Communication semiconductor integrated circuit device
First Claim
1. A communication semiconductor integrated circuit device comprising:
- a phase control loop including a transmission oscillator that outputs a phase modulated signal, being configured to be capable of an oscillation operation in plural frequency bands, a phase comparator that compares a phase of an output signal from the transmission oscillator and a phase of a phase modulated and amplitude modulated signal, and a charge pump that generates a voltage according to an output of the phase comparator, the phase control loop that controlling an oscillation frequency of the transmission oscillator based on the voltage generated by the charge pump; and
an amplitude control loop including an amplitude comparator that compares an amplitude of an output signal from a power amplifier amplifying a power of a transmission signal and an amplitude of a phase modulated and amplitude modulated signal, the amplitude control loop generating a voltage according to an amplitude difference detected by the amplitude comparator and outputting the voltage to the power amplifier as an output level control signal, wherein a deviation of a control voltage vs. oscillation frequency characteristic of the transmission oscillator is corrected by calibrating a current of the charge pump.
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Abstract
The invention provides a communication semiconductor integrated circuit (RF IC) that, when a transmission oscillator is incorporated into a semiconductor chip, secures the oscillation operation over a wide frequency range, prevents a deterioration of a transmission spectrum, and thereby enhances the accuracy of an oscillation frequency. The integrated circuit corrects a dispersion of the KV characteristic of the transmission oscillator by calibrating a current Icp of the charge pump inside the phase control loop. More in concrete, the integrated circuit measures a KV value Kv of the transmission oscillator, and calibrates the current Icp of the charge pump so that Kv·Icp falls into a predetermined value.
65 Citations
10 Claims
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1. A communication semiconductor integrated circuit device comprising:
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a phase control loop including a transmission oscillator that outputs a phase modulated signal, being configured to be capable of an oscillation operation in plural frequency bands, a phase comparator that compares a phase of an output signal from the transmission oscillator and a phase of a phase modulated and amplitude modulated signal, and a charge pump that generates a voltage according to an output of the phase comparator, the phase control loop that controlling an oscillation frequency of the transmission oscillator based on the voltage generated by the charge pump; and
an amplitude control loop including an amplitude comparator that compares an amplitude of an output signal from a power amplifier amplifying a power of a transmission signal and an amplitude of a phase modulated and amplitude modulated signal, the amplitude control loop generating a voltage according to an amplitude difference detected by the amplitude comparator and outputting the voltage to the power amplifier as an output level control signal, wherein a deviation of a control voltage vs. oscillation frequency characteristic of the transmission oscillator is corrected by calibrating a current of the charge pump. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification