Abstract: A lighting system is provided with a dimmer apparatus and lighting equipment that are connected to each other via a two-wire power supply line. The dimmer apparatus generates a DC voltage including a dimming PWM signal having a PWM amplitude corresponding to a dimming control signal, and outputs the DC voltage to the lighting equipment. The lighting equipment includes at least one light emitting element that emits light by a DC current based on the DC voltage, and a current control circuit. The second control circuit modulates the dimming PWM signal included in the DC voltage, and controls brightness of the light emitting element, so that a DC current corresponding to a duty ratio of a modulated dimming PWM signal flows through the light emitting element based on the duty ratio of the dimming PWM signal.

Abstract: A first current generator circuit generates a first current having a current value variable in accordance with a first control signal. A second current generator circuit generates a second current by limiting the first current so as to have a current value variable in accordance with a second control signal. A third current generator circuit generates a third current by limiting the second current so as to have a current value variable in accordance with a third control signal, and supplies the third current to the semiconductor laser element. Rates at which the first and second control signals change are set to be lower than a rate at which the third control signal changes.

Abstract: A laser drive apparatus includes a DA converter including current sources of a number corresponding to a bit number of a digital input code, and switches of a number corresponding to the number of bits. The switches are connected to the current sources and selectively switch presence or absence of output of a control current therefrom, and the DA converter outputs control currents corresponding to the digital input code as output respective currents from the switches. The laser drive apparatus includes a driver circuit including current mirror circuits that generate a drive current corresponding to each output current based on each output current to drive a laser diode. In the driver circuit, the current sources are divided into current source sets, to which the current mirror circuits are connected via the switches, and generate a drive current corresponding to each output current to drive the laser diode.

Abstract: A constant voltage generator circuit is provided with an operational amplifier including a feedback circuit having a first resistor, and an output transistor. The operational amplifier generates a feedback voltage generated by dividing an output voltage between an output terminal and a substrate voltage potential of the constant voltage generator circuit by the first resistor and a second resistor. Then, the operational amplifier is configured to amplify a voltage potential difference between a predetermined reference voltage and the feedback voltage and to output a control voltage. The output transistor controls an output voltage based on the control voltage from the operational amplifier, and the feedback circuit is further configured to superimpose high-frequency noise components from the substrate voltage potential onto the feedback voltage.

Abstract: A first current generator circuit generates a first current having a current value variable in accordance with a first control signal. A second current generator circuit generates a second current by limiting the first current so as to have a current value variable in accordance with a second control signal. A third current generator circuit generates a third current by limiting the second current so as to have a current value variable in accordance with a third control signal, and supplies the third current to the semiconductor laser element. Rates at which the first and second control signals change are set to be lower than a rate at which the third control signal changes.

Abstract: A reference voltage generator circuit is provided with a first voltage generator circuit that generates a first direct-current voltage; a second voltage generator circuit that generates a second direct-current voltage; and an operational amplifier that generates a voltage difference between the first and second direct-current voltages. The reference voltage generator circuit generates a reference voltage based on a band gap by controlling currents flowing in the first and second voltage generator circuits based on the voltage difference, and includes a third voltage generator circuit including a PNP bipolar transistor, which is connected in parallel with the first voltage generator circuit. The third voltage generator circuit generates a third direct-current voltage corresponding to a base current flowing in the PNP bipolar transistor, and applies it to the operational amplifier with the first direct-current voltage.

Abstract: An overvoltage protection circuit is provided which is connected between a rectifier circuit and a load including an input capacitor element connected to both ends of the load. The overvoltage protection circuit includes a semiconductor switch connected between the rectifier circuit and the load, and a control circuit controls the semiconductor switch. When the rectified voltage exceeds a predetermined value, the control circuit turns off the semiconductor switch, and detects a voltage potential difference between both ends of the semiconductor switch, and then, for an interval when the voltage potential difference is zero or a predetermined minute value, the control circuit generates a control voltage for turning on the semiconductor switch, and outputs the control voltage to a control terminal of the semiconductor switch. The overvoltage protection circuit includes a current change circuit that gradually changes a current flowing through the semiconductor switch.

Abstract: An overvoltage protection circuit is provided which is connected between a rectifier circuit and a load including an input capacitor element connected to both ends of the load. The overvoltage protection circuit includes a semiconductor switch connected between the rectifier circuit and the load, and a control circuit controls the semiconductor switch. When the rectified voltage exceeds a predetermined value, the control circuit turns off the semiconductor switch, and detects a voltage potential difference between both ends of the semiconductor switch, and then, for an interval when the voltage potential difference is zero or a predetermined minute value, the control circuit generates a control voltage for turning on the semiconductor switch, and outputs the control voltage to a control terminal of the semiconductor switch. The overvoltage protection circuit includes a current change circuit that gradually changes a current flowing through the semiconductor switch.

Abstract: A power supply apparatus of the present invention has an input terminal and an output terminal, and converts an input voltage at the input terminal into a predetermined output voltage at the output terminal. The power supply apparatus includes first and second power supply circuits and a smoothing capacitor. The first power supply circuit is coupled between the input terminal and the output terminal, and converts the input voltage into a predetermined voltage to output the predetermined voltage. The smoothing capacitor is coupled to the output terminal. The second power supply circuit outputs a predetermined voltage or current to the output terminal via the smoothing capacitor, based on a feedback signal corresponding to the predetermined output voltage.

