Abstract: A PLL circuit includes a phase comparator, a charge pump 20, a loop filter 30, a voltage controlled oscillator 40, a frequency divider, and a phase compensator 70. The loop filter 30 includes a resistor 31, a first capacitance element 32, and a second capacitance element 33. The phase compensator 70 is provided in parallel to the charge pump 20 and adds a differentiation term to an open-loop transfer function. The phase compensator 70 includes a buffer 71 receiving a phase difference signal output from the phase comparator and a third capacitance element 72 provided between an output terminal of the buffer 71 and an input terminal of the loop filter 30.

Abstract: A transmitter includes: an output driver that outputs differential signals to differential signal lines; first termination resistors and a first switch which are provided in series between a first reference voltage input terminal to which a reference voltage is inputted and the differential signal lines; a pulse generator that outputs a common-mode pulse to the differential signal lines during a period during which a pulse output instruction signal is at a significant level; and a detector that outputs a detection result signal indicating a magnitude relationship between a voltage level of the common-mode pulse and a threshold, during a period during which the pulse output instruction signal is at a significant level, and outputs a detection result signal indicating that the voltage level of the common-mode pulse does not exceed the threshold, during a period during which the pulse output instruction signal is at a non-significant level.

Abstract: A PLL circuit includes a phase comparator, a charge pump 20, a loop filter 30, a voltage controlled oscillator 40, a frequency divider, and a phase compensator 70. The loop filter 30 includes a resistor 31, a first capacitance element 32, and a second capacitance element 33. The phase compensator 70 is provided in parallel to the charge pump 20 and adds a differentiation term to an open-loop transfer function. The phase compensator 70 includes a buffer 71 receiving a phase difference signal output from the phase comparator and a third capacitance element 72 provided between an output terminal of the buffer 71 and an input terminal of the loop filter 30.

Abstract: A transmitter includes: an output driver that outputs differential signals to differential signal lines; first termination resistors and a first switch which are provided in series between a first reference voltage input terminal to which a reference voltage is inputted and the differential signal lines; a pulse generator that outputs a common-mode pulse to the differential signal lines; a second switch provided between the differential signal lines and the pulse generator; a detector that detects, after generation of the common-mode pulse starts, timing at which a voltage level of the common-mode pulse exceeds a threshold; and a controller that places the second switch in an on state to connect the pulse generator to the differential signal lines, and powers down the output driver and then places the first switch in an off state to allow the pulse generator to output the common-mode pulse to the differential signal lines.

Abstract: A transmitter includes: an output driver that outputs differential signals to differential signal lines; first termination resistors and a first switch which are provided in series between a first reference voltage input terminal to which a reference voltage is inputted and the differential signal lines; a pulse generator that outputs a common-mode pulse to the differential signal lines during a period during which a pulse output instruction signal is at a significant level; and a detector that outputs a detection result signal indicating a magnitude relationship between a voltage level of the common-mode pulse and a threshold, during a period during which the pulse output instruction signal is at a significant level, and outputs a detection result signal indicating that the voltage level of the common-mode pulse does not exceed the threshold, during a period during which the pulse output instruction signal is at a non-significant level.

Abstract: A transmitter includes: an output driver that outputs differential signals to differential signal lines; first termination resistors and a first switch which are provided in series between a first reference voltage input terminal to which a reference voltage is inputted and the differential signal lines; a pulse generator that outputs a common-mode pulse to the differential signal lines; a second switch provided between the differential signal lines and the pulse generator; a detector that detects, after generation of the common-mode pulse starts, timing at which a voltage level of the common-mode pulse exceeds a threshold; and a controller that places the second switch in an on state to connect the pulse generator to the differential signal lines, and powers down the output driver and then places the first switch in an off state to allow the pulse generator to output the common-mode pulse to the differential signal lines.

Abstract: A laser driver to provide a shunt current to a laser diode is disclosed. The laser driver includes a first generator to generate a first signal in response to an input signal and a second signal generator to generate a second signal in response to the input signal. The first signal has first amplitude and a first rising transition that switches the laser diode from an ON state to an OFF state of the laser diode. The second signal has second amplitude smaller than the first amplitude and a second rising transition having a delay from the first rising transition. The laser driver further includes an output terminal to output the shunt current including the first signal and the second signal.

Abstract: A laser driver drives a laser diode by increasing and decreasing a drive current by a differential signal having a pair of positive phase and negative phase components and comprises an upper voltage-controlled current, source increasing the drive current responding to an increase of the positive phase component of the differential signal, a lower voltage-controlled current source for decreasing the drive current responding to an increase of the negative Phase signal of the differential signal, and an output terminal, connected to output terminals of the voltage-controlled current sources, for outputting the drive current. The voltage-controlled current source has a band-pass filter with a gain for the positive phase component set greater in a predetermined frequency region than in a frequency region other than the predetermined frequency region.

