Isolation transformer

About: Isolation transformer is a research topic. Over the lifetime, 8145 publications have been published within this topic receiving 72396 citations.

Isolated switched-boost push–pull DC–DC converter for step-up applications

Abstract: A high voltage ratio DC–DC converter is proposed which is comprised of four stages. First, an impedance network along with a switching network have been used to boost the input voltage. The boosted voltage waveform is then followed by an isolation transformer to provide another degree of freedom and obtain higher boost ability. Finally, a voltage multiplier rectifier is utilised to rectify the secondary voltage of the transformer. No switching dead‐time is required, which increases the reliability of the converter. The proposed converter benefits from the continuous input current. Besides, a comparison with the existing step‐up topologies indicates that the number of passive elements and hence the weight and size have been reduced. The operating principles were analysed and the experimental tests on a 260 W prototype reveal that a high efficiency above 91% can be achieved.

Boost rectifier with half-power rated semiconductor devices

Abstract: A rectifier has two half-controlled bridge rectifiers which are connected in parallel to provide DC power to DC bus lines. Each bridge rectifier receives AC power through inductances such as series inductors or an isolation transformer with a single primary and two secondaries. Each bridge rectifier has a full bridge of diodes, with active switching devices connected in parallel with half of the diodes in the bridge. The switching devices can be controlled to provide unity power factor at the AC input lines, allowing lower rated diodes and switching devices to be used.

MOSFET fullbridge switching regulator having transformer coupled MOSFET drive circuit

Abstract: An FET full bridge regulator has a driving transformer for the gates of the power FETs of the regulator, and a driving circuit for the primary of the driving transformer, the driving circuit including a full bridge formed by first and second sets of driving FETs, each set formed by a complementary pair of FETs and being connected across the transformer, primary, one FET of each set being driven ON to together form a series of conducting paths across the primary of the transformer in the absense of driving signals. The voltage supply for the driving FETS in the driving circuits of the primary of the driving transformer includes a resistance across which there is developed a voltage proportional to the current drawn by the driving transformer primary in each half cycle of its operation for reducing imbalance between the half cycles.

Active snubber for buck-based converters and method of operation thereof

Abstract: For use with a buck-based converter having an isolation transformer, a snubber circuit and a method of damping a transient in the power rectifying diode due to its reverse recovery. In one embodiment, the snubber circuit includes: (1) a capacitor, coupled to a power rectifying diode in the buck-based converter, that receives energy from the power rectifying diode during a reverse recovery period thereof and (2) a flyback converter, coupled to the capacitor, that receives the energy from the capacitor and delivers the energy to a voltage source on the primary side of the isolation transformer.

Constant power switching power supply

Abstract: A power supply for a gaseous discharge lamp in which power adjustments are made automatically to insure that rated lamp power is delivered regardless of changes in lamp impedance or line voltage which may occur. A high D.C. voltage is delivered to a step down low hysteresis transformer and electronic switching is provided to obtain a high frequency pulsed flow to the primary of the transformer. Sawtooth waves are generated and peak current is utilized to regulate closely power input to the transformer. A feature is the use of a programming resistor to select the desired power level for the particular gas discharge lamp.