High accuracy oscillator and an auto-trimming method thereof
First Claim
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1. An oscillator, comprising:
- an oscillator unit, which generates an oscillation signal;
a frequency comparer, which receives the oscillation signal from the oscillator unit, and compares the frequency of a preset reference signal and the frequency of the oscillation signal based on a preset reference data, the preset reference data corresponding to a target frequency;
a Successive-Approximation-Register (SAR) comparer, which obtains initial control bits to control a frequency of the oscillator unit based on the comparing result of the frequency comparer; and
a post process module, which generates adjacent control bits based on the initial control bits, selects one of the initial control bits and adjacent control bits as final control bits based on a comparison of the preset reference data with the initial control bits and the adjacent control bits, and outputs the final control bits to the oscillator unit,wherein the oscillator unit performs auto-trimming based on the final control bits.
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Abstract
A high-accuracy oscillator obtains initial control bits to generate an initial signal and generates adjacent control bits to generate an adjusted signal from the oscillator based on the adjacent control bits. Characteristics of the initial signal and the adjacent signal are compared to a preset value to determine which of the initial signal and the adjusted signal is closer to a target signal. The closer of the initial signal and the adjusted signal to the target signal is output from the oscillator.
10 Citations
24 Claims
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1. An oscillator, comprising:
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an oscillator unit, which generates an oscillation signal; a frequency comparer, which receives the oscillation signal from the oscillator unit, and compares the frequency of a preset reference signal and the frequency of the oscillation signal based on a preset reference data, the preset reference data corresponding to a target frequency; a Successive-Approximation-Register (SAR) comparer, which obtains initial control bits to control a frequency of the oscillator unit based on the comparing result of the frequency comparer; and a post process module, which generates adjacent control bits based on the initial control bits, selects one of the initial control bits and adjacent control bits as final control bits based on a comparison of the preset reference data with the initial control bits and the adjacent control bits, and outputs the final control bits to the oscillator unit, wherein the oscillator unit performs auto-trimming based on the final control bits. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An auto-trimming method of an oscillator, the method comprising:
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comparing a frequency of a preset reference signal and a frequency of an oscillation signal based on a preset reference data, the preset reference data corresponding to a target frequency of the oscillation signal; generating initial control bits based on the comparison result; and selecting one of the initial control bits and adjacent control bits as final control bits by comparing a first difference between the initial control bits and the preset reference data and a second difference between the adjacent control bits and the preset reference data, wherein an oscillator unit performs auto-trimming based on the final control bits. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A method of controlling an oscillator, the method comprising:
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determining initial control bits to generate an initial frequency by counting oscillation periods of the oscillator over a predetermined period of time; generating adjacent control bits by changing a value of the initial control bits by one bit; determining which of the initial frequency and an adjusted frequency corresponding to the adjacent control bits is closer to a target frequency of the oscillation signal; and setting the closer of the initial frequency and the adjusted frequency as an operating frequency of the oscillator, wherein determining which of the initial frequency and the adjusted frequency is closer to the target frequency comprises; generating an adjusted oscillation signal with the adjacent control bits; counting an adjusted number of oscillation periods over the predetermined period of time; calculating an absolute value of the preset count number subtracted from the number of counted oscillation periods corresponding to the initial control bits; and obtaining an absolute value of the preset count number subtracting the adjusted number of oscillation periods. - View Dependent Claims (19, 20)
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21. A method of controlling an oscillator, the method comprising:
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setting highest-level control bit to a value of 1 and each of other control bits to a value of 0 in order from second highest-level to lowest-level control bit, respectively, where the control bits control a frequency of a signal output from the oscillator; generating a signal corresponding to the set control bit; and determining whether to maintain the set control bit at 1 or to change the control bit to 0 by comparing the number of counted oscillation periods of the generated signal with a predetermined number of oscillation periods, wherein determining whether to maintain the set control bit at 1 or to change the control bit to 0 comprises; setting a threshold number to correspond to a target frequency; counting a number of periods of a reference signal and generating the signal corresponding to the set control bit while the number of periods of the reference signal is less than the threshold number, and determining the number of counted oscillation periods of the generated signal when the counted number of periods of the reference signal reaches the threshold number; comparing the number of counted oscillation periods of the generated signal with a preset number corresponding to the target frequency; and maintaining the set bit as a 1 when the number of counted oscillation periods of the generated signal is greater than or equal to the preset number, and setting the set bit to 0 when the number of counted oscillation periods of the generated signal is greater than the preset number.
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22. An oscillator circuit, comprising:
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an oscillator; a frequency comparer to compare a frequency of a preset reference signal and a frequency of an oscillation signal based on a preset reference data, the preset reference data corresponding to a target frequency of the oscillation signal; a Successive-Approximation-Register (SAR) comparer to determine initial control bits to generate an initial frequency according to the comparison result; and a post process module to generate adjacent control bits by changing a value of the initial control bits by one bit, to determine which of the initial frequency and an adjusted frequency corresponding to the adjacent control bits is closer to a target frequency, and to set the closer of the initial frequency and the adjusted frequency as an operating frequency of the oscillator. - View Dependent Claims (23)
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24. A microchip, comprising:
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an oscillator circuit including an oscillator, a frequency comparer to compare a frequency of a preset reference signal and a frequency of an oscillation signal based on a preset reference data, the preset reference data corresponding to a target frequency of the oscillation signal, and a Successive-Approximation-Register (SAR) comparer to determine initial control bits to generate an initial frequency according to the comparison result; and a post process module to generate adjacent control bits by changing a value of the initial control bits by one bit, to determine which of the initial frequency and an adjusted frequency corresponding to the adjacent control bits is closer to a target frequency, and to set the closer of the initial frequency and the adjusted frequency as an operating frequency of the oscillator.
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Specification