Abstract: A receiver circuit which can suppress a voltage amplitude appearing on a transmission line. The receiver circuit, coupled to a first and a second transmission lines which transmit information by using currents, includes a first and a second current sources, a first and a second conversion sections which convert currents which flow respectively therein to voltages, a first transistor whose source is coupled to the first current source and to the first transmission line, and whose drain is coupled to the first conversion section, and a second transistor whose source is coupled to the second current source and to the second transmission line, and whose drain is coupled to the second conversion section. The gate and the drain of the first transistor are respectively coupled to the drain and the gate of the second transistor.

Abstract: A phase comparison process in a timing recovery process for high-speed data communication defines a data window and compares the phase of a clock in the window with the phase of an edge of data so as to realize a parallel process, wherein the phase comparison and the process of determining whether a data edge lies within the window are performed in parallel to each other, and the phase comparison result is output only if the data edge lies within the window. With this configuration, it is possible to perform an accurate phase comparison process with no errors without requiring high-precision delay circuits.

Abstract: A phase control device that adjusts a phase of a clock receives a first clock, a second clock and a control code. The phase control device includes phase adjusters (PI-11, PI-12), PI-2 and PI-3 that output a clock of a phase corresponding to the control code. These phase adjusters are connected in a three-stages cascade. The control codes of these phase adjusters (PI-11, PI-12), PI-2 and PI-3 are varied in association with each other. Therefore, as compared with a case where a phase of a clock is adjusted by a phase adjuster alone, if a resolution (adjustment granularity) of each phase adjuster is defined as N, it is possible to reduce the adjustment granularity of a phase as small as N to the power of the number of the stages. Therefore, when the phase control device is used for a SSC, the peak power reduction value is improved.

Abstract: A receiver circuit which can suppress a voltage amplitude appearing on a transmission line. The receiver circuit, coupled to a first and a second transmission lines which transmit information by using currents, includes a first and a second current sources, a first and a second conversion sections which convert currents which flow respectively therein to voltages, a first transistor whose source is coupled to the first current source and to the first transmission line, and whose drain is coupled to the first conversion section, and a second transistor whose source is coupled to the second current source and to the second transmission line, and whose drain is coupled to the second conversion section. The gate and the drain of the first transistor are respectively coupled to the drain and the gate of the second transistor.

Abstract: In a receiver circuit that receives data and clock signals through the cables, the number of transitions of a signal obtained based on the data or clock signal is detected by a frequency detection circuit, and when the number of transitions is not more than a predetermined set value, a signal for resetting the operation of a serial-parallel converter circuit included in a data processing unit is output, so as to control the output of received data. Thus, disconnection of the cable can be detected with low power consumption without providing a pull-up resistor and pull-down resistor and noise resistance can be improved.

Abstract: A phase comparison process in a timing recovery process for high-speed data communication defines a data window and compares the phase of a clock in the window with the phase of an edge of data so as to realize a parallel process, wherein the phase comparison and the process of determining whether a data edge lies within the window are performed in parallel to each other, and the phase comparison result is output only if the data edge lies within the window. With this configuration, it is possible to perform an accurate phase comparison process with no errors without requiring high-precision delay circuits.

Abstract: A resynchronization circuit possesses a sufficient migration margin even when the speed of a clock signal used for outputting data is increased, so that the data transfer speed can be increased. In the resynchronization circuit, a determination circuit holds a signal which is determined according to the phase difference between a determination signal and a reference clock signal (determination result). In a synchronization circuit block, a received data signal is held in synchronization with a strobe signal. Then, the received data signal is held in synchronization with a clock signal which has the same frequency as that of the reference clock signal and has a phase determined according to the determination result and output from the resynchronization circuit.

Abstract: In a receiver circuit that receives data and clock signals through the cables, the number of transitions of a signal obtained based on the data or clock signal is detected by a frequency detection circuit, and when the number of transitions is not more than a predetermined set value, a signal for resetting the operation of a serial-parallel converter circuit included in a data processing unit is output, so as to control the output of received data. Thus, disconnection of the cable can be detected with low power consumption without providing a pull-up resistor and pull-down resistor and noise resistance can be improved.

Abstract: In a receiver circuit that receives data and clock signals through the cables, the number of transitions of a signal obtained based on the data or clock signal is detected by a frequency detection circuit, and when the number of transitions is not more than a predetermined set value, a signal for resetting the operation of a serial-parallel converter circuit included in a data processing unit is output, so as to control the output of received data. Thus, disconnection of the cable can be detected with low power consumption without providing a pull-up resistor and pull-down resistor and noise resistance can be improved.

Abstract: The first data transmitting/receiving device according to the present invention includes: a serial-parallel conversion circuit for converting received first serial data to first parallel data; a data selection circuit for selecting any one of the first parallel data and externally-supplied second parallel data and outputting the selected data; and a parallel-serial conversion circuit for converting the first or second parallel data output from the data selection circuit to second serial data which is to be transmitted.

Abstract: A circuit for detecting whether an intermittent clock waveform signal of 50 MHz is received or not includes an offset receiver, a charge pump, a capacitor and a hysteresis comparator. A circuit for detecting whether a random data waveform signal of 500 MHz is received or not includes an offset-less receiver, a transition counter, a delay circuit and an AND circuit. An OR circuit outputs as a signal detection signal a signal indicating the OR operation result of respective outputs of the hysteresis comparator and the AND circuit.

