Abstract: A DC power source voltage is supplied to a center tap of a primary winding, and first and second semiconductor switches alternately turned on are disposed between each of both ends of the primary winding and a common potential point, and a current flowing through a load is fed back and PWM control of each of the semiconductor switches is performed. Also, snubber circuits are respectively connected between a ground and the center tap of the primary winding, and an abnormal high voltage at the time of switching is reduced. Also, a parallel running of plural inverters is simply performed by disposing PWM comparators corresponding to the first and second semiconductor switches.

Abstract: A multiplicity of synchronized inverters for driving a multiplicity of loads such as CCFLs that require high ac voltages are arranged in close proximity of the respective loads and controlled in phase. A frequency determination capacitor and a frequency determination resistor are connected to one of the inverters to generate a triangular wave signal and a clock signal. The triangular wave signal and clock signal thus generated are supplied to other inverters to synchronize all the loads so that they can be controlled in phase. The resistance of the frequency determination resistor is set to a substantially small magnitude at the time of startup to increase the frequency of the triangular wave signal, thereby enabling quick startup of the loads.

Abstract: First and second semiconductor switches which are activated alternately are provided between ends of a primary winding and a common potential point, wherein a DC power supply voltage is supplied to a center tap. An electric current flowing into a load is fed back to thereby subject the semiconductor switches to PWM control. Series circuits consisting of capacitors and semiconductor switches are connected between the center tap of the primary winding and the ends of the same. The semiconductor switches are activated in synchronism with the first and second semiconductor switches, thereby preventing occurrence of an anomalous high voltage, which would otherwise be caused at the time of switching operation.

Abstract: A semiconductor switch circuit is connected to a primary winding of a transformer having a secondary winding connected to a load. The semiconductor switch circuit has switches controlled by PWM to provide a controlled constant current. In the inventive inverter, constant current control is performed by PWM operation of the switches of the semiconductor switch circuit. The inverter cuts off electricity to the control circuit when putting the control circuit into a standby state if a run-stop signal gains a logical stop-state. At the same time as the run-stop signal gaining the stop-state, switch drive signals enabling the switches of the semiconductor switch circuit are turned off. Thus, over-current can be prevented from flowing in the load when the control circuit is put into the standby state.

Abstract: Primary and secondary regions are electrically insulated from each other. The first and second pulse transformers are provided to the respective transistors in the switching circuit. Secondary windings of the first and second pulse transformers are connected to control terminals of the transistors. The control circuit supplies switching voltages to primary windings of the pulse transformers based on a feedback signal fed back through a feedback line. A primary winding of a transformer, the switching circuit, and the secondary windings are disposed on the primary region. A secondary winding of the transformer, the primary windings, the feedback line, and the control circuit are disposed on the secondary region.

Abstract: A switching circuit includes a plurality of transistors connected to a primary winding of the transformer and alternately applies an input voltage and a ground voltage to the primary winding according to turning-on and turning-off of each of the transistors. A plurality of capacitors are provided to the respective fluorescent lamps. One ends of the capacitors are commonly connected to a secondary winding of the transformer, and the other ends thereof are connected to the respective fluorescent lamps. A control circuit monitors a current flowing through a predetermined current path among current paths of the entire circuits including an inverter and the fluorescent lamps and performs feedback control of the turning-on and turning-off states of a plurality of the transistors of the switching circuit to adjust supply of switching power to the primary winding of the transformer so that the monitored current can be maintained in a predetermined condition.

Abstract: A dc-ac converter capable of supplying a finely regulated ac drive voltage to a load is provided. For this purpose, the converter includes, in a primary winding of a transformer, a full-bridge or half-bridge type semiconductor switch circuit whose switches can be controlled by pulse-width modulation. Transformer has a secondary winding for connection with a load. Based on PWM signals and by use of adequate switching logics for controlling multiple semiconductor switches, sophisticated control including zero-current switching and penetrating current prevention can be effected. Moreover, by means of regulated burst control of the ratio of on-duty period to off-duty period together with pulse-width modulation control, power supplied to the load can be regulated over a wide range beyond the limits of control obtained by the pulse-width modulation.

