has only one operating mode,but the proposed modulator with the reconfigurable integrator has two operating modes:high-resolution and low-power consumption modes.In addition,summation ahead is used to reduce the power consumption of the modulator,negative-R compensation is used to improve the SNDR of the modulator,and excess loop delay compensation is used to improve the stability of the modulator.With a signal bandwidth of 20 kHz and supply voltage of 1.8 V,the modulator has an SNDR of 94.7 dB and power consumption of 291 μW in the low-power consumption mode and an SNDR of 108 dB and power consumption of 436.6 μW in the high-resolution mode.
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