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CN-115085725-B - Lock detection circuit and phase lock device with lock detection function

CN115085725BCN 115085725 BCN115085725 BCN 115085725BCN-115085725-B

Abstract

The present invention relates to a lock detection circuit and a phase lock device having a lock detection function. The method comprises the steps of comparing pulse widths of two paths of output pulse signals of a phase discriminator in a phase lock device, outputting pulse width difference signals, judging whether the width difference value of the two paths of pulse signals is larger than a threshold value by a threshold value judging circuit according to the pulse width difference signals, if so, indicating that locking of the phase lock device is not in accordance with expectations, and if so, indicating that the locking result of the phase lock device is in an expected allowable range, and correspondingly outputting a first signal and a second signal to represent the situation. The lock judging device finally judges whether the phase lock device is locked or not according to the first signal and the second signal. The lock judging device can judge that the phase lock device is unlocked when the first signal is received, can monitor the frequency of the first signal in a preset time period, and judges that the phase lock device is not locked if the frequency of the first signal exceeds the preset frequency. Otherwise, the lock is judged by the rule. The implementation mode has high detection precision.

Inventors

  • FAN MINGJUN

Assignees

  • 上海联影微电子科技有限公司
  • 上海联影微电子科技有限公司

Dates

Publication Date
20260421
Application Date
20220721
Priority Date
20220721

Claims (8)

  1. 1. A lock detection circuit, comprising: the phase detector comprises a pulse width comparison circuit, a first input end, a second input end and a pulse width difference signal, wherein the first input end is used for accessing a first path of pulse signals output by the phase detector in the phase lock device, and the second input end is used for accessing a second path of pulse signals output by the phase detector and outputting the pulse width difference signal; The input end of the threshold judging circuit is connected with the output end of the pulse width comparison circuit, and the threshold judging circuit is used for outputting a first signal when judging that the pulse width difference value of the two paths of pulse signals is larger than a threshold value according to the pulse width difference signal and outputting a second signal when judging that the pulse width difference value of the two paths of pulse signals is smaller than or equal to the threshold value according to the pulse width difference signal; The locking judgment device comprises a threshold judgment circuit, a locking judgment circuit, a judgment result signal and a locking judgment circuit, wherein the input end of the locking judgment circuit is connected with the output end of the threshold judgment circuit and is used for outputting the judgment result signal according to the first signal and the second signal, the judgment result signal is used for representing whether the phase lock device is locked or not, the first signal is a pulse signal, the judgment result comprises a third signal and a fourth signal, the third signal is used for representing that the phase lock device is locked, the fourth signal is used for representing that the phase lock device is unlocked, and the locking judgment device comprises: The input end of the pulse counter is connected with the output end of the threshold judging circuit and is used for calculating the pulse number of the first signal; the locking judgment module is connected with the output end of the pulse counter, and is used for outputting the third signal when the pulse number in a preset time period is smaller than or equal to the preset times, and/or outputting the fourth signal when the pulse number in the preset time period is larger than the preset times; The lock judgment module includes: The input end of the shift register is connected with the output end of the pulse counter; and the input end of the judging device is connected with the output end of the shift register and is used for generating and outputting the judging result signal according to the signal output by the output end of the shift register.
  2. 2. The lock detection circuit according to claim 1, wherein the pulse width comparison circuit includes: and the input end of the first exclusive OR logic device is used for accessing two paths of pulse signals output by the phase discriminator, and the output end of the first exclusive OR logic device is connected with the input end of the threshold judging circuit.
  3. 3. The lock detection circuit according to claim 1, wherein the threshold judgment circuit includes: the input end of the delay module is connected with the output end of the pulse width comparison circuit; and the first input end of the first AND logic device is connected with the output end of the pulse width comparison circuit, the second input end of the first AND logic device is connected with the output end of the delay module, and the output end of the first AND logic device is connected with the input end of the locking judgment device.
  4. 4. The lock detection circuit of claim 1, wherein the pulse counter comprises: And the input end of the frequency divider is connected with the output end of the threshold judgment circuit, the output end of the frequency divider is connected with the input end of the locking judgment circuit, and the preset time period is related to the working parameters of the frequency divider.
  5. 5. The lock detection circuit of claim 1, wherein the pulse counter is a2 N divider and N is a positive integer greater than or equal to 1, and wherein the determiner comprises: The two input ends of each first exclusive-or non-logic device are respectively connected with the output ends of two adjacent shift registers in a one-to-one correspondence manner, and the input ends of different first exclusive-or non-logic devices are connected with the output ends of different shift registers; And the input end of the second AND logic device is connected with the output end of each first exclusive OR logic device and is used for outputting the judging result signals.
  6. 6. The lock detection circuit according to claim 1, wherein the pulse counter is a frequency divider, the shift registers are eight, and the determiner includes: the two input ends of each second exclusive-or non-logic device are respectively connected with the output ends of two adjacent shift registers in a one-to-one correspondence manner, and the input ends of different second exclusive-or non-logic devices are different output ends of the shift registers; the two input ends of each third AND logic device are correspondingly connected with the output ends of two adjacent second exclusive-or non-logic devices one by one, and the input ends of different third AND logic devices are connected with the output ends of different second exclusive-or non-logic devices; and the input end of the fourth AND logic device is connected with the output end of each third AND logic device and is used for outputting the judging result signals.
  7. 7. A phase lock device having a lock detection function, comprising: the lock detection circuit of any one of claims 1-6; the first input end of the phase discriminator is connected with a reference signal; the input end of the loop filter is connected with the output end of the phase discriminator; The input end of the voltage-controlled oscillator is connected with the output end of the loop filter; And the input end of the feedback loop is connected with the output end of the voltage-controlled oscillator, and the input end of the feedback loop is connected with the second input end of the phase discriminator.
  8. 8. The phase lock with lock detection function according to claim 7, further comprising: and the two input ends of the charge pump are connected with the two output ends of the phase discriminator in a one-to-one correspondence manner, and the output ends of the charge pump are connected with the input ends of the loop filter.

