Abstract: In a configuration of a complex resonance type switching converter provided with a voltage resonance type converter on the primary side and a parallel resonant circuit or a series resonant circuit on the secondary side, control of voltage obtained at a secondary winding and control for constant voltage on the secondary side are achieved by providing an active clamp circuit on the secondary side. The switching frequency of the circuit is constant. Thus, products having low withstand voltage may be selected as components such as a switching device and a resonant capacitor to be provided on the secondary side of the power supply circuit. In addition, it is possible to simplify configuration for constant-voltage control.

Abstract: A switching power supply circuit formed by providing a complex resonance type converter with a power factor improving circuit feeds back a voltage resonance pulse voltage generated in a primary-side voltage resonance converter to fast recovery type diodes via a tertiary winding or the tertiary winding and a series resonant capacitor by magnetic coupling to thereby improve a power factor to 0.9, and achieves an improvement in AC/DC conversion efficiency and a reduction in a ripple component of a direct-current output voltage by voltage doubler rectifier operation. Also, a first rectifier circuit and a second rectifier circuit shunt the current to be stored in a smoothing means, so that a range of zero volt switching operation is not narrowed even when the power factor is improved.

Abstract: A high voltage stabilizing circuit according to the present invention has a voltage resonance type converter as a switching converter that performs switching operation using direct-current input voltage obtained from commercial alternating-current power, and switching output of the voltage resonance type converter is directly transmitted to a primary winding of a flyback transformer FBT (high voltage output transformer). Then, a rectifier circuit for high voltage connected on the secondary side of the flyback transformer FBT provides high direct-current voltage as an anode voltage for a CRT, for example. The high direct-current voltage is stabilized by controlling the switching frequency of the voltage resonance type converter on the primary side according to the level of the high direct-current voltage. This configuration requires only one switching converter to be provided on the primary side of the flyback transformer FBT.

Abstract: Instead of inputting a horizontal deflection output pulse, a resonance voltage V2 outputted from the secondary side of an isolation converter transformer PIT forming a switching power supply circuit of the complex resonance type is inputted to the primary side of a flyback transformer FBT via a series resonant capacitor C3. Then, a resonance voltage V4 having a substantially sinusoidal waveform generated in the primary winding N4 of the flyback transformer FBT is stepped up to thereby provide a high direct-current voltage EHV having a specified high voltage level. Thus, it is possible to improve power conversion efficiency and reduce power loss. Also, by inducing a resonance voltage having a substantially sinusoidal waveform on the secondary side of the flyback transformer, the conduction angle of a rectifier diode is widened, and variation in the high direct-current voltage can be suppressed even when the load is varied.

Abstract: An active clamp circuit is provided on the primary side of a composite resonance type switching converter which has a voltage resonant converter on its primary side and a parallel resonance circuit on its secondary side, wherein a parallel resonance voltage pulse generated across a primary parallel resonance capacitor is clamped so that the level thereof is suppressed. Consequently, the withstand voltage requisite relative to any of the component elements such as switching elements and the primary parallel resonance capacitor employed in the power circuit can be selectively lowered.

Abstract: A switching power supply circuit has an insulated converter transformer with a gap for a loose coupling. on the secondary side, a parallel resonant capacitor is connected parallel to a secondary winding, and a full-wave rectification circuit produces a secondary-side DC output voltage for increasing a maximum load power. On the primary side, an ordinary full-wave rectification circuit, rather than a voltage doubler rectifying circuit, inputs a rectified and smoothed voltage having a level corresponding to the level of an AC input voltage. A constant-voltage control circuit system for stabilizing a secondary output voltage varies a switching frequency depending on the level of the secondary output voltage to perform composite control over a resonant impedance of a primary parallel resonant circuit and a conduction angle of the switching element.

Abstract: In a configuration of a complex resonance type switching converter provided with a voltage resonance type converter on the primary side and a parallel resonant circuit or a series resonant circuit on the secondary side, control of voltage obtained at a secondary winding and control for constant voltage on the secondary side are achieved by providing an active clamp circuit on the secondary side. The switching frequency of the circuit is constant. Thus, products having low withstand voltage may be selected as components such as a switching device and a resonant capacitor to be provided on the secondary side of the power supply circuit. In addition, it is possible to simplify configuration for constant-voltage control.

Abstract: An active clamp circuit is provided on the primary side of a complex resonance type switching converter having a parallel resonant circuit on the primary side and a parallel resonant circuit or a series resonant circuit on the secondary side. The active clamp circuit clamps a parallel resonance voltage pulse generated across a primary-side parallel resonant capacitor to thereby lower the level of the parallel resonance voltage pulse. Thus, withstand voltage of components such as switching devices and the primary-side parallel resonant capacitor can be lowered.

Abstract: The present invention relates to a switching power-supply circuit comprising: rectifying and smoothing means for generating a rectified and smoothed voltage and outputting the rectified and smoothed voltage as a direct-current input voltage; an insulating converter transformer for transferring a primary-side output to a secondary side; switching means for intermittently passing on the direct-current input voltage to a primary winding of the insulating converter transformer; a primary-side resonance circuit translating an operation of the switching means into voltage resonance; power-factor improvement means for improving a power factor by generating intermittently a rectified current based on the fed-back switching output voltage; a secondary-side resonance circuit on a secondary side of the insulating converter transformer; direct-current output voltage generation means carrying out a rectification operation in order to generate a secondary-side direct-current output voltage; and constant-voltage control mea

Abstract: A switching power supply circuit is disclosed which maintains a power factor which can satisfy actual use conditions against a variation in load or ac input voltage. The switching power supply circuit includes a power factor improvement circuit for a composite resonance converter and is constructed such that a switching output obtained by voltage division by a primary side resonance capacitor formed from a series connection of first and second capacitors is fed back to the power factor improvement circuit.

