SEMICONDUCTOR DEVICE AND PLL CIRCUIT
First Claim
1. A semiconductor device comprising a phase locked loop circuit, wherein the phase locked loop circuit comprises:
- a proportional path provided in a first power supply system and configured to output an analog proportional signal according to a detection signal, the detection signal indicating a phase difference between a reference signal and a signal obtained by feeding back an output signal of the phase locked loop circuit;
an integral path provided in a second power supply system and configured to output an analog integral signal according to the detection signal, a voltage of the second power supply system being lower than that of the first power supply system;
a current-controlled oscillator driver provided in the first power supply system and configured to output control current according to the analog proportional signal from the proportional path and the analog integral signal from the integral path;
a current-controlled oscillator provided in the second power supply system and configured to output an output signal generated by performing an oscillation operation according to the control current; and
a phase frequency detector provided in the second power supply system and configured to detect a phase difference between the reference signal and the signal obtained by feeding back the output signal and then output a result of the detection as the detection signal.
1 Assignment
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Accused Products
Abstract
An object is to improve Power Supply Rejection Ratio in a PLL circuit. A proportional path 103 is provided in a first power supply system 101 and outputs analog proportional signal AP according to a detection signal DET. An integral path 104 is provided in a second power supply system and outputs an analog integral signal AI according to the DET. A CCO driver 16 is provided in the first power supply system 101 and outputs control current ICCO according to the AP and the AI. A CCO 17 is provided in the second power supply system 102 and outputs an output signal Fout according to the ICCO. A phase frequency detector 11 is provided in the second power supply system 102 and configured to detect a phase difference between a reference signal Fref and a signal FM obtained by feeding back the Fout and then outputs the DET.
8 Citations
12 Claims
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1. A semiconductor device comprising a phase locked loop circuit, wherein the phase locked loop circuit comprises:
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a proportional path provided in a first power supply system and configured to output an analog proportional signal according to a detection signal, the detection signal indicating a phase difference between a reference signal and a signal obtained by feeding back an output signal of the phase locked loop circuit; an integral path provided in a second power supply system and configured to output an analog integral signal according to the detection signal, a voltage of the second power supply system being lower than that of the first power supply system; a current-controlled oscillator driver provided in the first power supply system and configured to output control current according to the analog proportional signal from the proportional path and the analog integral signal from the integral path; a current-controlled oscillator provided in the second power supply system and configured to output an output signal generated by performing an oscillation operation according to the control current; and a phase frequency detector provided in the second power supply system and configured to detect a phase difference between the reference signal and the signal obtained by feeding back the output signal and then output a result of the detection as the detection signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification