Adjustable capacitance circuit and delay adjusting circuit

Abstract

The invention discloses an adjustable capacitor circuit and a delay adjusting circuit. The adjustable capacitance circuit comprises at least one capacitance adjusting unit; the capacitance adjusting unit comprises a triode, at least one capacitor and a loop module, the triode and the capacitor are connected in series between the first port and the second port of the adjustable capacitance circuit, the base electrode of the triode is connected with the control signal end, and the loop module is connected with the triode and used for providing a conduction loop for the triode. The parasitic capacitance of the triode is very small, the minimum value of the capacitance value adjusting range of the capacitance adjusting unit can be reduced, the variable capacitance ratio of the capacitance adjusting unit is increased, and therefore the variable capacitance ratio of the adjustable capacitance circuit can be increased, and the adjustable capacitance circuit can be used in a high-speed circuit. Meanwhile, the adjustable capacitor circuit is added to change the value range of the time constant when the node time constant is changed, or the value range of the time delay duration when the adjustable capacitor circuit is used for the time delay circuit is increased, so that the application range of the adjustable capacitor circuit is increased.

Description

technical field [0001] The embodiments of the present invention relate to the technical field of electronic circuits, in particular to an adjustable capacitance circuit and a delay adjustment circuit. Background technique [0002] As a basic circuit structure, the adjustable capacitance circuit can be widely used in circuits that need to change the node time constant or delay time. For example, in the delay circuit, by setting an adjustable capacitance circuit for adjusting the equivalent capacitance value of the delay circuit, the delay time of the delay circuit can be changed. [0003] In the prior art, the adjustable capacitance circuit may include an adjustable capacitance device for adjusting the capacitance value, for example, the adjustable capacitance device may be a voltage-controlled adjustable capacitance. The adjustment range of the capacitance value of the adjustable capacitor device is relatively small, which is not conducive to realizing a wide range of capac...

AI Technical Summary

Problems solved by technology

Due to the large parasitic capacitance of the MOS tube, the variable capacitance ratio of the adjustable capacitor circuit is relatively small, which limits the scope of use of the adjustable capacitor circuit.

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