Abstract: An inventive inverter has a semiconductor switch circuit connected to the primary winding of a transformer. The semiconductor switch circuit is respectively controlled by PWM to supply a constant current to the load connected to a secondary winding of the transformer. The inverter is capable of deliberately regulating its ac power output to the load and lowering the lower limit of the output power through control of the intermittent operation, in which an error signal for carrying out the PWM control is reduced to zero during each off-duty period. In addition, the error signal for the PWM control is slowly decreased or increased in each shift from an off-duty period to on-duty period, and vise versa, by charging or discharging the capacitor in a feedback circuit, thereby allowing slow start or slow end of the respective on-off operations for the constant current control through the PWM.

Abstract: The present invention relates to a release sheet which comprises a mat making layer forming a refined uneven of mat style on a surface, the mat making layer being provided on at least one surface of a substrate sheet, and a release layer formed with a coating film layer of releasable resin containing ultra micro particles having an average particle size of 0.01 to 0.3 ?m, the release sheet being provided on a surface of the mat making layer. The release sheet of the present invention has superior heat resistance and mechanical strength for a long time, and can prevent change of mat style having low gloss of the surface or of gloss, even if repeat uses are conducted. By using the release sheet of the present invention, a formed article such as synthetic leathers and decorative laminated plates having uniformity quality, can be provided.

Abstract: A multiplicity of electronic devices is provided to generate triangular wave signals variable between an upper and lower limit voltages by charging or discharging capacitors. One of the triangular wave signals serves as a master triangular wave signal for controlling the phases of the remaining (or slave) triangular wave signals. A detection signal is generated every time the master triangular wave signal reaches predetermined threshold levels. In response to the detection signal, a capacitor associated with one slave triangular signal is promptly discharged to bring the slave triangular signal to the lower limit voltage, whereby the respective slave triangular wave signals are synchronized to be offset in phase relative to the master triangular wave signal by respective predetermined phase angles.

Abstract: A control circuit for an inverter for driving a fluorescent lamp includes a first triangular wave signal generator for use in analog dimming control, and a second triangular wave signal generator for use in burst dimming. The first triangular wave signal generator oscillates at a frequency higher than that of the second triangular wave signal generator. A semiconductor substrate on which the control circuit is integrated is partitioned into at least two areas by a fixed potential wiring. A circuit block including the first triangular wave signal generator is placed in one of the areas, and a circuit block including the second triangular wave signal generator and the comparator for burst dimming is placed in the other area.

Abstract: An inverter has a semiconductor switch circuit provided in the primary circuit of a transformer. The switch circuit is controlled by a PWM circuit. The switch circuit is operated on the basis of an intermittent-operation signal having an ON state and OFF state to: set an error signal to a substantially zero level during OFF periods; gradually increase the error signal upon transition from an OFF state to an ON state; and gradually decrease the error signal upon transition from an ON state to an OFF state. Each ON phase of the intermittent operation is slowly started and slowly ended through charging and discharging of a capacitor provided in a feedback circuit. This enables concomitant application of constant-current control and intermittent-operation control to the inverter, which in turn provides a broad range of power that can be supplied to a load, significantly reduces hamming of the transformer, and prevents over-current from occurring in the inverter.

Abstract: First and second semiconductor switches which are activated alternately are provided between ends of a primary winding and a common potential point, wherein a DC power supply voltage is supplied to a center tap. An electric current flowing into a load is fed back to thereby subject the semiconductor switches to PWM control. Series circuits consisting of capacitors and semiconductor switches are connected between the center tap of the primary winding and the ends of the same. The semiconductor switches are activated in synchronism with the first and second semiconductor switches, thereby preventing occurrence of an anomalous high voltage, which would otherwise be caused at the time of switching operation.

Abstract: An inventive inverter has a semiconductor switch circuit connected to the primary winding of a transformer. The semiconductor switch circuit is respectively controlled by PWM to supply a constant current to the load. connected to a secondary winding of the transformer. The inverter is capable of deliberately regulating its ac power output to the load and lowering the lower limit of the output power through control of the intermittent operation, in which an error signal for carrying out the PWM control is reduced to zero during each off-duty period. In addition, the error signal for the PWM control is slowly decreased or increased in each shift from an off-duty period to on-duty period, and vise versa, by charging or discharging the capacitor in a feedback circuit, thereby allowing slow start or slow end of the respective on-off operations for the constant current control through the PWM.