Description

Lock detection circuit and phase lock device with lock detection function Technical Field The present invention relates to the field of lock detection technology, and in particular, to a lock detection circuit and a phase lock device with lock detection function. Background The charge pump phase-locked loop is widely applied to circuits such as wireless communication, frequency synthesizer and clock recovery due to the characteristics of high stability, large capture range, convenient integration and the like. Phase-locked loop lock detection is of great importance for monitoring the operating characteristics of phase-locked loops. The analog lock detection commonly adopted in the conventional technology is to generate a pulse signal according to a phase difference output by a phase detector and charge and discharge an external capacitor to realize lock detection. However, in the implementation of the applicant, it is found that this lock detection method requires a long time to complete the output of the stable level signal, which would otherwise result in inaccurate lock detection. Disclosure of Invention Based on this, it is necessary to provide a lock detection circuit and a phase lock device with a lock detection function to solve the problem that the detection result of the above lock detection scheme is inaccurate. In a first aspect, an embodiment of the present application provides a lock detection circuit, including: The phase detector comprises a pulse width comparison circuit, a first input end, a second input end and a pulse width difference signal, wherein the first input end is used for accessing a first path of pulse signals output by the phase detector in the phase lock device, and the second input end is used for accessing a second path of pulse signals output by the phase detector and outputting the pulse width difference signal; The threshold judging circuit is used for outputting a first signal when judging that the pulse width difference value of the two paths of pulse signals is larger than a threshold value according to the pulse width difference signal and outputting a second signal when judging that the pulse width difference value of the two paths of pulse signals is smaller than or equal to the threshold value according to the pulse width difference signal; and the input end of the locking judgment device is connected with the output end of the threshold judgment circuit and is used for outputting a judgment result signal according to the first signal and the second signal, and the judgment result signal is used for representing whether the phase lock device is locked or not. In one embodiment, the first signal is a pulse signal, the judging result includes a third signal and a fourth signal, the third signal is used for representing that the phase lock device is locked, the fourth signal is used for representing that the phase lock device is not locked, and the locking judging device includes: The input end of the pulse counter is connected with the output end of the threshold judgment circuit and is used for calculating the pulse number of the first signal; The locking judgment module is connected with the output end of the pulse counter at the input end and is used for outputting a third signal when the pulse number in the preset time period is smaller than or equal to the preset times, and/or outputting a fourth signal when the pulse number in the preset time period is larger than the preset times. In one embodiment, the pulse width comparison circuit includes: And the input end of the first exclusive OR logic device is used for accessing two paths of pulse signals output by the phase discriminator, and the output end of the first exclusive OR logic device is connected with the input end of the threshold value judging circuit. In one embodiment, the threshold judgment circuit includes: The input end of the delay module is connected with the output end of the pulse width comparison circuit; The first input end of the first AND logic device is connected with the output end of the pulse width comparison circuit, the second input end of the first AND logic device is connected with the output end of the delay module, and the output end of the first AND logic device is connected with the input end of the locking judgment device. In one embodiment, the pulse counter comprises: the input end of the frequency divider is connected with the output end of the threshold value judging circuit, the output end of the frequency divider is connected with the input end of the locking judging circuit, and the preset time period is related to the working parameters of the frequency divider. In one embodiment, the lock determination module includes: the input end of the shift register is connected with the output end of the pulse counter; And the input end of the judging device is connected with the output end of the shift register and is used for generating and outputting a judging result signal a