Abstract: A discharge-lamp control device for lighting a discharge-lamp includes two electrodes, first and second driving units to supply power to the discharge-lamp through the electrodes, respectively. Each driving unit includes a transformer having primary and secondary coils and a capacitor connected in parallel to the secondary coil. The first driving unit has impedance characteristics with a minimum impedance at a first frequency and a maximum impedance at a second frequency lower than the first frequency. The second driving unit has impedance characteristics having a minimum impedance at a third frequency and a maximum impedance at a fourth frequency lower than the third frequency. The first frequency is set to be higher than the third frequency. The second frequency is set to be lower than the fourth frequency. An operating frequency of the driving circuit is selected within a frequency bandwidth from the fourth frequency to the third frequency.

Abstract: A selector sets respective phases of pulse driving signals in reverse when a proportion signal or integration signal does not exceed a threshold. Shifting the respective phases of the pulse driving signals from each other lowers the ripple voltage. When the load current increases drastically, the output voltage Vo tends to decrease remarkably because of the shortage of capacity in the power supply. In this case, when the proportion signal or integration signal exceeds its corresponding threshold, a phase control unit causes the pulse driving signals to synchronize their phases, i.e., the selector supplies the same ramp wave to the comparators, so that respective output voltages supplied from the DC voltage converter circuits attain the same phase, thereby restraining the output voltage supplied to the load from decreasing remarkably.

Abstract: A controller 7A for generating a drive signal (PWM signal) PS for controlling a switching power supply, comprises control signal setting means 10, 11 for setting a control signal CS on the basis of an output voltage Vo and a target voltage Vr; current estimating means 12 for estimating an inductor current on the basis of the drive signal PS and for generating an estimated current signal PC; DC component removing means 14, 15 for extracting a DC component DC included in the estimated current signal PC and for removing the DC component DC from the estimated current signal PC; DC component resetting means 13, 14 for resetting the extracted DC component DC every predetermined time; and comparing means 16 for comparing the control signal CS with the estimated current signal PC? after the removal of the DC component DC.

Abstract: An output voltage of a switching power supply is regulated to a target value. When the target value of the output voltage is altered, the reference value is changed monotonously and linearly a plurality of times at a plurality of gradients to the altered target value. An input voltage of the power supply is switched in response to a switching pulse with the duty ratio calculated according to a difference between the reference value and the output voltage.

Abstract: A discharge-lamp control device for lighting a discharge-lamp includes two electrodes, first and second driving units to supply power to the discharge-lamp through the electrodes, respectively. Each driving unit includes a transformer having primary and secondary coils and a capacitor connected in parallel to the secondary coil. The first driving unit has impedance characteristics with a minimum impedance at a first frequency and a maximum impedance at a second frequency lower than the first frequency. The second driving unit has impedance characteristics having a minimum impedance at a third frequency and a maximum impedance at a fourth frequency lower than the third frequency. The first frequency is set to be higher than the third frequency. The second frequency is set to be lower than the fourth frequency. An operating frequency of the driving circuit is selected within a frequency bandwidth from the fourth frequency to the third frequency.

Abstract: An adder 11 outputs a signal VS indicating a value of (Vr?Vo), and a multiplier 12 outputs a control signal GS indicating a value of G(Vr?Vo) on the basis of the signal VS. An adder 13 outputs a signal HS on the basis of the control signal GS and a signal FS outputted from an operation circuit 30, and a PWM signal generating circuit 20 generates a PWM signal KS on the basis of the signal HS and a ramp signal RS outputted from a ramp signal circuit 15, and outputs this signal KS to a switching power supply. A counter 14 counts an on time of the PWM signal KS and retains a count value at a time of receiving a sample signal SMP. The operation circuit 30 has a high-pass filter 31 and an integrator 32, performs an operation based on a signal DS indicating the count value outputted from the counter 14, and outputs the signal FS after the operation.

Abstract: A controller 7A for generating a drive signal PS for switching control of a switching element in a switching power supply, includes a duty ratio generator 10, 11 for detecting a duty ratio D of the drive signal PS for controlling the switching element of the switching power supply, and generating a signal corresponding to the duty ratio; a control signal generator 13, 14 for generating a control signal CS on the basis of a difference between a target voltage VREF in the switching power supply and an output voltage Vo detected in the switching power supply; an operation unit 15 for generating a signal corresponding to a product of the signal corresponding to the duty ratio, and the control signal CS; and a drive signal generator 16, 17 for generating the drive signal PS on the basis of the signal generated by the operation unit 15.

