Abstract: A control circuit of a light-emitting element comprises a rectifying unit which full-wave rectifies an alternating current power supply, a clock generator which generates and outputs a clock signal (CLK), a first comparator which compares a comparison voltage (CS) corresponding to a current flowing to the light-emitting element and a reference voltage (REF), and a switching element which is set to an ON state in synchronization with the clock signal (CLK) and which is set to an OFF state when the comparison voltage (CS) becomes greater than the reference voltage (REF) at the first comparator, to switch the current flowing to the light-emitting element. In this structure, a period of the clock signal (CLK) generated in the clock generator is varied, to reduce or inhibit noise.

Abstract: In accordance with an embodiment, a control circuit for controlling a light emitting diode includes a first switching circuit having first and second inputs and an output and a second switching circuit having at least first and second inputs and an output, the first input coupled to the second input of the first switching circuit. Another embodiment includes a method for reducing flicker by generating an adjusted rectified voltage in response to a TRIAC dimmer signal from a TRIAC dimmer and a switching current in response to the adjusted rectified voltage being greater than a first reference voltage. The switching current is decreased in response to the adjusted rectified voltage becoming less than the first reference voltage. The TRIAC dimmer is turned off in response to decreasing the switching current.

Abstract: In accordance with an embodiment, a light emitting element driving circuit includes a comparator having an input connected to smoothing circuit and an output connected to a voltage-dividing circuit through a transistor. A drain-to-source resistance of the transistor is connected in parallel with a portion of the voltage dividing circuit. An output signal of the voltage dividing circuit is connected to another comparator that generates a drive transistor drive signal. The drive transistor is connected to one or more light emitting elements. In accordance with another embodiment, a reference voltage is generated in response to a rectified signal and compared with a sense voltage to generate a drive signal that is used to drive the drive transistor. Light is emitted from the one or more light emitting elements in response to the drive signal and the rectified voltage being greater than the forward voltage drops of the one or more light emitting elements.

Abstract: In a control circuit for a light-emitting device, a reference voltage generation circuit detects a full-wave rectified voltage and generates a first voltage as well as generating a second voltage by converting the rectified voltage into a DC voltage. A voltage corresponding to a difference between the first voltage and the second voltage or a voltage corresponding to a ratio of the first voltage to the second voltage is generated as a reference voltage by a subtraction circuit or by a division circuit, respectively. As a result, a change in amplitude of the reference voltage can be suppressed when amplitude of the rectified voltage is varied due to a variation in an AC input voltage supplied from an AC power supply.

Abstract: In accordance with an embodiment, a control circuit for controlling a light emitting diode includes a first switching circuit having first and second inputs and an output and a second switching circuit having at least first and second inputs and an output, the first input coupled to the second input of the first switching circuit. Another embodiment includes a method for reducing flicker by generating an adjusted rectified voltage in response to a TRIAC dimmer signal from a TRIAC dimmer and a switching current in response to the adjusted rectified voltage being greater than a first reference voltage. The switching current is decreased in response to the adjusted rectified voltage becoming less than the first reference voltage. The TRIAC dimmer is turned off in response to decreasing the switching current.

Abstract: A switching-control circuit to control switching of a transistor whose input electrode is applied with an input voltage, and turn off the transistor, when an output current from the transistor is greater than a reference current, includes: a reference-voltage-generating circuit to generate such a first-reference voltage that the reference current is reduced with reduction in an output voltage; a comparing circuit to compare a voltage corresponding to the output current with the first-reference voltage; and a driving circuit to turn on/off the transistor based on a feedback voltage corresponding to the output voltage and a second reference voltage corresponding to a target level so that the output voltage reaches the target level, when the comparing circuit determines that the output current is smaller than the reference current, and turn off the transistor when the comparing circuit determines that the output current is greater than the reference current.

Abstract: A control circuit of a light-emitting element comprises a rectifying unit which full-wave rectifies an alternating current power supply, a clock generator which generates and outputs a clock signal (CLK), a first comparator which compares a comparison voltage (CS) corresponding to a current flowing to the light-emitting element and a reference voltage (REF), and a switching element which is set to an ON state in synchronization with the clock signal (CLK) and which is set to an OFF state when the comparison voltage (CS) becomes greater than the reference voltage (REF) at the first comparator, to switch the current flowing to the light-emitting element. In this structure, a period of the clock signal (CLK) generated in the clock generator is varied, to reduce or inhibit noise.

