Relaxation oscillator with process deviation calibration function

Abstract

The invention discloses a relaxation oscillator with a process deviation calibration function. The relaxation oscillator comprises a reference signal generator, an intrinsic oscillator, a time digital converter and a compensation capacitor array. The time digital converter comprises a comparator, a switched capacity circuit and a counter. The reference signal generator provides a first reference voltage to the switched capacity circuit and provides a second reference voltage to the comparator. An output frequency of the intrinsic oscillator controls the switched capacity circuit, an output voltage of the switched capacity circuit is connected with the comparator, and an output end of the comparator is connected with the counter. An output end of the counter is connected with the compensation capacitor array, the output of the counter automatically adjusts the capacitance of the compensation capacitor array and correspondingly changes the frequency of the intrinsic oscillator. According to the invention, the relaxation oscillator is provided with the on-chip calibration function, the error among chips is relatively small, the chip manufacturing cost is lowered, and the precision of chips is improved.

Description

[technical field] [0001] The invention relates to a clock generating circuit of an integrated circuit, which is a relaxation oscillator with a process deviation calibration function. [Background technique] [0002] The relaxation oscillator has been used in various electronic circuits, and the clock signal generated by it can replace the external crystal oscillator, which significantly reduces the complexity and cost of the system. The relaxation oscillator has the advantages of high frequency stability, good control linearity, and wide adjustable range, and is often used to generate clock signals for controlling circuit timing. For example, relaxation oscillator circuits can be used in DC / DC converters, counters, shifters, microcontrollers, and modulation circuits. [0003] Document 1 (X.Zou, X.Xu, L.Yao and Y.Lian, "A 1-V 450-nW Fully Integrated Programmable Biomedical Sensor Interface Chip," IEEE Journal of Solid-State Circuits, vol.44, no.4, pp.1067-1077, APRIL 2009) i...

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Problems solved by technology

[0008] The oscillators disclosed in the above documents do not have the function of eliminating process deviation through on-chip calibration, so they are greatly affected by process deviation, or although there is process deviation compensation, the cost is that the power consumption is very large

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