Voltage controlled oscillator circuit, phase-locked loop circuit using the voltage controlled oscillator circuit, and semiconductor device provided with the same
First Claim
1. A voltage controlled oscillator circuit comprising:
- a control portion to which a first voltage is inputted and from which a second voltage corresponding to the first voltage is outputted;
a current source portion to which the second voltage is inputted and from which a current corresponding to the second voltage is outputted; and
an oscillator circuit to which the current is inputted and from which a signal with a frequency in accordance with the current is outputted,wherein the control portion includes an adjusting circuit,wherein the adjusting circuit changes the second voltage in accordance with change of a power supply voltage,wherein the control portion includes a first transistor, a second transistor, and a third transistor connected in series with the first transistor,wherein the adjusting circuit includes the second transistor,wherein the third transistor is diode-connected,wherein a drain current of the third transistor is the sum of a drain current of the first transistor and a drain current of the second transistor,wherein the first voltage is inputted to a gate of the first transistor,wherein the second voltage is outputted from a drain of the first transistor,wherein a third voltage is inputted to a gate of the second transistor,wherein the third voltage changes in accordance with chance of the power supply voltage,wherein both of the first transistor and the second transistor are n-channel transistors, andwherein the third voltage decreases when the power supply voltage is increased, whereas the third voltage increases when the power supply voltage is decreased.
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Accused Products
Abstract
A VCO circuit includes: a control portion to which a first voltage is inputted and from which a second voltage corresponding to the first voltage is outputted; a current source portion to which the second voltage is inputted and from which a current corresponding to the second voltage is outputted; and an oscillator circuit to which the current is inputted and from which a signal with a frequency in accordance with the current is outputted. The control portion includes an adjusting circuit which changes the second voltage in conjunction with fluctuation of a power supply voltage. Accordingly, fluctuation of the frequency Fo of an output signal of the VCO circuit can be suppressed even when the power supply voltage of the VCO circuit fluctuates.
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Citations
35 Claims
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1. A voltage controlled oscillator circuit comprising:
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a control portion to which a first voltage is inputted and from which a second voltage corresponding to the first voltage is outputted; a current source portion to which the second voltage is inputted and from which a current corresponding to the second voltage is outputted; and an oscillator circuit to which the current is inputted and from which a signal with a frequency in accordance with the current is outputted, wherein the control portion includes an adjusting circuit, wherein the adjusting circuit changes the second voltage in accordance with change of a power supply voltage, wherein the control portion includes a first transistor, a second transistor, and a third transistor connected in series with the first transistor, wherein the adjusting circuit includes the second transistor, wherein the third transistor is diode-connected, wherein a drain current of the third transistor is the sum of a drain current of the first transistor and a drain current of the second transistor, wherein the first voltage is inputted to a gate of the first transistor, wherein the second voltage is outputted from a drain of the first transistor, wherein a third voltage is inputted to a gate of the second transistor, wherein the third voltage changes in accordance with chance of the power supply voltage, wherein both of the first transistor and the second transistor are n-channel transistors, and wherein the third voltage decreases when the power supply voltage is increased, whereas the third voltage increases when the power supply voltage is decreased. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. The voltage controlled oscillator circuit comprising:
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a control portion to which a first voltage is inputted and from which a second voltage corresponding to the first voltage is outputted; a current source portion to which the second voltage is inputted and from which a current corresponding to the second voltage is outputted; and an oscillator circuit to which the current is inputted and from which a signal with a frequency in accordance with the current is outputted, wherein the control portion includes an adjusting circuit, wherein the adjusting circuit changes the second voltage in accordance with change of a power supply voltage, wherein the control portion includes a first transistor, a second transistor, and a third transistor connected in series with the first transistor, wherein the adjusting circuit includes the second transistor, wherein the third transistor is diode-connected, wherein a drain current of the third transistor is the sum of a drain current of the first transistor and a drain current of the second transistor, wherein the first voltage is inputted to a gate of the first transistor, wherein the second voltage is outputted from a drain of the first transistor, wherein a third voltage is inputted to a gate of the second transistor, wherein the third voltage changes in accordance with change of the power supply voltage, and wherein the third voltage changes so as to decrease the drain current of the second transistor when the power supply voltage is increased, whereas the third voltage changes so as to increase the drain current of the second transistor when the power supply voltage is decreased. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. The voltage controlled oscillator circuit comprising:
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a control portion to which a first voltage is inputted and from which a second voltage corresponding to the first voltage is outputted; a current source portion to which the second voltage is inputted and from which a current corresponding to the second voltage is outputted; and an oscillator circuit to which the current is inputted and from which a signal with a frequency in accordance with the current is outputted, wherein the control portion includes an adjusting circuit, wherein the adjusting circuit changes the second voltage in accordance with change of a power supply voltage, wherein the control portion includes a first transistor, a second transistor, a third transistor connected in series with the first transistor, a fourth transistor, and a fifth transistor connected in series with the fourth transistor, wherein the adjusting circuit includes the second transistor, wherein the third transistor is diode-connected, wherein the fifth transistor is diode-connected, wherein the first transistor and the fifth transistor form a current mirror circuit, wherein a drain current of the third transistor is the sum of a drain current of the first transistor and a drain current of the second transistor, wherein the first voltage is inputted to a gate of the fourth transistor, wherein the second voltage is outputted from a drain of the first transistor, wherein a third voltage is inputted to a gate of the second transistor, and wherein the third voltage changes in conjunction with fluctuation of the power supply voltage. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A voltage controlled oscillator circuit comprising:
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a control portion to which a first voltage is inputted and from which a second voltage corresponding to the first voltage is outputted; a current source portion to which the second voltage is inputted and from which a current corresponding to the second voltage is outputted; and an oscillator circuit to which the current is inputted and from which a signal with a frequency in accordance with the current is outputted, wherein the control portion includes a first transistor, a second transistor, a third transistor which is diode-connected, and a monitor circuit, wherein the first voltage is inputted to a gate of the first transistor, wherein the second voltage is outputted from a drain of the first transistor, wherein a third voltage is inputted to a gate of the second transistor, wherein a drain of the third transistor is connected to the drain of the first transistor and a drain of the second transistor, wherein a source of the first transistor is connected to a source of the second transistor, wherein the monitor circuit includes a fourth transistor which is diode-connected, a fifth transistor which is diode-connected, a sixth transistor which is diode-connected, and a seventh transistor, wherein a gate of the fourth transistor and a gate of the fifth transistor are connected to a gate of the seventh transistor, and wherein the third voltage is outputted from a drain of the seventh transistor. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35)
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Specification