摘要:
In an ADPLL composed of a digital circuit, a technique improving phase difference detection in a vicinity of a phase difference of 0 (zero) is provided. A feedback loop comprises a PFD comparing phases and frequencies of a reference signal and a feedback signal, a TDC converting an output of the PFD into a digital value, a DLF removing a high frequency noise component from an output of the TDC, a DCO controlled based on an output of the DLF and a DIV frequency-dividing an output the DCO and outputting the feedback signal. An offset value is added at any portion of the feedback loop, a phase of the feedback signal is controlled and a value other than 0 is inputted to the TDC even when the ADPLL is locked.
摘要:
In an ADPLL composed of a digital circuit, a technique improving phase difference detection in a vicinity of a phase difference of 0 (zero) is provided. A feedback loop comprises a PFD comparing phases and frequencies of a reference signal and a feedback signal, a TDC converting an output of the PFD into a digital value, a DLF removing a high frequency noise component from an output of the TDC, a DCO controlled based on an output of the DLF and a DIV frequency-dividing an output the DCO and outputting the feedback signal. An offset value is added at any portion of the feedback loop, a phase of the feedback signal is controlled and a value other than 0 is inputted to the TDC even when the ADPLL is locked.
摘要:
A technique for suppressing quantization noise generated due to digitizing an analog circuit in a PLL circuit is provided. The PLL circuit comprises: a digital phase frequency detector which detects (compares) phases and frequencies of a reference signal and a frequency-divided signal and converts the same to a digital value; a digital loop filter which eliminates high-frequency noise components from an output of the digital phase frequency comparator; a digital-analog converter which converts a digital value of an output of the digital loop filter to an analog value; an analog filter which eliminates a high-frequency noise component from an output of the digital-analog converter; a voltage controlled oscillator whose frequency is controlled based on an output of the analog filter; and a frequency divider which divides the frequency of the voltage controlled oscillator and outputs the frequency-divided signal.
摘要:
A semiconductor device includes a controlled oscillator and a control unit. The controlled oscillator includes a resonance circuit, an amplification unit, and a current adjustment unit. The resonance circuit includes one or a plurality of inductors and a first capacitive unit having a variable capacitance value. The amplification unit is connected to the resonance circuit, and outputs a local oscillation signal having an oscillation frequency corresponding to a resonance frequency of the resonance circuit. The current adjustment unit adjusts a value of a drive current to be supplied to the amplification unit. The control unit controls the capacitance value of the first capacitive unit and the current adjustment unit. When the control unit instructs the current adjustment unit to change the value of the drive current to be supplied to the amplification unit, the control unit also changes the capacitance value of the first capacitive unit.
摘要:
To reduce the influence of a spurious in a high-frequency signal processing device and a wireless communication system each provided with a digital type PLL circuit. In a digital type PLL circuit including a digital phase comparator unit, a digital low-pass filter, a digital control oscillator unit, and a multi-module driver unit (frequency divider unit), the clock frequency of a clock signal in the digital phase comparator unit is configured selectably among a plurality of options. The clock frequency is selected among frequencies which are integer multiples of a reference frequency, in accordance with which frequency band of a standard is to be set for an oscillation output signal of the digital control oscillator unit.
摘要:
To reduce the influence of a spurious in a high-frequency signal processing device and a wireless communication system each provided with a digital type PLL circuit. In a digital type PLL circuit including a digital phase comparator unit, a digital low-pass filter, a digital control oscillator unit, and a multi-module driver unit (frequency divider unit), the clock frequency of a clock signal in the digital phase comparator unit is configured selectably among a plurality of options. The clock frequency is selected among frequencies which are integer multiples of a reference frequency, in accordance with which frequency band of a standard is to be set for an oscillation output signal of the digital control oscillator unit.
摘要:
A PLL circuit of which low power consumption and miniaturization are satisfied at the same time is provided. A phase comparator of the PLL circuit includes a counter and a time-to-digital converter. The counter receives a reference clock signal and a low frequency clock signal obtained by dividing an output of a digital controlled oscillator, and a high frequency clock signal. The counter detects a phase difference between the reference clock signal and the low frequency clock signal by counting the clock number of the high frequency clock signal. The time-to-digital converter receives the reference clock signal and the low frequency clock signal. The time-to-digital converter detects the phase difference between the reference clock signal and the low frequency clock signal to the accuracy of a time period shorter than a cycle of the high frequency clock signal, after the output of counter reaches a predetermined range.
摘要:
A PLL circuit of which low power consumption and miniaturization are satisfied at the same time is provided. A phase comparator of the PLL circuit includes a counter and a time-to-digital converter. The counter receives a reference clock signal and a low frequency clock signal obtained by dividing an output of a digital controlled oscillator, and a high frequency clock signal. The counter detects a phase difference between the reference clock signal and the low frequency clock signal by counting the clock number of the high frequency clock signal. The time-to-digital converter receives the reference clock signal and the low frequency clock signal. The time-to-digital converter detects the phase difference between the reference clock signal and the low frequency clock signal to the accuracy of a time period shorter than a cycle of the high frequency clock signal, after the output of counter reaches a predetermined range.
摘要:
A semiconductor device includes a controlled oscillator and a control unit. The controlled oscillator includes a resonance circuit, an amplification unit, and a current adjustment unit. The resonance circuit includes one or a plurality of inductors and a first capacitive unit having a variable capacitance value. The amplification unit is connected to the resonance circuit, and outputs a local oscillation signal having an oscillation frequency corresponding to a resonance frequency of the resonance circuit. The current adjustment unit adjusts a value of a drive current to be supplied to the amplification unit. The control unit controls the capacitance value of the first capacitive unit and the current adjustment unit. When the control unit instructs the current adjustment unit to change the value of the drive current to be supplied to the amplification unit, the control unit also changes the capacitance value of the first capacitive unit.
摘要:
A communication semiconductor integrated circuit device includes an RFVCO and a TXVCO and is formed over one semiconductor substrate, and has a first operation mode (idle mode) which does not perform transmission and reception, a second operation mode (warmup mode) which performs a preparation prior to the start of transmission or reception, and a third operation mode (transmission or reception mode) which performs transmission or reception. In the first operation mode, two oscillators are deactivated, and the operation of selecting a frequency band to be used in at least the TXVCO which generates a transmit signal, is performed in the second operation mode. In the communication semiconductor integrated circuit device, a high frequency signal generator which generates a signal having a desired frequency with an oscillation signal outputted from a crystal oscillator as a reference signal, a reception system circuit (RXC) including a frequency converter, and a transmission system circuit (TXC) including the TXVCO which generates the transmit signal, are respectively formed in different semiconductor regions isolated by insulators.