Phase locked loop circuit responding to supplied signal frequency
First Claim
1. A phase locked loop circuit, said circuit arranged for receiving a first signal having a given frequency and producing a second signal which has the same frequency and is synchronous with the first signal, comprising:
- control voltage generating means for generating a control voltage responding to a phase difference and a frequency difference between the first and second signals;
a voltage controlled oscillator containing a ring oscillator having a multiplicity of quantities of the inverters rows for producing a frequency output which is determined by the control voltage; and
a quantity-of-rows changing means for automatically changing the quantity of the inverters rows in the ring oscillator responding to the control voltage.
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Accused Products
Abstract
A phase locked loop circuit, which is arranged for receiving a first signal having a given frequency and producing a second signal which has the same frequency and is synchronous with the first signal, comprises control voltage generating means for generating a control voltage responding to a phase difference and a frequency difference between the first and second signals, a voltage controlled oscillator containing a ring oscillator having a multiplicity of the rows of inverters for producing a frequency output which is primarily determined by the control voltage, and a quantity-of-rows changing means for automatically changing the quantity of the inverters rows in the ring oscillator according to the control voltage.
48 Citations
18 Claims
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1. A phase locked loop circuit, said circuit arranged for receiving a first signal having a given frequency and producing a second signal which has the same frequency and is synchronous with the first signal, comprising:
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control voltage generating means for generating a control voltage responding to a phase difference and a frequency difference between the first and second signals; a voltage controlled oscillator containing a ring oscillator having a multiplicity of quantities of the inverters rows for producing a frequency output which is determined by the control voltage; and a quantity-of-rows changing means for automatically changing the quantity of the inverters rows in the ring oscillator responding to the control voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A phase locked loop circuit said circuit arranged for receiving a first signal having a given frequency and producing a second signal which has the same frequency and is synchronous with the first signal, comprising:
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control voltage generating means for generating a control voltage responding to a phase difference and a frequency difference between the first and second signals; a voltage controlled oscillator containing a ring oscillator having a multiplicity of quantities of inverters rows for producing a frequency output which is determined by the control voltage; a quantity-of-rows changing means for automatically changing the quantity number of the inverters rows in the ring oscillator responding to the control voltage; a divider for dividing by an integer the second signal supplied to a divided output which is then fed to the phase comparator; said control voltage generating means comprising a phase comparator for producing through comparing the first signal with the second signal fed back from the output a pulse of a phase difference signal between the first and second signals, a charge pump for converting the phase difference signal pulse into a current pulse, and a lowpass filter for converting the current pulse into a DC voltage; said voltage controlled oscillator containing a ring oscillator having an odd number of quantity of inverters rows coupled in cascade for producing the second signal having said frequency when receiving the control voltage; and said quantity of rows selector being arranged for automatically selecting a quantity of the inverters rows in the ring oscillator according to the control voltage.
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17. A phase locked loop circuit, said circuit arranged for receiving a first signal having a given frequency and producing a second signal which has the same frequency and is synchronous with the first signal, comprising:
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control voltage generating means for generating a control voltage responding to a phase difference and a frequency difference between the first and second signals; a voltage controlled oscillator containing a ring oscillator having a multiplicity of the quantities of inverters rows for producing a frequency output which is primarily determined by the control voltage; a quantity-of-rows changing means for automatically changing the quantity of the inverters rows in the ring oscillator responding to the control voltage; a divider for dividing by an integer the second signal supplied to a divided output which is then fed to the phase comparator; said control voltage generating means comprising a phase comparator for producing through comparing the first signal with the second signal fed back from the output a pulse of a phase difference signal between the first and second signals, a charge pump for converting the phase difference signal pulse into a current pulse, and a lowpass filter for converting the current pulse into a DC voltage; said voltage controlled oscillator containing a ring oscillator having an odd number of quantity of inverters rows coupled in cascade for producing the second signal having said frequency when receiving the control voltage; and said quantity of rows selector being arranged for receiving the control voltage and automatically selecting a quantity of the inverters rows in the ring oscillator according to the said frequency by means of feedback of an output from the inverter of a given row in the ring oscillator to the input of the first row of the ring oscillator.
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18. A phase locked loop circuit, said circuit arranged for receiving a first signal having a given frequency and producing a second signal which has the same frequency and is synchronous with the first signal, comprising:
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control voltage generating means for generating a control voltage presenting a phase difference and frequency difference between the first and second signals; a voltage controlled oscillator containing a ring oscillator having a multiplicity of quantities of the inverters rows for producing a frequency output which is determined by the control voltage; a quantity-of-rows changing means for automatically changing the quantity of the inverters rows in the ring oscillator responding to the control voltage; a divider for dividing by an integer the second signal supplied to a divided output which is then fed to the phase comparator; a synchronism detector interposed between the output of the phase comparator and the quantity of inverters rows selector for judging whether synchronization is detected or not upon receiving UP and DOWN signals from the phase comparator and if synchronization is detected, feeding to the quantity of rows selector a stop signal for stopping the change of the quantity of the inverters rows; said control voltage generating means comprising a phase comparator for producing through comparing the first signal with the second signal fed back from the output a pulse of a phase difference signal between the first and second signals, a charge pump for converting the phase difference signal pulse into a current pulse, and a lowpass filter for converting the current pulse into a DC voltage; said voltage controlled oscillator containing a ring oscillator having an odd number of quantity of inverters rows coupled in cascade for producing the second signal having said frequency when receiving the control voltage; and said quantity of inverters rows selector being arranged for receiving the control voltage and automatically selecting a quantity of the inverters rows in the ring oscillator according to said frequency by means of feedback of an output from the inverter of a given row in the ring oscillator to the input of the first row of the ring oscillator.
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Specification