| Patent application number | Description | Published |
|---|
| 20080258784 | Controller IC, DC-AC conversion apparatus, and parallel running system of DC-AC conversion apparatuses - 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. | 10-23-2008 |
| 20080285321 | DC-AC Converter and Method of Supplying AC Power - 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. | 11-20-2008 |
| 20080303447 | INVERTER APPARATUS - An inverter converts input voltage to AC driving voltage to supply it to a load. Secondary coil of an output transformer are connected to the load. Secondary coil of a main transformer are connected to the primary coil of the output transformer. A driving circuit applies switching voltage alternately repeating the input voltage and ground voltage to the primary coil of the main transformer. | 12-11-2008 |
| 20090015177 | POWER SUPPLY DEVICE AND LIGHT-EMITTING DEVICE AND ELECTRONIC EQUIPMENT USING SUCH POWER SUPPLY DEVICE - In a power supply apparatus for supplying a power to a plurality of CCFLs, a plurality of transformers are provided for the respective CCFLs. Respective primary coils of the transformers are connected to each other in series so as to constitute one current path. One ends of respective secondary coils of the transformers are connected to the plurality of loads. An AC power supply unit generates an AC voltage and applies the AC voltage to the other ends of the secondary coils of the plurality of transformers. A capacitor is disposed on the current path formed with the primary coils of the transformers. A first fixed voltage is applied to one end of the current path, and a second fixed potential different from the first fixed voltage is applied to the other end of the current path. | 01-15-2009 |
| 20090021970 | DC-AC CONVERTER, CONTROLLER IC THEREFOR, AND ELECTRONIC APPARATUS UTILIZING THE DC-AC CONVERTER - An inverter controls the power supplied to a load such as a CCFL connected to a secondary winding of a transformer by means of pulse width modulation (PWM) control of the switches of a semiconductor switching circuit connected to the primary winding of the transformer. The current and voltage supplied to the load are fed back to the inverter in the form of a current error signal and a voltage error signal, respectively, from which a feedback signal is formed in accordance with the magnitudes of these signals. Thus, when the DC supply voltage of a DC power supply sharply rises, the inverter changes the feedback signal directly, that is, without waiting for the changes to occur in the load current and load voltage, so as to reduce the power supplied to the load. Thus, over-current and resultant viewer's discomfort is suppressed. Sudden shut down of the inverter are also prevented from occurring. | 01-22-2009 |
| 20090066265 | INVERTER - A soft start circuit generates a soft start voltage Vss which changes with time at a starting time of lighting an EEFL. A pulse width modulator generates a PWM signal Vpwm whose duty ratio is feedback-controlled so that a feedback voltage Vfb corresponding to an output voltage Vdrv of an inverter conforms to the soft start voltage Vss. A logical control unit performs switching control of a voltage of a primary coil of a transformer on the basis of the PWM signal Vpwm from the pulse width modulator. The soft start circuit executes at least one striking operation in which the soft start voltage Vss is raised with time, lowered when being reached to a first voltage level VH, and raised again when being lowered to a second voltage level VL lower than the first voltage level VH. | 03-12-2009 |
| 20090072754 | DC-AC CONVERTER, CONTROLLER IC THEREFOR, AND ELECTRONIC APPARATUS UTILIZING SUCH DC-AC CONVERTER - 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. | 03-19-2009 |
| 20090160357 | INVERTER, ITS DRIVE METHOD, LIGHT EMITTING DEVICE AND LIQUID CRYSTAL TELEVISION USING THE SAME - The switching timing is flexibly set in an inverter. | 06-25-2009 |
| 20090185401 | DC-AC Converter and Controller IC Thereof - 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. | 07-23-2009 |
| 20090237969 | Controller IC, DC-AC conversion apparatus, and parallel running system of DC-AC conversion apparatuses - 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. | 09-24-2009 |
