SWITCHED CURRENT FILTERS

'Switched Currents' is a new analogue sampled-data signal processing technique that can be implemented without the need for linear floating capacitors. This feature enables signal processors to be integrated in a standard digital VLSI process (CMOS), making the technique ideally suited for mixed analogue/digital ICs. Switched current cells are described, and a configuration for a universal integrator is developed that is exactly equivalent to a switched capacitor counterpart. With this integrator, complete switched current filters may be constructed from switched capacitor prototypes. This is demonstrated by the 'exact' design and simulation of a sixth order lowpass filter with a cutoff frequency of 5 MHz.