CMOS current convevor and its filter applications
AssigneeIndustrial Technology Research Institute
InventorsShen-Iuan Liu, Jing-Shown Wu, Hen-Wai Tsao
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Abstract
A CMOS second generation current conveyor (CCII) and its integrators suitable for MOS technology integrated circuit (IC) applications. Ladder filters based on CCII are realized. CMOS CCII-based circuits can be directly employed in single CCII biquad filters. Four configurations are proposed to synthesize various types of second-order transfer functions.
Claims27
A continuous-time signal processing system using a second generation current conveyor (CCII) having X and Y input terminals, and Z output terminal with characteristics that the voltages at said X and Y terminals are equal, zero current at said Y terminal, and equal currents at said X and Z terminals, comprising:
- a differential pair of transistors, a first generation current conveyor and a first current mirror;
- said differential pair having inputs serving as said X and Y terminals and having differential outputs driving directly two inputs of said first generation current conveyor forming a voltage-to-current converter;
- said voltage-to-current converter driving said first current mirror;
- said first generation current conveyer output fed back to said X terminal;
- said first generation current conveyor comprising:
- a first p-channel MOSFET current mirror,
- an n-channel MOSFET current mirror,
- said first p-channel MOSFET current mirror and said n-channel MOSFET current mirror having inputs and outputs cross-coupled,
- drains of said p-channel MOSFETs in said first p-channel MOSFET current mirror connected to a positive power supply,
- two sources of n-channel MOSFETs in said n-channel MOSFET current mirror connected separately to two drains of two other n-channel MOSFETs used as said differential pair, and serving as inputs to said first generation current conveyor,
- a second p-channel MOSFET current mirror connected to convey an output current at said Z terminal mirroring currents at said inputs to said first generation current conveyor to function as a positive second generation current conveyor.
Dependencies are inferred from the claim text.