Abstract: A control circuit of a light-emitting element comprises a rectifying unit which full-wave rectifies an alternating current power supply, a clock generator which generates and outputs a clock signal (CLK), a first comparator which compares a comparison voltage (CS) corresponding to a current flowing to the light-emitting element and a reference voltage (REF), and a switching element which is set to an ON state in synchronization with the clock signal (CLK) and which is set to an OFF state when the comparison voltage (CS) becomes greater than the reference voltage (REF) at the first comparator, to switch the current flowing to the light-emitting element. In this structure, a period of the clock signal (CLK) generated in the clock generator is varied, to reduce or inhibit noise.

Abstract: A TRIAC dimmer gates an AC waveform from an AC power source in proportion to a control signal and outputs a TRIAC pulse having part of the waveform missing. The TRIAC pulse is rectified and is applied to an LED array and the drive current flowing to the LED array is detected at a current detection resistor. The drive current value and a predetermined value are compared at a comparator and in accordance with the comparison result thereof the control transistor is turned off. Then, the TRIAC pulse is converted to a DC voltage signal and in accordance with the obtained DC voltage signal the drive current value or the predetermined value input by the comparator are changed. Furthermore, instead of the TRIAC pulse, a PWM pulse supplied from an external source may also be utilized.

Abstract: In a control circuit for a light-emitting device, a reference voltage generation circuit detects a full-wave rectified voltage and generates a first voltage as well as generating a second voltage by converting the rectified voltage into a DC voltage. A voltage corresponding to a difference between the first voltage and the second voltage or a voltage corresponding to a ratio of the first voltage to the second voltage is generated as a reference voltage by a subtraction circuit or by a division circuit, respectively. As a result, a change in amplitude of the reference voltage can be suppressed when amplitude of the rectified voltage is varied due to a variation in an AC input voltage supplied from an AC power supply.

Abstract: A light emitting element driving circuit comprising: a rectifying circuit; a voltage-dividing circuit; a transistor increasing or reducing a driving current of a light emitting element according to turning on or off a rectified voltage; a control circuit bringing the transistor to an on or off state at predetermined intervals and bringing the transistor to the other state when a voltage according to a current flowing through the transistor increases and becomes the reference voltage being divided voltage obtained by dividing the rectified voltage; and a voltage-dividing ratio adjustment circuit to set a voltage-dividing ratio of the voltage dividing circuit as a first voltage-dividing ratio to reduce the reference voltage when an amplitude of the rectified voltage is larger than predetermined amplitude and to set the voltage-dividing ratio as a second voltage-dividing ratio to increase the reference voltage when an amplitude of the rectified voltage is smaller than predetermined amplitude.

Abstract: A TRIAC dimmer gates an AC waveform from an AC power source in proportion to a control signal and outputs a TRIAC pulse having part of the waveform missing. The TRIAC pulse is rectified and is applied to an LED array and the drive current flowing to the LED array is detected at a current detection resistor. The drive current value and a predetermined value are compared at a comparator and in accordance with the comparison result thereof the control transistor is turned off. Then, the TRIAC pulse is converted to a DC voltage signal and in accordance with the obtained DC voltage signal the drive current value or the predetermined value input by the comparator are changed. Furthermore, instead of the TRIAC pulse, a PWM pulse supplied from an external source may also be utilized.

Abstract: A control circuit of a light-emitting element comprises a rectifying unit which full-wave rectifies an alternating current power supply, a clock generator which generates and outputs a clock signal (CLK), a first comparator which compares a comparison voltage (CS) corresponding to a current flowing to the light-emitting element and a reference voltage (REF), and a switching element which is set to an ON state in synchronization with the clock signal (CLK) and which is set to an OFF state when the comparison voltage (CS) becomes greater than the reference voltage (REF) at the first comparator, to switch the current flowing to the light-emitting element. In this structure, a period of the clock signal (CLK) generated in the clock generator is varied, to reduce or inhibit noise.

