Abstract:
An apparatus includes a phase-locked loop and a jitter detection circuit. A method of detecting a jitter in the apparatus includes the phase-locked loop generating a lead control signal and a lag control signal according to a reference clock and a feedback clock, the jitter detection circuit generating a jitter signal according to the lead control signal and the lag control signal, the jitter detection circuit generating a jitter window signal according to the jitter signal, the jitter detection circuit identifying jitters in the clock signal according to the jitter signal and the jitter window signal, and the jitter detection circuit outputting a jitter indication signal according to the number of jitters identified.
Abstract:
A circuit and a method for restarting up a VCO of a PLL are introduced herein. The VCO restart up circuit receives a power down signal, an external signal, a clock output from the VCO and generates a trigger signal to the VCO to trigger the VCO clock to leave a stable mode. In other words, if the VCO clock is in the stable mode, the VCO restart up circuit generates one or more than one pulse on a trigger signal to restart up the VCO. Oppositely, if the VCO is not in the stable mode, there is no pulse on the trigger signal generated by the VCO restart up circuit and the VCO needs not to be restarted up.
Abstract:
An asynchronous successive approximation register analog-to-digital converter includes a clock generator, a logic control unit, a sample and hold circuit, a digital-to-analog converter and a comparator. The clock generator is used to generate a clock signal. The logic control unit is for generating a sample and hold clock according to the clock signal. The sample and hold circuit is for sampling an analog signal according to the sample and hold clock to obtain and hold a sampling signal. The digital-to-analog converter is for generating a reference value according to a digital value transmitted from the logic control unit. The comparator is for generating a comparison value according to the sampling signal and the reference value.
Abstract:
A SAR ADC includes: a sample-hold (S/H) circuit sampling an input voltage to generate a S/H output signal; a DAC generating a DAC output signal; a comparator comparing the DAC output signal with the S/H output signal to generate a comparison output signal; a SAR combinational digital circuit group; a multiplexer circuit; and a plurality of registers for registering the comparison output signal as register output signals and outputting as an output signal of the SAR ADC. The SAR combinational digital circuit group generates a plurality of first and second SAR output signals based on the register output signals. The multiplexer circuit is controlled by on the register output signals to select among the first and the second SAR output signals as a plurality of multiplexer output signals for sending to the DAC. A capacitor coupling relationship of the DAC is controlled by the multiplexer output signals.
Abstract:
A circuit and a method for restarting up a VCO of a PLL are introduced herein. The VCO restart up circuit receives a power down signal, an external signal, a clock output from the VCO and generates a trigger signal to the VCO to trigger the VCO clock to leave a stable mode. In other words, if the VCO clock is in the stable mode, the VCO restart up circuit generates one or more than one pulse on a trigger signal to restart up the VCO. Oppositely, if the VCO is not in the stable mode, there is no pulse on the trigger signal generated by the VCO restart up circuit and the VCO needs not to be restarted up.
Abstract:
According to an aspect of the disclosure, the disclosure provides an ADC which includes not limited to: a DAC configured to generate a positive input delta voltage and a negative input delta voltage, a comparator electrically connected to the DAC and configured to receive the positive input delta voltage to generate a first digital output value and to receive the negative input delta voltage to generate a second digital output value, a logic circuit configured to receive, from the comparator, the first digital output value and the second digital output value to generate a digital quantization code according to half of a sum of the first digital output value and the second digital output value, and a calibration circuit configured to receive the digital quantization code from the logic circuit and calibrate an output of the ADC according to the digital quantization code to eliminate an offset error value.
Abstract:
A phase-locked loop (PLL) and a method for controlling the PLL are provided. The PLL includes a phase detector, a charge pump, a voltage-controlled oscillator (VCO), a feedback frequency divider, and a detector circuit. The phase detector generates a direction signal according to a comparison between phases of a first clock signal and a second clock signal. The charge pump converts the direction signal into a control voltage. The VCO generates a third clock signal. The control voltage controls a frequency of the third clock signal. The feedback frequency divider divides the frequency of the third clock signal to generate the second clock signal. The detector circuit sends a pulse signal to restart the VCO when the control voltage conforms to a preset condition.
Abstract:
A digital-to-analog converter includes a clock driver, a first decoder, a second decoder, a current source matrix, a pseudo random mode generator and at least one multiplexer. The first decoder and the second decoder are coupled to the clock driver. The current source matrix is coupled to the first decoder, and the pseudo random mode generator is used to randomly output a set of selecting signals. Each multiplexer of the at least one multiplexer includes a plurality of input ends coupled to a plurality of output ends of the second decoder, an output end coupled to the current source matrix, and a select end coupled to the pseudo random mode generator for controlling the output end to output a bit signal inputted from the input ends of the multiplexer according to one selecting signal of the set of selecting signals.