Abstract: An output voltage of a switching power supply is regulated to a target value. When the target value of the output voltage is altered, the reference value is changed monotonously and linearly a plurality of times at a plurality of gradients to the altered target value. An input voltage of the power supply is switched in response to a switching pulse with the duty ratio calculated according to a difference between the reference value and the output voltage.

Abstract: A controller 7A for generating a drive signal PS for switching control of a switching element in a switching power supply, includes a duty ratio generator 10, 11 for detecting a duty ratio D of the drive signal PS for controlling the switching element of the switching power supply, and generating a signal corresponding to the duty ratio; a control signal generator 13, 14 for generating a control signal CS on the basis of a difference between a target voltage VREF in the switching power supply and an output voltage Vo detected in the switching power supply; an operation unit 15 for generating a signal corresponding to a product of the signal corresponding to the duty ratio, and the control signal CS; and a drive signal generator 16, 17 for generating the drive signal PS on the basis of the signal generated by the operation unit 15.

Abstract: A selector sets respective phases of pulse driving signals in reverse when a proportion signal or integration signal does not exceed a threshold. Shifting the respective phases of the pulse driving signals from each other lowers the ripple voltage. When the load current increases drastically, the output voltage Vo tends to decrease remarkably because of the shortage of capacity in the power supply. In this case, when the proportion signal or integration signal exceeds its corresponding threshold, a phase control unit causes the pulse driving signals to synchronize their phases, i.e., the selector supplies the same ramp wave to the comparators, so that respective output voltages supplied from the DC voltage converter circuits attain the same phase, thereby restraining the output voltage supplied to the load from decreasing remarkably.

Abstract: An adder 11 outputs a signal VS indicating a value of (Vr−Vo), and a multiplier 12 outputs a control signal GS indicating a value of G(Vr−Vo) on the basis of the signal VS. An adder 13 outputs a signal HS on the basis of the control signal GS and a signal FS outputted from an operation circuit 30, and a PWM signal generating circuit 20 generates a PWM signal KS on the basis of the signal HS and a ramp signal RS outputted from a ramp signal circuit 15, and outputs this signal KS to a switching power supply. A counter 14 counts an on time of the PWM signal KS and retains a count value at a time of receiving a sample signal SMP. The operation circuit 30 has a high-pass filter 31 and an integrator 32, performs an operation based on a signal DS indicating the count value outputted from the counter 14, and outputs the signal FS after the operation.

Abstract: A controller 7A for generating a drive signal (PWM signal) PS for controlling a switching power supply, comprises control signal setting means 10, 11 for setting a control signal CS on the basis of an output voltage Vo and a target voltage Vr; current estimating means 12 for estimating an inductor current on the basis of the drive signal PS and for generating an estimated current signal PC; DC component removing means 14, 15 for extracting a DC component DC included in the estimated current signal PC and for removing the DC component DC from the estimated current signal PC; DC component resetting means 13, 14 for resetting the extracted DC component DC every predetermined time; and comparing means 16 for comparing the control signal CS with the estimated current signal PC′ after the removal of the DC component DC.

Abstract: A switching power source having a digital control system is provided. The switching power source includes a switching circuit 40 for switching an input power, an output circuit 50 for converting the switching output into a DC output, and a digital control 70. The digital control 70 is adapted to receive an output voltage analog signal AS1 and an output current analog signal AS2, and to convert the signals AS1 and AS2 into digital signals. It further functions to calculate, based on the digital signals, a command value for determining at least one of the switching frequency and the on or off time of the main switch 42. The operation of the main switch 42 is controlled in accordance with the command value. Information on power source input voltage or load terminal voltage is obtained through an assumption based on the signals AS1 and AS2.

Abstract: A switching power source having a digital control system is provided. The switching power source includes a switching circuit 40 for switching an input power, an output circuit 50 for converting the switching output into a DC output, and a digital control 70. The digital control 70 is adapted to receive an output voltage analog signal AS1 and an output current analog signal AS2, and to convert the signals AS1 and AS2 into digital signals. It further functions to calculate, based on the digital signals, a command value for determining at least one of the switching frequency and the on or off time of the main switch 42. The operation of the main switch 42 is controlled in accordance with the command value. Information on power source input voltage or load terminal voltage is obtained through an assumption based on the signals AS1 and AS2.