Abstract: A switching-control circuit to control switching of a transistor whose input electrode is applied with an input voltage, and turn off the transistor, when an output current from the transistor is greater than a reference current, includes: a reference-voltage-generating circuit to generate such a first-reference voltage that the reference current is reduced with reduction in an output voltage; a comparing circuit to compare a voltage corresponding to the output current with the first-reference voltage; and a driving circuit to turn on/off the transistor based on a feedback voltage corresponding to the output voltage and a second reference voltage corresponding to a target level so that the output voltage reaches the target level, when the comparing circuit determines that the output current is smaller than the reference current, and turn off the transistor when the comparing circuit determines that the output current is greater than the reference current.

Abstract: A switching-power-supply control circuit comprising: a first control circuit to operate a first transistor applied with an input voltage at an input electrode thereof and a second transistor connected in series to the first transistor, based on a first feedback voltage and first reference voltage, the first feedback voltage corresponding to an output voltage obtained through a connection point between the first and second transistors; and a second control circuit to allow the first control circuit to turn on/off the first and second transistors in a complementary manner so that the first feedback voltage becomes equal to the first reference voltage, when a second feedback voltage rising with rise of the output voltage is lower than a second reference voltage, and allow the first control circuit to turn off the second transistor, when the second feedback voltage is higher than the second reference voltage, according to the output voltage.

Abstract: A driver circuit to obtain a current to drive a light emitting device is reduced in a patterning area and improved in efficiency. A positive power supply voltage Vdd is applied to an anode of a white LED, while a voltage ?0.5 Vdd from a ?0.5 Vdd generation circuit is applied to a cathode of the white LED through an N-channel type MOS transistor. The ?0.5 Vdd generation circuit generates the voltage ?0.5 Vdd according to a clock ? from a clock generation circuit. A voltage of 1.5 Vdd is applied between the anode and the cathode of the white LED, as equivalent to a prior art. Since N-channel type MOS transistors are heavily used in the ?0.5 Vdd generation circuit, the driver circuit requires less patterning area to obtain the same amount of current to drive the LED as in the prior art. In addition, a parasitic capacitance is reduced to improve efficiency of the driver circuit.

Abstract: A leakage path through a parasitic diode in a charge transfer MOS transistor is cut off to prevent increase in the power consumption and loss of control of a charge pump circuit. A first charge transfer MOS transistor and a second charge transfer MOS transistor are N-channel type and are connected in series with each other. A ground electric potential VSS is supplied to a source of the first charge transfer MOS transistor as an input electric potential, and an output electric potential is obtained from an output terminal connected with a drain of the second charge transfer MOS transistor. A back gate of the first charge transfer MOS transistor is set by a first switching circuit to either an electric potential at a connecting node between the first and the second charge transfer MOS transistors or the ground electric potential VSS.

Abstract: In a over boosting prevention circuit that prevents over boosting of a voltage boosting circuit, ripples caused in the voltage boosting circuit are removed to prevent malfunctioning. The over boosting prevention circuit controls the output voltage Vout (<0V) of a charge pump circuit so that a difference (Vdd?Vout) between the power supply voltage Vdd and the output voltage Vout of the charge pump circuit does not exceed a predetermined value VMAX. That is, the charge pump circuit performs boosting operation when Vdd?Vout<VMAX, and stops the boosting operation when Vdd?Vout>VMAX. Influence of the ripples caused in the charge pump circuit is removed because the reference voltage Vref to an operational amplifier is determined relative to a ground voltage Vss.

Abstract: In a client (16), current position information and predicted future position information for an object that have been generated in another client (16) are received, and estimated current position information for the same object in virtual space are sequentially generated based on these items of information. A game server (12) controls transfer of position information received from non-specified clients to specified clients. Further, at the client (16), in a message input mode, current position information for an object is generated automatically or semi-automatically, and that current position information is transmitted to the game server (12).

Abstract: A leakage path through a parasitic diode in a charge transfer MOS transistor is cut off to prevent increase in the power consumption and loss of control of a charge pump circuit. A first charge transfer MOS transistor and a second charge transfer MOS transistor are N-channel type and are connected in series with each other. A ground electric potential VSS is supplied to a source of the first charge transfer MOS transistor as an input electric potential, and an output electric potential is obtained from an output terminal connected with a drain of the second charge transfer MOS transistor. A back gate of the first charge transfer MOS transistor is set by a first switching circuit to either an electric potential at a connecting node between the first and the second charge transfer MOS transistors or the ground electric potential VSS.