摘要:
An optical communication device which can be operated at high speed is provided. For example, the optical communication device includes: a pre-amplifier circuit PREAMP1 amplifying a current signal Iin from a photodiode PD, and converting an amplified signal into a voltage signal; and an operating-point controller circuit VTCTL1 controlling an operation of the PREAMP1. The PREAMP1 includes a negative feedback path formed by a feedback resistance Rf1, and includes: a level-shift circuit LS1 level-shifting in accordance with an operating-point control signal Vcon; and an amplifier circuit AMP1 connected to a subsequent stage of the LS1 and performing an amplifying operation with a high gain. The VTCTL1 includes a replica circuit configured by the same circuit and circuit parameter as those of the AMP1 and electrically connected between the input and the output, and generates the Vcon so that an output DC level of this replica circuit is matched with an input DC level of the AMP1.
摘要:
An optical communication device which can be operated at high speed is provided. For example, the optical communication device includes: a pre-amplifier circuit PREAMP1 amplifying a current signal Iin from a photodiode PD, and converting an amplified signal into a voltage signal; and an operating-point controller circuit VTCTL1 controlling an operation of the PREAMP1. The PREAMP1 includes a negative feedback path formed by a feedback resistance Rf1, and includes: a level-shift circuit LS1 level-shifting in accordance with an operating-point control signal Vcon; and an amplifier circuit AMP1 connected to a subsequent stage of the LS1 and performing an amplifying operation with a high gain. The VTCTL1 includes a replica circuit configured by the same circuit and circuit parameter as those of the AMP1 and electrically connected between the input and the output, and generates the Vcon so that an output DC level of this replica circuit is matched with an input DC level of the AMP1.
摘要:
An amplifier circuit block and a compensation circuit block are provided. The amplifier circuit block includes an analog adder for subtracting an output signal of the compensation circuit block from an input signal and an amplifier circuit operating in a wide band. The compensation circuit block includes an amplifier circuit with a low offset voltage and a low noise in a low frequency region, an analog adder block for subtracting an output signal of the amplifier circuit from an output signal of the amplifier circuit and generating a differential signal thereof, and a feedback circuit block for negatively feeding back the differential signal to the analog adder. The amplifier circuit block can reduce the offset voltage and the low-band noise by the negative feedback of the differential signal, and at the same time, the operation band of the entire amplifier circuit can be decided by the characteristic of the amplifier circuit.
摘要:
An amplifier circuit block and a compensation circuit block are provided. The amplifier circuit block includes an analog adder for subtracting an output signal of the compensation circuit block from an input signal and an amplifier circuit operating in a wide band. The compensation circuit block includes an amplifier circuit with a low offset voltage and a low noise in a low frequency region, an analog adder block for subtracting an output signal of the amplifier circuit from an output signal of the amplifier circuit and generating a differential signal thereof, and a feedback circuit block for negatively feeding back the differential signal to the analog adder. The amplifier circuit block can reduce the offset voltage and the low-band noise by the negative feedback of the differential signal, and at the same time, the operation band of the entire amplifier circuit can be decided by the characteristic of the amplifier circuit.
摘要:
A transmitting and receiving technique in which a load on data signal lines is reduced while maintaining a communication quality, thereby making it possible to improve the throughput of data channels. In a transceiver, a transmitter side has an encoder circuit that transmits a bit sequence obtained by encoding link information to a clock signal line, and a receiver side has a clock and data recovery circuit 17 that extracts a clock component from a signal received from the clock signal line, a decoder circuit 19 that decodes the extracted signal to reproduce the link information, and a bit deskew circuit 21 that adjusts a skew that is lower than one bit on the basis of a clock component.
摘要:
A transmitting and receiving technique in which a load on data signal lines is reduced while maintaining a communication quality, thereby making it possible to improve the throughput of data channels. In a transceiver, a transmitter side has an encoder circuit that transmits a bit sequence obtained by encoding link information to a clock signal line, and a receiver side has a clock and data recovery circuit 17 that extracts a clock component from a signal received from the clock signal line, a decoder circuit 19 that decodes the extracted signal to reproduce the link information, and a bit deskew circuit 21 that adjusts a skew that is lower than one bit on the basis of a clock component.
摘要:
A signal transmit-receive device of the invention reduces the number of high-speed signal lines required for connecting a transmitting circuit group and a receiving circuit group, and for running a loopback test on a signal transmit-receive device. The loopback test circuit uses an error detecting circuit, a test signal producing circuit, and a wiring for transmitting error information. The error detecting circuit compares a test signal pattern defined in advance by a first communication device and a received signal pattern. The test signal producing circuit produces the test signal pattern based on error information. If an error is detected, the error signal is transmitted to the test signal producing circuit through the wiring. The test signal producing circuit produces a predetermined test signal pattern if the error signal DE has an L level; upon receiving H level, it sends back the predetermined test signal pattern to the first communication device.
摘要:
A logic circuit determines the power consumption of a semiconductor integrated device by taking into consideration the variation of the rate of operation. A control signal (TEST) is applied to each control signal input port (Tin) of flip-flop circuits of flip-flop circuit groups and a logic gate circuit having a plurality of input ports A and B in a combined circuit group. If the control signal (TEST) is low, both the flip-flop circuits and the logic gate circuit operate normally. However, if the control signal (TEST) is high, each of them performs the power consumption test. Regardless of the value of input signals applied to input ports D1 and D2 of the flip-flop circuits, the flip-flop circuits are controlled to have a repetitive output signal of high and low levels at ports Q1 and Q2, in synchronism with a clock signal. Through this operation test, operational failure is reduced and the quality of semiconductor chip production is guaranteed, because it is possible to predict accurately the power consumption when designing the logic circuit due to the relationship between the rate of operation and the power consumption.
摘要:
The delay time for the transfer of data signals between pluralities of logic circuits is automatically regulated to be in a desired range. In order to regulate the delay time of the data signal transfer, a common standard signal SYNC is distributed to the logic circuits from a standard signal generator source. In the sending side of one logic circuit, the standard signal is applied through a selector circuit to a flip-flop circuit and then transferred to the receiving side of another logic circuit. Specifically, the transferred standard signal passes through a variable delay circuit to a flip flop circuit on the receiving side of the other logic circuit where it is compared with the standard signal received from the standard signal generator source, which has passed through a delay circuit of a standard delay value. The result of the comparison is used to adjust the variable delay circuit that controls the delay time for the transferred standard signal. Once the variable delay circuit is adjusted with the standard signal, the selector selects normal data signals for transfer between the logic circuits with the appropriate delay. The standard signal can also be used to synchronize the generation of test pattern signals generated in each of the logic circuits.
摘要:
A condenser having a huge area is required to reduce a noise on LSI power supply nets (−&Dgr;VDD) of an integrated circuit because a bypass condenser can only utilize a part of accumulated electric charges. A noise of LSI power supply nets is suppressed by generating a noise of a reversed polarity (+&Dgr;VDD) to the noise on the LSI power supply nets (−&Dgr;VDD), based upon a noise reducing circuit discharging a condenser charged with a high voltage. A noise reduction effect equivalent to a bypass condenser having a large capacity is obtained even when a condenser having a small capacity is used.