US-12627383-B2 - Calibration circuit, calibration method for filter and filter device

US12627383B2US 12627383 B2US12627383 B2US 12627383B2US-12627383-B2

Abstract

Disclosed is a calibration circuit, a calibration method for a filter and a filter device. The calibration circuit includes: a signal receiving terminal, receiving an output signal from the filter; a frequency detection module, obtaining a count value according to the output signal, the count value representing a frequency of the output signal; an adjustment module, adjusting the control signal according to the count value and a target value representing a target frequency, to adjust the frequency of the output signal provided by the filter until a calibration value, which allows the count value to be consistent with the target value, of the control signal is determined. The filter performs filtering according to the control signal with the calibration value in an operating stage. The calibration circuit performs feedback adjustment on the filter to achieve bandwidth calibration with high calibration accuracy and simple circuit structure.

Inventors

Zhiyong Chen
Yangyang Li

Assignees

Beijing Eswin Computing Technology Co., Ltd.
Guangzhou Transa Semi Information Technology Co., Ltd.

Dates

Publication Date: 20260512
Application Date: 20230202
Priority Date: 20220523

Claims (14)

1 . A calibration circuit for a filter, which is configured to perform filtering under configuration of a control signal to provide an output signal, wherein the calibration circuit comprises: a signal receiving terminal, connected with the filter and configured to receive the output signal from the filter; a frequency detection module, connected with the signal receiving terminal and configured to obtain a count value according to the output signal, the count value representing a frequency of the output signal; and an adjustment module, connected with the frequency detection module and configured to adjust the control signal according to the count value and a target value representing a target frequency, so as to adjust the frequency of the output signal provided by the filter until a calibration value, which allows the count value to be consistent with the target value, of the control signal is determined; wherein the filter is configured to perform filtering according to the control signal with the calibration value in an operating stage, wherein the adjustment module is configured to: calculate a difference value between the count value and the target value to provide a difference value signal; adjust the control signal according to the difference value signal; and store the control signal that allows the difference value to be relatively small and sending that control signal to the filter, wherein the control signal is used for controlling conduction states of various filter components in the filter, wherein: when the count value is consistent with the target value, the difference value signal of a first error sign bit is provided; when the count value is inconsistent with the target value and the count value is greater than the target value, the difference value signal of a second error sign bit of a first voltage level is provided; when the count value is inconsistent with the target value and the count value is less than the target value, the difference value signal of a second error sign bit of a second voltage level is provided.
2 . The calibration circuit according to claim 1 , wherein the adjustment module is further configured to provide an initial value of the control signal, so that the filter is configured to first provide the output signal with an initial frequency according to the control signal with the initial value in an initiating stage prior to the operating stage.
3 . The calibration circuit according to claim 2 , wherein the adjustment module is configured to store a plurality of the control signals with different initial values, and after the target value is obtained, the adjustment module is configured to select one of the control signals that minimizes a difference value between the initial frequency of the output signal and the target frequency and provide the selected control signal to the filter.
4 . The calibration circuit according to claim 1 , wherein the frequency detection module comprises: a level shifter, connected to the signal receiving terminal and configured to amplify the output signal; a comparator, connected to the level shifter and configured to compare an amplitude of the amplified output signal with a reference value to generate a square wave signal; and a counter, connected to the comparator and configured to count a rising edge of the square wave signal to obtain the count value.
5 . The calibration circuit according to claim 1 , wherein the adjustment module comprises: a difference value calculating circuit, configured to calculate the difference value between the count value and the target value to provide the difference value signal; a dichotomy calculating circuit, configured to adjust the control signal according to the difference value signal; and a storage unit, configured to store an initial value of the control signal, the control signal that allows the difference value to be relatively small, and the calibration value of the control signal.
6 . The calibration circuit according to claim 1 , wherein the adjustment module further comprises a register for storing the target value.
7 . A filter device, comprising the filter and the calibration circuit according to claim 1 , the calibration circuit being connected with the filter, wherein the filter is configured to perform filtering on the input signal to obtain an output signal; and the calibration circuit is configured to provide the control signal to adjust the frequency of the output signal to the target frequency.
8 . The filter device according to claim 7 , wherein the filter is configured to first provide the output signal with an initial frequency according to the control signal with an initial value in an initiating stage, and perform filtering according to the control signal with the calibration value in the operating stage after the initiating stage.
9 . The filter device according to claim 7 , wherein the filter comprises a plurality of filter components, and the control signal is used for controlling conduction states of the plurality of filter components, thereby adjusting the frequency of the output signal, wherein the plurality of filter components comprise a capacitor array and/or a resistor array.
10 . The calibration circuit according to claim 1 , wherein the frequency detection module is configured to store a plurality of detected count values obtained in a plurality of consecutive time periods, respectively, calculate an average value of the plurality of detected count values when a difference between the plurality of detected count values is within a preset error range, and output the average value as the count value to the adjustment module.
