INTEGRATED MOSFET RESISTANCE AND OSCILLATOR FREQUENCY CONTROL AND TRIM METHODS AND APPARATUS

摘要

In an integrated circuit system, a filter and an oscillator are referenced to a common reference circuitry through a suitable control loop to provide filter time constant and oscillator frequency references. The oscillator (Fig. 3) and the filter (Fig. 4) are implemented in a manner where the monolithic pattern elements setting the fundamental control parameters (time-period and time-constant respectively) are of the same type. Monolithic capacitors are used as one of the common passive elements between the oscillator and the filter to set the time-period and time-constants, respectively, adjustable through adjustment of control currents (Iosc, Ix). The monolithic implementation of the Control Block (Fig. 3, Fig. 4 and Fig. 7) is such that by tuning the oscillator frequency to the appropriate value through setting of the respective control current (Iosc), the filter time-constants also are appropriately set to satisfy the Nyquist criteria for a sampling rate referenced to the oscillator frequency.