Energy Metering Applies To The 16 ΣΔ Modulator

Based on SMIC0.35μmCMOS technology, the use of IC design and EDA simulation tool, designed a mainly used in electric energy measurement of 16Σ△modulator, the modulator using 5V single power supply, the sampling frequency of 900kHz, Sampling rate for the 256, the input signal bandwidth of 1.7 kHz, the use of feed-forward structure of second-order single-bit, circuit mainly by the realization of fully differential switched-capacitor.The design is mainly based on Matlab system-level simulation and based on the use of simulation tools Specter of its circuit-level design. The design of the main circuit module are: bandgap circuit, input buffer circuit, switched-capacitor integrator, op amp and comparator. In the bandgap circuit, the current reference temperature coefficient of 37ppm /℃, reference voltage temperature coefficient of 2.7ppm /℃; input buffer is to enable bipolar signal into the power supply by a single modulator designed; switch integrator capacitor is nothing to do with the parasitic capacitance of the in-phase switched-capacitor integrator structure, which used OPAMP folded cascode structure, used in the output stage switched capacitor common mode feedback to stabilize the output common-mode point, guarantee the normal work of OPAMP basis, be open-loop gain of 72dB, unity gain bandwidth of 47MHz, the conversion rate of 40 V /μs. Dynamic latched comparator hysteresis comparators, followed by SR flip-flop, when the input voltage difference is±1 V, the comparator is the amount of hysteresis 26.9848mV, amount of negative hysteresis 24.7784mV. Then also designed undervoltage protection circuit and Clock Generation Circuit. Finally, their overall circuit simulation, and MATLAB do its output modulation signal noise cancellation and FFT analysis, the SNDR for 112.3dB, ENOB for 18.37.