Abstract: A moisture absorbent for an organic EL element having hydrophobicity and no reduction in moisture absorption speed, and a method for producing the moisture absorbent are provided. The moisture absorbent for an organic EL element includes, as a main component, calcium oxide particles each having an alkoxide layer on the surface thereof. Furthermore, the method for producing a moisture absorbent for an organic EL element includes dry-pulverizing calcium oxide in the presence of an alcohol, and thereafter dry-treating the pulverized calcium oxide.

Abstract: A driver for an EA-DFB device includes a switching device. The EA-DFB device is put between a positive power supply and a negative power supply as connected in series to a bias current source and the switching device. The EA device is modulated by the switching device in the differential mode. The switching device includes paired transistors each having a load, one of which is a resistor connected in parallel to the EA device, while, the other is constituted by a resistive element.

Abstract: A laser diode (LD) driver to suppress the excess emission of an LD is disclosed. The LD driver has the shunt configuration with a driving transistor connected in parallel to the LD to shunt the bias current provided to the LD. The driver further provides a protection circuit to divide the bias current when the bias current is active but the driving transistor is turned off at an instant of the power on and off of the LD driver.

Abstract: A differential circuit with a function to compensate the gain enhancement due to the self-heating of the transistor is disclosed. The differential circuit includes an equalizer unit coupled with one of paired transistors. The other of the paired transistor receives the input signal to be amplified. The base level, or the base-emitter bias, is oppositely modulated by the input signal through the common emitter, which causes the modification of the base current. The equalizer unit reduces the variation of the base level only in low frequencies where the self-heating effect of the transistor appears.

Abstract: A moisture absorbent for an organic EL element having hydrophobicity and no reduction in moisture absorption speed, and a method for producing the moisture absorbent are provided. The moisture absorbent for an organic EL element includes, as a main component, calcium oxide particles each having an alkoxide layer on the surface thereof. Furthermore, the method for producing a moisture absorbent for an organic EL element includes dry-pulverizing calcium oxide in the presence of an alcohol, and thereafter dry-treating the pulverized calcium oxide.

Abstract: A shunt driver for driving an LD is disclosed. The shunt driver has the push-pull arrangement with the high side driver and the low side driver. The high side driver is driven by a positive phase signal superposed with a negative phase signal with a delay and a less amplitude with respect to the positive phase signal. The low side driver is driven by a negative phase signal superposed with a positive signal with a delay and a less amplitude compared to the positive phases signal. Adjusting the magnitude of the superposed signals, the driving current for the LD has the peaking in the rising and falling edges thereof.

Abstract: A laser diode (LD) driver to suppress the excess emission of an LD is disclosed. The LD driver has the shunt configuration with a driving transistor connected in parallel to the LD to shunt the bias current provided to the LD. The driver further provides a protection circuit to divide the bias current when the bias current is active but the driving transistor is turned off at an instant of the power on and off of the LD driver.

Abstract: A shunt driver for driving an LD is disclosed. The shunt driver has the push-pull architecture with the high side driver and the low side driver. The high side driver is driven by a positive phase signal superposed with a signal with a phase opposite to the negative phase signal. The low side driver is driven by a negative phase signal superposed with a signal with a phase opposite to the positive phase signal. Adjusting the magnitude of the superposed signals, the driving current for the LD has the peaking in the rising and falling edges thereof.

Abstract: An LD-Driver with the push-pull arrangement is disclosed. The driver includes the high side driver driven by the positive phase signal and the low side driver driven by the negative phase signal. When the positive phase signal is in HIGH, the high side driver becomes ON and the LD driver provides additional current to the bias current for the LD; while, when the negative phase signal is in HIGH, the low side driver becomes ON and the LD driver extracts a portion of the bias current for the LD.

Abstract: A differential circuit with a function to compensate the gain enhancement due to the self-heating of the transistor is disclosed. The differential circuit includes an equalizer unit coupled with one of paired transistors. The other of the paired transistor receives the input signal to be amplified. The base level, or the base-emitter bias, is oppositely modulated by the input signal through the common emitter, which causes the modification of the base current. The equalizer unit reduces the variation of the base level only in low frequencies where the self-heating effect of the transistor appears.

Abstract: A trans-impedance amplifier (TIA) for a light-receiving circuit is disclosed where the TIA reduces the power consumption as suppressing the degradation of the signal quality in high frequency regions. The TIA comprises a primary core, a dummy core, and a differential amplifier that receives each output of two cores in the differential mode. Two cores have an arrangement substantially same to each other except that the power consumption thereof is smaller in the dummy core. Because the output impedance of two cores becomes substantially equal, the scattering parameter of the common mode to the differential mode at the output of the primary core becomes small enough.

Abstract: A driver for EA-DFB device is disclosed. The EA-DFB device is put between the positive power supply and the negative power supply as connected in series to the bias current source and the switching device. The EA device is modulated by the switching device in the differential mode. The switching device includes paired transistors each having a load, one of which is a resistor connected in parallel to the EA device, while, the other is constituted by a resistive element.