High-precision annular oscillator, and frequency calibration circuit and method thereof

Abstract

The invention discloses a high-precision annular oscillator, and a frequency calibration circuit and method thereof. The high-precision annular oscillator comprises a band gap reference circuit, a reference current circuit, a current adjusting circuit, an annular oscillation circuit and an output buffer circuit. The frequency calibration circuit comprises a frequency divider, a counter, a comparator, a register and a nonvolatile memory. The frequency calibration circuit can rapidly position the adjusting current needed by the high-precision annular oscillator and store an adjustment arrangement in the nonvolatile memory. According to the invention, the high-precision annular oscillator cooperates with the frequency calibration circuit so that the effects of temperature deviations, voltage deviations and technology deviations on oscillation frequencies can be compensated, and thus the high precision of the oscillation frequencies can be realized. Through the cooperation between the high-precision annular oscillator and the frequency calibration circuit, high-precision oscillation frequencies are obtained, at the same time a complex circuit is avoided, the area and power consumption of a chip are reduced, the non-linearity, error and noise of a simulation comparison circuit are avoided, the frequency precision is improved, and the testing time and cost of the chip are saved.

Description

technical field [0001] The invention relates to a high-precision ring oscillator and its frequency calibration circuit and frequency calibration method. Background technique [0002] Clocks are required for digital circuits to work. The need for precise time, such as communication requirements, necessitates a high-precision clock. For many years, the use of phase-locked loop circuits and reference external crystal oscillators to generate high-precision clocks has been standard for many circuits. However, the phase-locked loop circuit area and power consumption are large. At the same time, the reference external crystal oscillator on the circuit board increases the cost of the circuit system. In order to save the cost and power consumption of the circuit system, the high-precision ring oscillator has been the research direction of many circuit designers for many years. [0003] However, the basic principle of a ring oscillator is to generate an oscillating signal through ...

AI Technical Summary

Problems solved by technology

However, frequency voltage / frequency current conversion circuit and voltage comparator / current comparator require additional area and power consumption

More importantly, the frequency voltage / frequency current conversion circuit and the voltage comparator / current comparator are all analog circuits, and their own nonlinearity, error and noise will affect the circuit and affect the final frequency accuracy

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