摘要:
Each of n signal transition detection sections detects a transition of the signal level of at least one of a first input signal or a second input signal corresponding to the signal transition detection section. A time-division control section outputs a control pulse according to a system clock when a signal transition is detected by at least one of the n signal transition detection sections. Each of n output switching sections outputs either the first or the second input signal corresponding to the output switching section as a multiplexed signal according to the control pulse.
摘要:
Each of n signal transition detection sections detects a transition of the signal level of at least one of a first input signal or a second input signal corresponding to the signal transition detection section. A time-division control section outputs a control pulse according to a system clock when a signal transition is detected by at least one of the n signal transition detection sections. Each of n output switching sections outputs either the first or the second input signal corresponding to the output switching section as a multiplexed signal according to the control pulse.
摘要:
A variable delay circuit successively delays an input clock to generate a plurality of delayed clocks having different phases. A phase comparison circuit receives a first reference clock, which is either one of the delayed clocks or the input clock, and a second reference clock, which is one of the delayed clocks and whose phase lags behind that of the first reference clock, specifies a validated interval for the second reference clock, and compares the phases of the first and second reference clocks according to voltage levels of the first and second reference clocks only during the validated interval. A delay control circuit controls a delay time in the variable delay circuit according to a result of the comparison obtained by the phase comparison circuit.
摘要:
There is provided a spike noise eliminating circuit that can eliminate reliably spike noise having a predetermined pulse width or smaller and transmit and output precisely a signal having a pulse width larger than the predetermined width. Spike noise in the input signal is eliminated by: detecting a coincidence in level of the input signal and a first delay signal obtained by delaying the input signal by a maximum pulse width of noise to be eliminated as a delay amount; and sampling the input signal or a second delay signal obtained by delaying the input signal by a certain period of time based on a signal obtained as a result of detecting the coincidence in level.
摘要:
A PLL circuit that makes a voltage-controlled oscillator converge to a stable state within a short time and generates a clock signal with high stability even when discontinuity occurs in the period of a reference input signal is provided. The PLL circuit has a voltage-controlled oscillator for outputting a clock controlled, a first counter reset by the reference input signal having one period longer than a reference period within a predetermined period for outputting a first signal, a second counter for outputting a second signal, a reset pulse generating circuit for resetting the second counter, a loop filter for holding and outputting the control voltage varied by a phase error signal and a discontinuous input detecting part for detecting the reference input signal input initially after its period becomes longer than the reference period.
摘要:
The present invention provides a PLL circuit that makes a voltage-controlled oscillator converge to a stable state within a short time and generates a clock signal with high stability even when discontinuity occurs in the period of a reference input signal. The PLL circuit of the present invention has a voltage-controlled oscillator for outputting a clock controlled, a first counter reset by the reference input signal having one period longer than a reference period within a predetermined period for outputting a first signal, a second counter for outputting a second signal, a reset pulse generating circuit for resetting the second counter, a loop filter for holding and outputting the control voltage varied by a phase error signal and a discontinuous input detecting part for detecting the reference input signal input initially after its period becomes longer than the reference period.
摘要:
A PLL lock detection circuit produces a high precision PLL lock detection signal and enables eliminating a smoothing circuit. The PLL lock detection circuit reliably detects if the PLL circuit is locked reliably and without error by simultaneously evaluating both locked and unlocked states. A continuity detection unit detects if a PLL locked state continues for H consecutive periods, and another continuity detection unit detects if a PLL unlocked state continues for H consecutive periods. The continuity detection units simultaneously output the PLL locked/unlocked states, and an R-S latch holds the detection result.
摘要:
A power-on reset circuit of the present invention comprises: a first p-channel MOS transistor having the gate and the drain which are grounded and having a substrate which is connected to a power supply; a first resistor which is inserted and connected between the above-mentioned power supply and the source of the above-mentioned first p-channel MOS transistor; a first inverter having an input terminal which is connected to the source of the first p-channel MOS transistor; and a power-on reset signal output terminal which is connected to an output terminal of the first inverter.
摘要:
The digital-analog converter circuit includes: a high-order D-A converter circuit unit (100) for outputting a first voltage (Va) and a second voltage (Vb) both resulting from D-A conversion of the high-order five bits of a 13-bit input code to first and second output nodes (11, 12) through two buffers (10a, 10b) having the same characteristics, respectively; a low-order D-A converter circuit unit (200) for receiving the voltages on these two output nodes as reference voltages of an R-2R ladder circuit (201) and conducting D-A conversion of the low-order eight bits of the input code for output to a third output node (13); a sample-and-hold unit (250) for selectively sampling and holding the voltage on the third output node (13), i.e., the D-A conversion output of the 13-bit input code, according to a value of the input code; and an output unit (300) for multiplying the sampled and held D-A conversion output voltage by a gain with respect to an arbitrary central voltage. Thus, a D-A converter circuit capable of outputting a desired analog voltage with high accuracy even when a large number of bits are converted is implemented with a small chip area.
摘要:
There is provided a spike noise eliminating circuit that can eliminate reliably spike noise having a predetermined pulse width or smaller and transmit and output precisely a signal having a pulse width larger than the predetermined width. Spike noise in the input signal is eliminated by: detecting a coincidence in level of the input signal and a first delay signal obtained by delaying the input signal by a maximum pulse width of noise to be eliminated as a delay amount; and sampling the input signal or a second delay signal obtained by delaying the input signal by a certain period of time based on a signal obtained as a result of detecting the coincidence in level.