Abstract: A power supply apparatus of the present invention has an input terminal and an output terminal, and converts an input voltage at the input terminal into a predetermined output voltage at the output terminal. The power supply apparatus includes first and second power supply circuits and a smoothing capacitor. The first power supply circuit is coupled between the input terminal and the output terminal, and converts the input voltage into a predetermined voltage to output the predetermined voltage. The smoothing capacitor is coupled to the output terminal. The second power supply circuit outputs a predetermined voltage or current to the output terminal via the smoothing capacitor, based on a feedback signal corresponding to the predetermined output voltage.

Abstract: A step up/down switching regulator converts an input voltage of an input terminal into a predetermined setting voltage in a step up/down manner and outputs the setting voltage as an output voltage from an output terminal. The step up/down switching regulator includes a bypass mode in which the input voltage is directly bypassed to the output terminal without performing a step up/down switching, and a step up/down switching mode in which the step up/down switching is performed. The step up/down switching regulator includes a step up/down output unit, a step up/down control unit, and a mode select terminal.

Abstract: A switching regulator including an output switch element; a rectification switch element; an oscillation circuit; an error amplifier circuit; a slope circuit; a first voltage comparison circuit; a second voltage comparison circuit; a one pulse generation circuit; a control circuit; and a backflow detection circuit, and a control method thereof suppress variations to be stabilized with respect to a target value of the load current for switching between a PWM control and a PFM control, and ensure the switching from the PFM control to the PWM control or from the PWM control to the PFM control even if various parameters including external elements such as chips, coils, and capacitors vary.

Abstract: A switching regulator includes a first switching element and a second switching element in a pair to be switched over to convert an input voltage to a certain constant voltage, and an operation monitor to monitor an operation state of the first switching element, in which a switching of the second switching element is changed according to a result of the monitoring by the operation monitor.

Abstract: A switching power supply device includes a first control circuit that turns a first switch on when first and second switches are off and a voltage at a junction node therebetween is increased to decrease a voltage across the first switch to a first threshold voltage, turns off when a first ON-period has elapsed from when the first switch is turned on, and lengthens the first ON-period as an output voltage decreases relative to a reference voltage; and a second control circuit that turns the second switch on when both switches are off and a voltage across the second switch is decreased to a second threshold voltage, turns off when a reverse current flows through the inductor, sufficient to increase the voltage at the junction node to decrease the voltage across the first switch to the first threshold voltage after the second switch is turned off.

Abstract: A trimming circuit, installed in a semiconductor integrated circuit that has multiple different target values, the trimming circuit to adjusts circuit characteristics of the semiconductor integrated circuit to make output values of the semiconductor integrated circuit correspond to multiple desired target values and includes a setting-value table memory to store multiple setting value groups respectively containing different combinations of multiple setting values related to the multiple target values; a trimming cell circuit to store first selection information indicating one group of the multiple setting-value groups stored in the setting-value table memory; and a selector to select one group from the multiple setting-value group stored in the setting-value table memory based on the first selection information, and select one setting value from multiple setting values in the selected setting-value group based on external second selection information to output the selected setting value.

Abstract: An electronic device includes a current source for applying current, a pull-up resistor or a pull-down resistor configured to be connected to one of a plurality of data terminals, a voltage level detection circuit configured to detect voltage values of the plurality of data terminals, and a connected device determination circuit configured to determine a type of a power source device based on the voltage values of the plurality of data terminals detected by the voltage level detection circuit.

Abstract: A signal transmitting-receiving circuit includes a first circuit including a first MOS transistor having a gate and a drain, a second MOS transistor having a gate and a drain connected to the gate and drain of the first MOS transistor, and a source connected to ground, and a transmitting terminal transmitting a signal connected to the drains of the first and second MOS transistors; and a second circuit including a receiving terminal receiving the signal transmitted from the transmitting terminal of the first circuit connected to the transmitting terminal, a third MOS transistor having a gate connected to the receiving terminal, a drain connected to a reference voltage generator circuit and a source connected to ground, a resistor connected between the third MOS transistor and the reference voltage generator circuit, and an output terminal connected between the resistor and the third MOS transistor.

Abstract: A switching regulator including an output switch element; a rectification switch element; an oscillation circuit; an error amplifier circuit; a slope circuit; a first voltage comparison circuit; a second voltage comparison circuit; a one pulse generation circuit; a control circuit; and a backflow detection circuit, and a control method thereof suppress variations to be stabilized with respect to a target value of the load current for switching between a PWM control and a PFM control, and ensure the switching from the PFM control to the PWM control or from the PWM control to the PFM control even if various parameters including external elements such as chips, coils, and capacitors vary.

Abstract: A voltage monitor semiconductor device to monitor voltages of multiple rechargeable devices to output a detection result signal to indicate overcharge, over-discharge, or excess-current, the voltage monitor semiconductor device including multiple voltage input terminals, corresponding to the multiple rechargeable devices, to monitor the voltages of the corresponding rechargeable devices as monitor voltages; and a test signal generation circuit to generate a first test signal that inverts when at least one of the monitor voltages falls below a predetermined first threshold voltage that is not used normally as an abnormal state.

Abstract: A secondary cell protection circuit configured to protect plural secondary cells connected in series is disclosed that includes plural switching parts configured to be connected in parallel with the secondary cells respectively; and a charge controller configured to turn on the switching part connected to the secondary cell of which cell voltage is greater than or equal to a return voltage, and to turn off the switching part when all cell voltages of the secondary cells become greater than or equal to the return voltage, when the secondary cells are being charged.