PLL circuit for radar

Patent metadata

Field	Value
Publication number	US-10536154-B2
Application number	US-201916504801-A
Country	US
Kind code	B2
Filing date	Jul 8, 2019
Priority date	Feb 8, 2017
Publication date	Jan 14, 2020
Grant date	Jan 14, 2020

Abstract

In a PLL circuit, a multi-band control oscillator includes multiple bands gradually increasing or decreasing a frequency in accordance with a control signal and being separated from each other, is capable of selectively switching one band among the multiple bands, and generates a signal of a frequency corresponding to the control signal in the band that is switched as a reference signal. A band setting unit sets the band of the multi-band control oscillator. The band setting unit sets the band for a present or subsequent time after a control command generator finishes outputting the control command to gradually increase or decrease from a previous start frequency to a previous stop frequency and before the control command generator starts outputting the control command to gradually increase or decrease from a present start frequency.

First claim

What is claimed is:

1. A phase locked loop (PLL) circuit for radar configured to generate a reference signal and to be used in a radar system including a transmitter, a receiver, and a control command generator, the transmitter generating a radar transmission wave in response to the reference signal and transmitting the radar transmission wave to a target object, the receiver receiving a reflected signal reflected from the target object in response to the reference signal, the control command generator generating and outputting a control command to the PLL circuit, the PLL circuit comprising:
a multi-band control oscillator having a plurality of bands that gradually increases or decreases a frequency in response to a control signal and is separated from each other, the multi-band control oscillator configured to be capable of selectively switching one band among the plurality of bands, and configured to generate a signal of a frequency corresponding to the control signal in the band that is switched as the reference signal;
a band setting unit configured to set the band of the multi-band control oscillator; and
a monitor unit configured to monitor the control signal changing in accordance with an input frequency command before the control command generator starts outputting the control command to gradually increase or decrease the frequency from a present start frequency, wherein
the band setting unit is configured to set the band to be used for a present or subsequent time after the control command generator finishes outputting the control command to gradually increase or decrease the frequency from a previous start frequency to a previous stop frequency and before the control command generator starts outputting the control command to gradually increase or decrease the frequency from the present start frequency, and
the monitor unit is configured to monitor a value of the control signal and to determine whether the value of the control signal falls within a predetermined range, and the band setting unit is configured to set a band to be used for the present or subsequent time to fall within the predetermined range by adding an offset to or subtracting an offset from information on the previous band when the value does not fall within the predetermined range.

2. The PLL circuit according to claim 1 , wherein
the band setting unit is configured to set the band to be used for the present time.

3. The PLL circuit according to claim 1 , wherein
the band setting unit is configured to set the band to be used for a next time subsequent to the present time.

4. The PLL circuit according to claim 1 , further comprising
a band calibrator configured to calibrate which band the frequency corresponding to the control signal corresponds to in advance based on a comparison result of comparing a phase of a reference clock with a phase of a signal obtained by dividing an output signal of the multi-band control oscillator, wherein
the band setting unit is configured to set the band with reference to the calibration result.

5. A phase locked loop (PLL) circuit for radar configured to generate a reference signal and to be used in a radar system including a transmitter, a receiver, and a control command generator, the transmitter generating a radar transmission wave in response to the reference signal and transmitting the radar transmission wave to a target object, the receiver receiving a reflected signal reflected from the target object in response to the reference signal, the control command generator generating and outputting a control command to the PLL circuit, the PLL circuit comprising:
a multi-band control oscillator having a plurality of bands that gradually increases or decreases a frequency in response to a control signal and is separated from each other, the multi-band control oscillator configured to be capable of selectively switching one band among the plurality of bands, and configured to generate a signal of a frequency corresponding to the control signal in the band that is switched as the reference signal;
a band setting unit configured to set the band of the multi-band control oscillator; and
a monitor unit configured to monitor the control signal changing in accordance with an input frequency command before the control command generator starts outputting the control command to gradually increase or decrease the frequency from a present start frequency, wherein
the band setting unit is configured to set the band to be used for a present or subsequent time after the control command generator finishes outputting the control command to gradually increase or decrease the frequency from a previous start frequency to a previous stop frequency and before the control command generator starts outputting the control command to gradually increase or decrease the frequency from the present start frequency, and
the monitor unit is configured to monitor a value of the control signal and to compare the value of the control signal with a low threshold of a predetermined plurality of stages and a high threshold of a plurality of stages, and the band setting unit is configured to subtract an offset of a multiple corresponding to a difference between the control signal and the low threshold from information on a previous band when the value of the control signal is smaller than the low threshold to set a band to be used for the present or subsequent time, and is configured to add an offset of a multiple corresponding to a difference between the control signal and the high threshold to the information on the previous band when the value of the control signal is larger than the high threshold to set the band to be used for the present or subsequent time.

6. The PLL circuit according to claim 5 , wherein
the band setting unit is configured to set the band to be used for the present time.

7. The PLL circuit according to claim 5 , wherein
the band setting unit is configured to set the band to be used for a next time subsequent to the present time.

8. The PLL circuit according to claim 5 , further comprising
a band calibrator configured to calibrate which band the frequency corresponding to the control signal corresponds to in advance based on a comparison result of comparing a phase of a reference clock with a phase of a signal obtained by dividing an output signal of the multi-band control oscillator, wherein
the band setting unit is configured to set the band with reference to the calibration result.

9. The PLL circuit according to claim 1 , wherein
the multi-band control oscillator is configured to output the reference signal to the transmitter and the receiver,
the band setting unit is connected to the multi-band control oscillator, the control command generator, and the monitor unit, and
the control command generator is connected to the monitor unit.

10. The PLL circuit according to claim 1 , wherein
the band setting unit is a band control logic.

11. The PLL circuit according to claim 1 , wherein
the monitor unit is a level comparator.

12. The PLL circuit according to claim 1 , further comprising
a precharge voltage applicator configured to output a control voltage as the control signal to the multi-band control oscillator.

13. The PLL circuit according to claim 5 , wherein
the multi-band control oscillator is configured to output the reference signal to the transmitter and the receiver,
the band setting unit is connected to the multi-band control oscillator, the control command generator, and the monitor unit, and
the control command generator is connected to the monitor unit.

14. The PLL circuit according to claim 5 , w

Assignees

• Denso Corp

Inventors

• Kitamura Tomomitsu

Classifications

• G01S13/343

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• G01S2013/93271

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• G01S13/931

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• G01S13/584

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• G01S13/50

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