Frequency calibration circuit and method thereof

Abstract

The invention provides a frequency calibration circuit and a method thereof. The frequency calibration circuit comprises a phase lock loop circuit, an M-dividing divider for generating a plurality of phase signals, a sampling circuit for sampling on the rising edges of the phase signals, a first counter for counting reference frequency signals, a second counter counting first phase signals, a logical control circuit for comparing a count value with a target count value to obtain a minimum difference value, and looking up a control bit of a voltage-controlled oscillator through the difference value, and a comparison circuit for judging whether the control voltage of the voltage-controlled oscillator is in a set range or not. The method comprises the following steps: sampling the reference frequency signals to obtain a total count value; comparing the total count value with a target count value; selecting a next resonance line according to a binary lookup flow till binary lookup ends; and outputting a resonance line corresponding to a minimum error in order that the output frequency of the voltage-controlled oscillator reaches a required value. Through adoption of the frequency calibration circuit and the method thereof, the speed and accuracy are increased, and the requirement on the working frequency of a digital circuit is lowered, so that a design method is simplified.

Description

technical field [0001] The invention relates to the field of integrated circuits, in particular to a frequency calibration circuit and a method thereof. Background technique [0002] In the field of wireless communication, a phase-locked loop frequency synthesizer (Phase Lock Loop, PLL) is an essential part of a wireless transceiver chip. A phase-locked loop circuit generates a stable, low-phase-noise signal at a certain frequency. In modern wireless communication chips, due to the increasing number of wireless communication protocols, considering cost and market factors, wireless transceiver chips that support multiple frequency bands and multiple modes have become mainstream. Therefore, the phase-locked loop module needs to support multi-band output. Since multiple phase-locked loops will inevitably bring about problems of power consumption and excessive area, a broadband single phase-locked loop circuit has become the mainstream of the market. [0003] In the phase-loc...

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Problems solved by technology

[0009] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a frequency calibration circuit and its method, which are used to solve the problems of slow speed and low precision of the frequency calibration technology in the prior art.

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