Abstract: The frequency modulation circuit includes: a phase shift section for receiving a multiphase clock signal composed of a plurality of clock signals having a predetermined phase difference therebetween and shifting the phase of the multiphase clock signal; a clock selection section for selecting a clock signal constituting the multiphase clock signal output from the phase shift section; and a modulation control section for controlling the phase shift section and the clock selection section so that a clock signal having a frequency different from the frequency of the multiphase clock signal input into the phase shift section is output from the clock selection section.

Abstract: In a receiver circuit that receives data and clock signals through the cables, the number of transitions of a signal obtained based on the data or clock signal is detected by a frequency detection circuit, and when the number of transitions is not more than a predetermined set value, a signal for resetting the operation of a serial-parallel converter circuit included in a data processing unit is output, so as to control the output of received data. Thus, disconnection of the cable can be detected with low power consumption without providing a pull-up resistor and pull-down resistor and noise resistance can be improved.

Abstract: A driver and a receiver supply a data signal, which is based on serial data having a regular bit pattern, such as a clock, which includes 1's and 0's alternating with each other during an adjustment period, and is based on serial data having an arbitrary bit pattern during a transfer period following the adjustment period. A duty factor controller adjusts a data transition characteristic of the driver or the receiver so that a duty factor of the data signal supplied from the receiver is equal to 50% in the adjustment period, and has the adjusted data transition characteristic stored. A clock recovery unit recovers a clock synchronized with a data signal, which is supplied from the receiver in the transfer period and is based on the adjusted transition characteristic, from the data signal.

Abstract: In a receiver circuit that receives data and clock signals through the cables, the number of transitions of a signal obtained based on the data or clock signal is detected by a frequency detection circuit, and when the number of transitions is not more than a predetermined set value, a signal for resetting the operation of a serial-parallel converter circuit included in a data processing unit is output, so as to control the output of received data. Thus, disconnection of the cable can be detected with low power consumption without providing a pull-up resistor and pull-down resistor and noise resistance can be improved.

Abstract: An input circuit includes: a comparator; first and second delay circuits; a selector; an input buffer; and a holding circuit. The comparator compares the leading and/or trailing edges of a data signal, supplied from the input buffer, to an edge of a clock signal on which the data signal is intended to be latched. Based on the results of the comparison, the first and second delay circuits delay the clock signal for respectively predetermined amounts of time. If the data signal is logically high, then the selector selects a delayed clock signal supplied from the first delay circuit. Alternatively, if the data signal is logically low, then the selector selects another delayed clock signal supplied from the second delay circuit. Then, the delayed clock signal, selected by the selector, is latched in the holding circuit.

Abstract: A driver and a receiver supply a data signal, which is based on serial data having a regular bit pattern, such as a clock, which includes 1's and 0's alternating with each other during an adjustment period, and is based on serial data having an arbitrary bit pattern during a transfer period following the adjustment period. A duty factor controller adjusts a data transition characteristic of the driver or the receiver so that a duty factor of the data signal supplied from the receiver is equal to 50% in the adjustment period, and has the adjusted data transition characteristic stored. A clock recovery unit recovers a clock synchronized with a data signal, which is supplied from the receiver in the transfer period and is based on the adjusted transition characteristic, from the data signal.

Abstract: To a data reception device, a signal having a frequency of 12.5 MHz and including data is transmitted. The data reception device generates a clock B having a frequency of 400 MHz of (1) in FIG. 8, and performs sampling for the above-described 12.5 MHz signal based on the clock B ((2) in FIG. 8). Then, the data reception device detects zero cross points of the sampled data, and generates a 25 MHz frequency clock signal indicating the zero cross points ((3) in FIG. 8). Next, the data reception device generates, by delaying the generated clock signal by the time amount corresponding to eight clocks ((4) in FIG. 8), a 25 MHz signal indicating symbol points. Thus, symbol points can be detected.

Abstract: The invention provides a low-pass filter suitably used as a loop filter for a PLL or a DLL that has a filtering characteristic equivalent to that of a conventional one and can be realized in a smaller circuit area. The low-pass filter includes first filtering means (31) for accepting, as an input, an input signal to the low-pass filter and outputting a first voltage; a circuit element (311) included in the first filtering means (31) for allowing a first current to flow in accordance with the first voltage; current generating means (32) for generating a second current at a given rate to the first current; second filtering means (33) for accepting, as an input, the second current and outputting a second voltage; and adding means (34) for adding the first voltage and the second voltage and outputting an output signal of the low-pass filter, in which the second current is set to be smaller than the first current.

Abstract: The driver circuit of the present invention includes: a drive section for generating a differential signal according to an input signal and outputting the signal to an electric cable or an optical transceiver; and a control section receiving a selection signal based on which the drive section selects to drive the electric cable or the optical transceiver, an identification signal, and a data signal, for generating a signal based on the received signals and outputting the generated signal to the drive section. During a period indicated by the identification signal, the control section controls the drive section to put the output of the drive section in a high impedance state when the selection signal indicates selection of the electric cable, or output a predetermined differential signal, not putting the output in a high impedance state, when the selection signal indicates selection of the optical transceiver.