Abstract: Aspects of the disclosure relate generally to uninterruptible power supply (“UPS”) units for systems requiring back up power. The UPS units include circuitry for controlling charging and allowing discharging of a battery. The circuitry includes a controller as well as a pair of metal-oxide semiconductor field effect transistors (“MOSFET”) switches. The pair of MOSFET switches includes a charging and a discharging MOSFET switches in series with the battery operating as a bidirectional switch. A UPS unit may be charged and subsequently stored for period of time. During this time, plurality of features may prevent current leakage from the batteries. For example, PNP bipolar transistors and additional MOSFET switches may be used to prevent current leakage. These features alone or in combination may allow for long term storage of the uninterruptible power supply units without current leakage.

Abstract: Aspects of the disclosure relate generally to uninterruptible power supply (“UPS”) units for systems requiring back up power. The UPS units include driving circuitry for controlling charging and allowing discharging of a battery. The driving circuitry includes a controller as well as a pair of switches. The MOSFETs includes a charging and a discharging MOSFET in series with the battery operating as a bidirectional switch. When the UPS unit is connected to an AC power supply, the controller regulates the current through the charging MOSFET switch based on feedback from a feedback device in order to charge the battery. If AC power is lost, the controller goes into saturation, switching the discharging MOSFET to a on condition and allowing the battery to discharge. The transitions from AC to battery power and vice versa are automatically achieved via the controller.

Abstract: Aspects relate to utilizing power factor correction to compensate for a leading power factor produced mainly due to electromagnetic interference (EMI) capacitors in front of a power factor correction stage. Provided is a power supply that includes a power factor correction circuit that includes a second harmonic generator component. The harmonic generator component includes a filter component and an integrator component. The filter component is configured to receive a rectified voltage and a power factor correction current and block a direct current component. The integrator component is configured to receive an alternating current component from the filter component and produce a harmonic that causes an angle of the power factor correction current to change from a leading power factor to a unity power factor or to a lagging power factor.

Abstract: Systems and methods for reliable and efficient hot swap control are disclosed herein. The system includes a feedback circuit that senses a load voltage and enables a gate driver, in response to a difference between input and output voltages falling below a predefined threshold value. Once enabled, the gate driver instantaneously, or almost instantaneously, turns on a set of paralleled metal-oxide-semiconductor field-effect transistors (MOSFETs) in a hot swap control circuit and/or enables a load. Since the MOSFETs are switched instantaneously, or almost instantaneously, they do not operate in a linear mode and thus reliable sharing of load current is achieved. In addition, on detecting an overcurrent condition, the gate driver is disabled, which in turn switches off the MOSFETs. Accordingly, both inrush current limiting and overcurrent protection can be provided.

Abstract: Systems and methods for efficient three-phase auxiliary power supply for low power applications are disclosed herein. The system includes a capacitor divider circuit that can leverage electromagnetic interference (EMI) filter capacitors utilized in a main power converter. Further, three low voltage capacitors, connected in a star configuration (for a three-phase four-wire input) or a delta connection (for a three-phase three-wire input), can be utilized in the capacitor divider circuit. Additionally or alternatively, multiple high voltage capacitors can be paralleled. The capacitor divider circuit generates a low voltage alternate current (AC) signal that can be converted to a corresponding low voltage direct current (DC) signal by employing a rectifier circuit. Due to the three-phase input, the output DC signal has a very low output ripple voltage.

Abstract: Methods and apparatus are disclosed for balancing currents passing through multiple parallel circuit branches and in some cases through parallel fluorescent lamps. Single transformers with multiple-leg magnetic cores are wound in specific manners that simplify current balancing. Conventional three-legged EE-type magnetic cores, with disclosed windings are used to balance current in circuits with three or more parallel branches, such as parallel connected Cold Cathode Fluorescent Lamps (CCFLs).

Abstract: Methods and apparatus are disclosed for balancing currents passing through multiple circuit loads and in some cases through fluorescent lamps. Multiple-leg magnetic cores are wound in specific manners to simplify current balancing. Conventional three- or more than three-legged EE- and EI-type magnetic cores, with disclosed windings are used to balance current in circuits with multiple branches, such as connected Cold Cathode Fluorescent Lamps (CCFLs).

Abstract: Methods and apparatus are disclosed for balancing currents passing through multiple parallel circuit branches and in some cases through parallel fluorescent lamps. Single transformers with multiple-leg magnetic cores are wound in specific manners that simplify current balancing. Conventional three-legged EE-type magnetic cores, with disclosed windings are used to balance current in circuits with three or more parallel branches, such as parallel connected Cold Cathode Fluorescent Lamps (CCFLs).

Abstract: Embodiments of isolated gate driver circuits are disclosed for driving high- and low-side switching devices for half- and full-bridge power converter topology. Disclosed circuits provide sufficient dead-time, operate over a wide range of duty cycles, and require a single power supply (Vcc). Typical applications for such circuits include cold cathode fluorescent lamp (CCFL) inverters that are powered by a high voltage DC rail.

Abstract: Embodiments of isolated gate driver circuits are disclosed for driving high- and low-side switching devices for half- and full-bridge power converter topology. Disclosed circuits provide sufficient dead-time, operate over a wide range of duty cycles, and require a single power supply (Vcc). Typical applications for such circuits include cold cathode fluorescent lamp (CCFL) inverters that are powered by a high voltage DC rail.

Abstract: A DC to DC converter including a zigzag transformer. The transformer operates at high frequency with integrated magnetics and does not provide isolation. The multiphase converter has gate inputs with PWM signals appropriately phase-shifted depending on the number of phases to make balanced phase voltages across the transformer windings. The switching frequency of the converter is relatively low but fast transient response can be achieved by adding an integrated zigzag transformer.

Abstract: Methods and apparatus are disclosed for balancing currents passing through multiple parallel circuit branches and in some cases through parallel fluorescent lamps. Single transformers with multiple-leg magnetic cores are wound in specific manners that simplify current balancing. Conventional three-legged EE-type magnetic cores, with disclosed windings are used to balance current in circuits with three or more parallel branches, such as parallel connected Cold Cathode Fluorescent Lamps (CCFLs).

Abstract: Methods and apparatus are disclosed for balancing currents passing through multiple circuit loads and in some cases through fluorescent lamps. Multiple-leg magnetic cores are wound in specific manners to simplify current balancing. Conventional three- or more than three-legged EE- and EI-type magnetic cores, with disclosed windings are used to balance current in circuits with multiple branches, such as connected Cold Cathode Fluorescent Lamps (CCFLs).

Abstract: Methods and apparatus are disclosed for balancing currents passing through multiple parallel circuit branches and in some cases through parallel fluorescent lamps. Single transformers with multiple-leg magnetic cores are wound in specific manners that simplify current balancing. Conventional three-legged EE-type magnetic cores, with disclosed windings are used to balance current in circuits with three or more parallel branches, such as parallel connected Cold Cathode Fluorescent Lamps (CCFLs).

Abstract: A DC to DC converter comprising a zigzag transformer is provided. The transformer operates at higher frequency with integrated magnetics and does not provide isolation. The multiphase converter has gate inputs with PWM signals appropriately phase-shifted depending on the number of phases to make balanced phase voltages across the transformer windings. The switching frequency of the converter is slightly lower but fast transient response can be achieved by adding an integrated zigzag transformer. The disclosed converter improves overall efficiency, reduces current ripple and simplifies current control.