11 . A calibration method for a filter, which is configured to perform filtering under configuration of a control signal to provide an output signal, wherein the calibration method comprises: receiving the output signal from the filter; obtaining a count value according to the output signal, the count value representing a frequency of the output signal; and adjusting the control signal according to the count value and a target value representing a target frequency, so as to adjust a frequency of the output signal provided by the filter until a calibration value, which allows the count value to be consistent with the target value, of the control signal is determined; wherein the filter performs filtering according to the control signal with the calibration value in an operating stage, wherein step of adjusting the control signal according to a comparison result between the count value and the target value representing the target frequency comprises: calculating a difference value between the count value and the target value to provide a difference value signal; adjusting the control signal according to the difference value signal, the control signal being used for controlling conduction states of various filter components in the filter; and storing the control signal that allows the difference value to be relatively small and sending that control signal to the filter, wherein: when the count value is consistent with the target value, the difference value signal of a first error sign bit is provided; when the count value is inconsistent with the target value and the count value is greater than the target value, the difference value signal of a second error sign bit of a first voltage level is provided; when the count value is inconsistent with the target value and the count value is less than the target value, the difference value signal of a second error sign bit of a second voltage level is provided.
12 . The calibration method according to claim 11 , wherein the filter is configured to first provide the output signal with an initial frequency according to the control signal with an initial value in an initiating stage prior to the operating stage.
13 . The calibration method according to claim 12 , further comprising: storing a plurality of the control signals with different initial values, and after the target value is obtained, selecting one of the control signals that minimizes a difference value between the initial frequency of the output signal and the target frequency and providing the selected control signal to the filter.
14 . The calibration method according to claim 11 , wherein step of obtaining the count value according to the output signal comprises: amplifying the output signal; comparing an amplitude of the amplified output signal with a reference value to generate a square wave signal; and counting a rising edge of the square wave signal to obtain the count value.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority to Chinese Patent Application No. 202210564495.5, filed on May 23, 2022, entitled by “CALIBRATION CIRCUIT, CALIBRATION METHOD FOR FILTER AND FILTER DEVICE”, and published as CN115021716A on Sep. 6, 2022, which is incorporated herein by reference in its entirety. TECHNICAL FIELD The present disclosure relates to a technical field of integrated circuits, and in particular to a calibration circuit, a calibration method for a filter and a filter device. BACKGROUND With the development of science and technology, communication systems are increasingly applied in the fields of education, transportation, scientific research, daily life, etc. In a receiver of the communication system, a filter is an indispensable module. The bandwidth is one of important parameters of the filter. If the bandwidth is too high, the noise performance of the system may be deteriorated and even the linearity of the system may be affected; and if the bandwidth is too low, a useful signal may be filtered out, so that error rate may be increased and the performance of the receiver may be reduced. Therefore, it is very important to precisely control the bandwidth of the filter. When the filter has an appropriate bandwidth, it can effectively filter out-of-band noise and interference, and can improve sensitivity of the receiver. However, the filter in the art is difficult to provide an accurate bandwidth. SUMMARY The present disclosure provides a calibration circuit, a calibration method for a filter and a filter device, so as to improve accuracy of a filtering bandwidth. According to a first aspect of the present disclosure, a calibration circuit for a filter is provided, the filter is configured to perform filtering under configuration of a control signal to provide an output signal, the calibration circuit comprises: a signal receiving terminal, connected with the filter and used for receiving the output signal from the filter; a frequency detection module, connected with the signal receiving terminal and configured to obtain a count value according to the output signal, the count value representing a frequency of the output signal; and an adjustment module, connected with the frequency detection module and configured to adjust the control signal according to the count value and a target value representing a target frequency, so as to adjust the frequency of the output signal provided by the filter until a calibration value, which allows the count value to be consistent with the target value, of the control signal is determined; wherein the filter is configured to perform filtering according to the control signal with the calibration value in an operating stage. The calibration circuit can adjust the frequency of the output signal of the filter to the target frequency, thus feedback adjustment of the filter itself can be achieved, bandwidth calibration accuracy can be high and circuit structure can be simple, embodiments of the present disclosure have advantages of high integration degree, accurate bandwidth and low power consumption. Optionally, the adjustment module is further configured to provide an initial value of the control signal, so that the filter firstly provides the output signal with an initial frequency according to the control signal with the initial value in an initiating stage prior to the operating stage. In this technical solution, configuration of the initial value can realize an effective control on the filter in different stages based on the control signal, so that the circuit structure can be further simplified. Optionally, the adjustment module is configured to store a plurality of the control signals with different initial values, and after the target value is obtained, the adjustment module is configured to select one of the control signals that minimizes a difference value between the initial frequency of the output signal and the target frequency and provide the selected control signal to the filter. In this technical solution, selecting an appropriate initial value of the control signal according to the target frequency can save the time required for bandwidth calibration and reduce the power consumption of the circuit. Optionally, the frequency detection module comprises: a level shifter, connected to the signal input terminal and configured to amplify the output signal; a comparator, connected to the level shifter and configured to compare an amplitude of the amplified output signal with a reference value to generate a square wave signal; and a counter, connected to the comparator and configured to count a rising edge of the square wave signal to obtain the count value. In this technical solution, the arrangement of the level shifter is beneficial to frequency detection performed on the output signal with low voltage amplitude. It should be understood that in some practical applications, the level shifter can be omitted; the freq