Abstract: An active clamp circuit is provided on the primary side of a composite resonance type switching converter which has a voltage resonant converter on its primary side and a parallel resonance circuit on its secondary side, wherein a parallel resonance voltage pulse generated across a primary parallel resonance capacitor is clamped so that the level thereof is suppressed. Consequently, the withstand voltage requisite relative to any of the component elements such as switching elements and the primary parallel resonance capacitor employed in the power circuit can be selectively lowered.

Abstract: A high voltage stabilizing circuit according to the present invention has a voltage resonance type converter as a switching converter that performs switching operation using direct-current input voltage obtained from commercial alternating-current power, and switching output of the voltage resonance type converter is directly transmitted to a primary winding of a flyback transformer FBT (high voltage output transformer). Then, a rectifier circuit for high voltage connected on the secondary side of the flyback transformer FBT provides high direct-current voltage as an anode voltage for a CRT, for example. The high direct-current voltage is stabilized by controlling the switching frequency of the voltage resonance type converter on the primary side according to the level of the high direct-current voltage. This configuration requires only one switching converter to be provided on the primary side of the flyback transformer FBT.

Abstract: The present invention relates to a switching power-supply circuit comprising: rectifying and smoothing means for generating a rectified and smoothed voltage and outputting the rectified and smoothed voltage as a direct-current input voltage; an insulating converter transformer for transferring a primary-side output to a secondary side; switching means for intermittently passing on the direct-current input voltage to a primary winding of the insulating converter transformer; a primary-side resonance circuit for actuating the switching means in a voltage resonance mode; power-factor improvement means for improving a power factor by generating intermittently a rectified current based on the fed-back switching output voltage; a secondary-side resonance circuit on a secondary side of the insulating converter transformer; direct-current output voltage generation means carrying out a rectification operation in order to generate a secondary-side direct-current output voltage; and constant-voltage control means for ex

Abstract: As a secondary side resonant circuit, a secondary side parallel resonant circuit and a secondary side series resonant circuit are combined to a secondary winding of an insulating converter transformer to form a secondary side resonant circuit. By this, the constant voltage control of a secondary side DC output voltage is made the combined control of controlling a switching frequency and a conduction angle of a switching current flowing through a switching element, so that enlargement of a period in which the switching element is turned off is suppressed.

Abstract: A switching power supply circuit of current-resonance type with the capability of power factor improvement includes a filter capacitor (C.sub.N) connected between the positive and negative output terminals of the rectifier, a filter choke coil (L.sub.N) and fast-recovery diode (D.sub.2) connected in series to cut in on the rectifier output line, and a resonant capacitor (C.sub.2) which forms a resonant circuit in unison with the filter choke coil. The output of a series resonant circuit (C.sub.1,N.sub.1) on the primary side is superimposed on the rectifier output so that the power factor is improved, thereby eliminating the need of a choke coil (CH). The circuit accomplishes the more compact, light-weight and low-cost design, and improves the power conversion efficiency.

Abstract: To improve the power conversion efficiency of a power circuit provided with a power-factor improvement converter and reduce the size, weight, and cost of the circuit, the power-factor improvement converter according to the invention is provided at a stage in front of the switching power circuit, in which a self-excited current resonant switching converter with a simple circuit construction is provided and the switching voltage thereof is fed back to the rectifying path via series resonant circuits so as to improve the power factor.

Abstract: To improve the power conversion efficiency of a power circuit provided with a power-factor improvement converter and reduce the size, weight, and cost of the circuit, the power-factor improvement converter according to the invention is provided at a stage in front of the switching power circuit, in which a self-excited current resonant switching converter with a simple circuit construction is provided and the switching voltage thereof is fed back to the rectifying path via series resonant circuits so as to improve the power factor.

Abstract: A current resonance type switching power circuit includes a rectifying circuit for rectifying commercial power, a smoothing circuit having a choke coil and a smoothing capacitor for smoothing the output of the rectifying circuit, a switching circuit unit for rendering intermittent the voltage output from the smoothing circuit, and a resonance circuit which includes a primary winding of an insulation transformer and a resonance capacitor and is supplied with a switching output of the switching circuit unit, wherein the resonance circuit is connected to a line between the rectifying circuit and the smoothing circuit so that the resonance output thereof is superposed on the choke coil.

Abstract: A switching power source apparatus for producing power signals. The apparatus includes a rectification circuit for rectifying received alternating voltage signals, a smoothing circuit for smoothing the rectified signals and a switching power supply circuit for producing the power signals. The apparatus may include a circuit for extracting low voltage signals from the switching power supply circuit and for superposing such low voltage signals on the smoothed rectified signals so as to reduce a ripple component present in the smoother rectified signals. The smoothing circuit and the switching power supply circuit may utilize a common switching device and/or a common frequency switching signal.

Abstract: A power supply circuit securing a stabilized output DC voltage despite increases in the input DC voltage, uses an economical electromagnetic relay, in which a control current Ic' is supplied from a switching amplifier 1 to a control winding Nc' of a saturable ferrite transformer (CDT'). A class A amplifier formed of resistors R.sub.1 to R.sub.3 and a transistor Q.sub.8 of the switching amplifier 1 amplifies a DC input voltage E1 and controls the switching frequency ranging from 100 to 200 KHz according to input DC voltage ranging from 10 to 32V. Resistors R.sub.4 and R.sub.5 and a transistor Q.sub.7 for the switching amplifier 1 form a switching circuit of the control current Ic', while resistors R.sub.6 and R.sub.7 and a transistor Q.sub.8 form a switching circuit for the starting currents of switching transistors Q.sub.1 and Q.sub.3 of a first and a third half-bridge resonant converter.