Current Feedforward Phase Compensation Technique for an Integrator and Its Application to an Auto-Compensation System


IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E85-A    No.6    pp.1192-1199
Publication Date: 2002/06/01
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Papers Selected from 2001 International Technical Conference on Circuits/Systems, Computers and Communications (ITC-CSCC 2001))
analog integrated circuits,  integrator,  phase compensation,  autotuning system,  continuous-time filters,  

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The transfer characteristic of an integrator is affected by excess-phase shift caused by the parasitic capacitance. The phase compensation is obtained by introducing zeros to generate phase lead. This paper proposes a phase compensation technique for the differential signal input integrator. The proposed technique is employing feedforward signal current source. The fifth-order leapfrog Chebyshev low-pass filter with 0.5 dB passband ripple is designed using the integrator with the proposed phase compensation. Further, an autotuning phase compensation system using the proposed technique is realized by applying a PLL system. The effectiveness of the proposed technique is confirmed by PSPICE simulation. The simulation results of the integrator with the proposed phase compensation shows that excess-phase cancellation is obtained at various unity gain frequencies. The accurate filter characteristic of the fifth-order leapfrog filter is obtained by using the autotuning phase compensation system. The passband of the filter is improved over wide range of frequencies. The proposed technique is suitable for low voltage application.