Abstract: An inverter has a semiconductor switch circuit in the primary winding of a transformer such that each of the switches of the switch circuit is controlled by pulse-width modulation (PWM) to supply a constant ac current and a constant ac voltage to a load, such as a cold cathode fluorescent light, connected to a secondary winding of the transformer. A common slow-start control circuit is provided in the inverter circuit to enable a common slow startup of the PWM control of the output voltage and output current. This arrangement suppresses an excessive voltage and an inrushing current during a startup.

Abstract: A multiplicity of synchronized inverters for driving a multiplicity of loads such as CCFLs that require high ac voltages are arranged in close proximity of the respective loads and controlled in phase. A frequency determination capacitor and a frequency determination resistor are connected to one of the inverters to generate a triangular wave signal and a clock signal. The triangular wave signal and clock signal thus generated are supplied to other inverters to synchronize all the loads so that they can be controlled in phase. The resistance of the frequency determination resistor is set to a substantially small magnitude at the time of startup to increase the frequency of the triangular wave signal, thereby enabling quick startup of the loads.

Abstract: A multiplicity of electronic devices is provided to generate triangular wave signals variable between an upper and lower limit voltages by charging or discharging capacitors. One of the triangular wave signals serves as a master triangular wave signal for controlling the phases of the remaining (or slave) triangular wave signals. A detection signal is generated every time the master triangular wave signal reaches predetermined threshold levels. In response to the detection signal, a capacitor associated with one slave triangular signal is promptly discharged to bring the slave triangular signal to the lower limit voltage, whereby the respective slave triangular wave signals are synchronized to be offset in phase relative to the master triangular wave signal by respective predetermined phase angles.

Abstract: First and second semiconductor switches which are activated alternately are provided between ends of a primary winding and a common potential point, wherein a DC power supply voltage is supplied to a center tap. An electric current flowing into a load is fed back to thereby subject the semiconductor switches to PWM control. Series circuits consisting of capacitors and semiconductor switches are connected between the center tap of the primary winding and the ends of the same. The semiconductor switches are activated in synchronism with the first and second semiconductor switches, thereby preventing occurrence of an anomalous high voltage, which would otherwise be caused at the time of switching operation.

Abstract: A semiconductor switch circuit is connected to a primary winding of a transformer having a secondary winding connected to a load. The semiconductor switch circuit has switches controlled by PWM to provide a controlled constant current. In the inventive inverter, constant current control is performed by PWM operation of the switches of the semiconductor switch circuit. The inverter cuts off electricity to the control circuit when putting the control circuit into a standby state if a run-stop signal gains a logical stop-state. At the same time as the run-stop signal gaining the stop-state, switch drive signals enabling the switches of the semiconductor switch circuit are turned off. Thus, over-current can be prevented from flowing in the load when the control circuit is put into the standby state.

Abstract: An inventive inverter has a semiconductor switch circuit connected to the primary winding of a transformer. The semiconductor switch circuit is respectively controlled by PWM to supply a constant current to the load. connected to a secondary winding of the transformer. The inverter is capable of deliberately regulating its ac power output to the load and lowering the lower limit of the output power through control of the intermittent operation, in which an error signal for carrying out the PWM control is reduced to zero during each off-duty period. In addition, the error signal for the PWM control is slowly decreased or increased in each shift from an off-duty period to on-duty period, and vise versa, by charging or discharging the capacitor in a feedback circuit, thereby allowing slow start or slow end of the respective on-off operations for the constant current control through the PWM.

Abstract: Disclosed is a conventional safety razor having a sounding board disposed immediately behind and approximately coextensive and even with the razor head, the sounding board being in the form of a thin plastic plate extending upwardly from the razor handle, with the plate serving as both a means for scraping hair stubble on human skin, as well as a means for audibly amplifying vibrations induced thereby. This alerts the user to the continued presence of objectionable hair stubble so that the shaving process is repeated with or without a change of safety razors or razor blades as required. Alternatively, a miniature solid-state microphone may be mounted on the safety razor for sensing the vibrations and driving an audio speaker through an amplifier/filter network.