摘要:
A selection circuit includes a first switching unit that selects and outputs a first signal from among a plurality of analog signals input thereto; a second switching unit that outputs a second signal from a reference voltage supplied therein; and an amplifier that adds the first signal and the second signal.
摘要:
A semiconductor integrated circuit has a plurality of capacitor cells, and each capacitor cell has an upper electrode and a lower electrode. These electrodes are respectively connected to an upper electrode wiring and a lower electrode. When, for example, the upper electrode is connected to the upper electrode wiring and the electrode wiring is located at a side of the lower electrode of another capacitor cell or a side of the lower electrode wiring connecting these electrodes, a shield wiring is provided between the upper electrode wiring and the adjacently-located lower electrode of the other capacitor cell or between the upper electrode wiring and the adjacently-located lower electrode wiring. Thus, with this shield wiring, the capacitance coupling between each wiring of the capacitor cells and each upper electrode or each lower electrode of the capacitor cells are effectively suppressed.
摘要:
A PLL circuit comprises a frequency comparator for detecting a phase difference based on a difference in frequencies between a reproduced data pulse and a clock generated by a VCO; a phase comparator for detecting a difference in phases between the reproduced data pulse and the VCO clock; a selector for selectively outputting a signal supplied from the frequency comparator; a first charge pump for increasing/decreasing the output voltage on the basis of the output from the selector; a second charge pump for increasing/decreasing the output voltage on the basis of the output from the phase comparator; a loop filter for eliminating unnecessary components included in a signal obtained by adding the output from the first charge pump and the output from the second charge pump; and a VCO for generating a clock of a frequency corresponding to the output voltage of the loop filter. In this PLL circuit, when the phase difference between the reproduced data pulse and the VCO clock is within the pull-in range of the phase comparator, the operation of the frequency comparator is restricted by the output of the phase comparator. Therefore, the PLL circuit can perform stable data reading even when the reproduced data pulse has a large amount of clock jitter.
摘要:
To provide a D/A conversion apparatus that can minimize the increase in the amount of circuitry if the number of output levels is increased, a digital input value, input for each sampling clock, is first converted by a digital filter and a noise shaper into a word length limited digital signal with a high sampling frequency. The output of the noise shaper is mapped by a decoder to n m-valued signals a “1” at a time in a cyclic fashion progressing from one signal to the next so that the sum of the n m-valued signals becomes equal to the digital input value; thereafter, the n m-valued signals are converted by n m-valued D/A converters into corresponding analog signals which are then summed together by an analog adder to produce an analog output signal. The term “cyclic” means not only that one digital input value is mapped to the n m-valued signals a “1” at a time in a cyclic fashion progressing from one signal to the next, but also that the mapping of the present digital input value to the n m-valued signals is performed starting with the m-valued signal that immediately follows the m-valued signal to which the preceding digital input value was last mapped.
摘要:
A semiconductor integrated circuit has a plurality of capacitor cells, and each capacitor cell has an upper electrode and a lower electrode. These electrodes are respectively connected to an upper electrode wiring and a lower electrode. When, for example, the upper electrode is connected to the upper electrode wiring and the electrode wiring is located at a side of the lower electrode of another capacitor cell or a side of the lower electrode wiring connecting these electrodes, a shield wiring is provided between the upper electrode wiring and the adjacently-located lower electrode of the other capacitor cell or between the upper electrode wiring and the adjacently-located lower electrode wiring. Thus, with this shield wiring, the capacitance coupling between each wiring of the capacitor cells and each upper electrode or each lower electrode of the capacitor cells are effectively suppressed.
摘要:
A PLL circuit comprises a frequency comparator for detecting a phase difference based on a difference in frequencies between a reproduced data pulse and a clock generated by a VCO; a phase comparator for detecting a difference in phases between the reproduced data pulse and the VCO clock; a selector for selectively outputting a signal supplied from the frequency comparator, a first charge pump for increasing/decreasing the output voltage on the basis of the output from the selector; a second charge pump for increasing/decreasing the output voltage on the basis of the output from the phase comparator; a loop filter for eliminating unnecessary components included in a signal obtained by adding the output from the first charge pump and the output from the second charge pump; and a VCO for generating a clock of a frequency corresponding to the output voltage of the loop filter. In this PLL circuit, when the phase difference between the reproduced data pulse and the VCO clock is within the pull-in range of the phase comparator, the operation of the frequency comparator is restricted by the output of the phase comparator. Therefore, the PLL circuit can perform stable data reading even when the reproduced data pulse has a large amount of clock jitter.
摘要:
A semiconductor integrated circuit has a plurality of capacitor cells, and each capacitor cell has an upper electrode and a lower electrode. These electrodes are respectively connected to an upper electrode wiring and a lower electrode. When, for example, the upper electrode is connected to the upper electrode wiring and the electrode wiring is located at a side of the lower electrode of another capacitor cell or a side of the lower electrode wiring connecting these electrodes, a shield wiring is provided between the upper electrode wiring and the adjacently-located lower electrode of the other capacitor cell or between the upper electrode wiring and the adjacently-located lower electrode wiring. Thus, with this shield wiring, the capacitance coupling between each wiring of the capacitor cells and each upper electrode or each lower electrode of the capacitor cells are effectively suppressed.
摘要:
A PLL circuit comprises a frequency comparator for detecting a phase difference based on a difference in frequencies between a reproduced data pulse and a clock generated by a VCO; a phase comparator for detecting a difference in phases between the reproduced data pulse and the VCO clock; a selector for selectively outputting a signal supplied from the frequency comparator; a first charge pump for increasing/decreasing the output voltage on the basis of the output from the selector; a second charge pump for increasing/decreasing the output voltage on the basis of the output from the phase comparator; a loop filter for eliminating unnecessary components included in a signal obtained by adding the output from the first charge pump and the output from the second charge pump; and a VCO for generating a clock of a frequency corresponding to the output voltage of the loop filter. In this PLL circuit, when the phase difference between the reproduced data pulse and the VCO clock is within the pull-in range of the phase comparator, the operation of the frequency comparator is restricted by the output of the phase comparator. Therefore, the PLL circuit can perform stable data reading even when the reproduced data pulse has a large amount of clock jitter.
摘要:
In a charge redistribution type A/D converter, an input-side capacitor terminal and a comparator-side capacitor terminal are connected through first and second analog switches to a fixed-voltage supply circuit, and the input-side capacitor terminal is connected through a third analog switch to the outside. Immediately before sampling an analog signal, the first and second analog switches are closed while the third analog switch is opened, according to a RESET signal. Thereby, fixed voltages are supplied to the input-side capacitor terminal and the comparator-side capacitor terminal, respectively, and charge stored in a weighting capacitor unit is initialized to a predetermined value.
摘要:
A differential output circuit which performs data transmission by means of a differential current comprises: a first current source for outputting an electric current to the outside of the circuit; a second current source for introducing an electric current from the outside of the circuit; an output polarity switching circuit for switching the polarity of the differential current generated by the first and second current sources; a voltage source for supplying a predetermined voltage; and a resistor connected between a predetermined node and the voltage source, the predetermined node being interposed between the first and second current sources.