Title :
A Second-Order Sigma-Delta Modulator with Switched-Current Memory Cell for Closed-Loop Motor Control System
Author :
Guo-Ming Sung ; Dong-An Yao ; Kuo-Hsuan Chang ; Shyue-Ru Yao
Author_Institution :
Dept. of Electr. Eng., Nat. Taipei Univ. of Technol.
Abstract :
This paper presents the design and implementation of a second-order switched-cur rent (SI) sigma-delta modulator (SDM) used in motor control system. To complete this technique, a current-mode sample-and-hold circuit is proposed. It consists of a feedback circuit to reduce the impedance at the input and a common-mode feedforward (CMFF) circuit to improve the common-mode offset at the output. Furthermore, a coupled differential (CDR) feedback memory cell (FMC) is used with CMFF SI memory cell to eliminate the clock feedthrough (CFT) error considerably. All the proposed circuits establish the second-order sigma-delta modulator and simulate with the parameters of the TSMC 0.35 mum CMOS process technology. The simulation results reveal that the maximum signal to noise plus distortion ratio (SNDR) is about 87 dB, which is equal to 14 bits resolution, within the conditions that the sampling rate is a value of 5.12 MHz and the oversampling ratio is 256. Note that the power dissipation is about 11 mW, which is considerably low
Keywords :
CMOS integrated circuits; circuit feedback; closed loop systems; feedforward; machine control; modulators; motor drives; sample and hold circuits; sigma-delta modulation; switched current circuits; CMOS process technology; TSMC; clock feedthrough error; closed-loop motor control system; common-mode feedforward circuit; common-mode offset; coupled differential feedback memory cell; current-mode sample-and-hold circuit; feedback circuit; impedance reduction; power dissipation; second-order sigma-delta modulator; signal to noise plus distortion ratio; switched-current memory cell; CMOS process; CMOS technology; Circuit noise; Circuit simulation; Clocks; Coupling circuits; Delta-sigma modulation; Feedback circuits; Impedance; Motor drives;
Conference_Titel :
Power Electronics Specialists Conference, 2006. PESC '06. 37th IEEE
Conference_Location :
Jeju
Print_ISBN :
0-7803-9716-9
DOI :
10.1109/PESC.2006.1711840