Abstract: An inductor design having a detection winding which is magnetically coupled to the existing winding and its induction voltage is used to cancel that of the existing winding. Having the induction voltage cancelled, the voltage across the existing winding represents a resistive voltage drop of the existing winding current. The detection winding is furthermore built with a non-inductive portion having a significantly higher DC resistance in proportion to that of the existing winding. This resistance proportion is insensitive against temperature variations when both the existing and the detection windings are built with the same material and subjected to the same environment. A reference current is fed through the detection winding to produce a reference resistive voltage drop which is used to cancel the resistive voltage drop across the existing winding. When a precise cancellation occurs, the existing winding current is known to be in exact proportion to the reference current.

Abstract: The present invention discloses a single stage DC to DC electric power conversation circuit which has a transfer gain variable by pulse-width modulation over a continuum from zero to beyond unity. Conversion efficiency of the circuit is optimal when the transfer gain is set to its middle range, where a large part of power is transferred from input directly to output without undergone electro-magnetic conversion. Conversion efficiency is therefore very high and such a high efficiency occurs under normal operating condition.

Abstract: Described is an inverter device suitable for driving a cold cathode fluorescent lamp (CCFL), comprising a transformer having a primary winding and a secondary winding. The primary winding has two terminals connected to a return-path terminal of a direct current (DC) power source through a second switch and a third switch, respectively, and a center tap connected to an output of the DC power source through a first switch. A signal controlling unit is further included to control the switches in such a manner that the second and third switches are on concurrently or alternatively in cooperation with the first switch. As such, an alternating current (AC) power is fed to the primary winding of the transformer and an output of the transformer is supplied to the CCFL.

Abstract: A fine-turning circuit is used for adjusting the output voltage of a main transformer in an electrical power convert device and solving the problem of turns granularity of conventional transformers. The fine-turning circuit includes an auxiliary transformer having a primary coil and a secondary coil, and a voltage level clamper connected with the secondary coil of the auxiliary transformer via a diode. The primary coil of the auxiliary transformer is connected with the renovated winding in serial. When a current flows through the renovated winding, the secondary coil of the auxiliary transformer reacts to an amended voltage so as to amend the output voltage of the main transformer. The amended voltage is adjusted via changing the turn ratio of the primary coil to the secondary coil of the auxiliary transformer.

Abstract: A switching power conversion circuit comprises a saturable load assembly, a first switching inductance coil assembly and a second switching inductance coil assembly. The saturable load assembly is composed of a load and a saturable reactor. The first switching inductance coil assembly is connected to the saturable load assembly and a first potential. The second switching inductance coil assembly is magnetically coupled with the first switching inductance coil assembly, and is connected to the first switching inductance coil assembly and a second potential. When the first and second switching inductance coil assemblies are power switched, the saturation effect of the saturable reactor is exploited to let the terminal potential of the saturable reactor drop before switching, hence letting the terminal potential of the transfer switch be zero.