| 20090273738 | INVERTER, ITS CONTROL CIRCUIT, AND LIGHT EMITTING DEVICE AND LIQUID CRYSTAL TELEVISION USING THE SAME - A pulse width modulator generates a PWM signa whose duty ratio is feedback-controlled so that a detection voltage according to a current across a secondary coil of a transformer is brought close to a reference voltage. A logic control unit performs a switching control of the current across the primary coil of the transformer, based on the PWM signal outputted from the pulse width modulator. A first protection circuit detects a circuit failure of an inverter and stops the switching control of the inverter when the circuit failure continues for a predetermined duration of error detection time. A second protection circuit monitors a feedback voltage corresponding to an output voltage of the inverter, and lowers the reference voltage sets the duration of error detection time short when the feedback voltage is lower than a predetermined threshold voltage. | 11-05-2009 |
| 20100014336 | DC-AC Converter and Method of Supplying AC Power - 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 switch 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. | 01-21-2010 |
| 20100020269 | FLUORESCENT LAMP DRIVING APPARATUS, LIGHT EMITTING APPARATUS AND LIQUID CRYSTAL TELEVISION - In an apparatus for driving a CCFL, a first inverter outputs a first alternating current (AC) voltage to one end of the CCFL. A second inverter outputs a second AC voltage having a reversed phase to the first AC voltage to the other end of the CCFL. A first current-voltage converting circuit converts a secondary current of a first transformer in the first inverter to a voltage and outputs the voltage as a first detection voltage. A second current-voltage converting circuit converts a secondary current of a second transformer in the second inverter to a voltage and outputs the voltage as a second detection voltage. A first abnormality detection circuit determines a circuit abnormality when the potential difference between the first and second detection voltages exceeds a predetermined first threshold voltage. | 01-28-2010 |
| 20100039571 | TRIANGULAR-WAVE GENERATING CIRCUIT SYNCHRONIZED WITH AN EXTERNAL CIRCUIT - A charge-discharge circuit charges or discharges a capacitor having a fixed electric potential at one end. A first comparator compares an output voltage of the capacitor with a first threshold voltage and outputs a first comparison signal in accordance with a comparison result. An edge detecting circuit detects an edge of a synchronization signal input from the outside and having a frequency of about ½ of a triangular-wave signal generated by the triangular-wave generating circuit, and outputs an edge detection signal that will be at a predetermined level for each of the detected edges. A charge-discharge controller receives the first comparison signal that is output from the first comparator and the edge detection signal that is output from the edge detecting circuit, and switches between a charge state and a discharge state of the charge-discharge circuit in accordance with a level transition of these signals. A voltage of the capacitor is output as a triangular-wave signal | 02-18-2010 |
| 20100188614 | DRIVING APPARATUS AND METHOD FOR FLUORESCENT LAMP - A driving apparatus includes an inverter to supply an AC voltage to Cold Cathode Fluorescent Lamps (CCFLs) to be driven. A first detection signal generation unit generates a first detection signal occurring by driving a first CCFL with the AC voltage. A second detection signal generation unit generates a second detection signal occurring by driving a second CCFL with the AC voltage. An abnormality detection circuit generates an abnormality detection signal corresponding to a difference between amplitudes of the first detection signal and the second detection signal. The driving apparatus compares the abnormality detection signal with a predetermined threshold value to execute a circuit protecting operation in accordance with a comparison result. | 07-29-2010 |
| 20100277090 | TRIANGULAR-WAVE GENERATING CIRCUIT, AND INVERTER, LIGHT EMITTING DEVICE AND LIQUID CRYSTAL TELEVISION USING THE CIRCUIT - A first comparator compares an output voltage Vout appearing at a capacitor with a maximum threshold voltage Vmax. A second comparator compares the output voltage Vout with a minimum threshold voltage Vmin. An edge detection circuit detects an edge of a synchronization signal SYNC having approximately ½ of frequency of the output voltage Vout and outputs an edge detection signal SE. A charge-discharge control unit refers to the first and the second comparison signal, and sets the charge-discharge circuit to a discharging state when the output voltage Vout becomes higher than the maximum threshold voltage Vmax and sets the charge-discharge circuit to a charging state when the output voltage Vout becomes lower than the minimum threshold voltage Vmin. When the edge signal SE becomes the predetermined level, the charge-discharge control unit switches the charging state and the discharging state of the charge-discharge circuit. | 11-04-2010 |
