Abstract: An improved gate drive circuit powered by a DC source voltage, the drive circuit having an isolated output stage with a parallel-connected by-pass capacitor and a switched input capacitor circuit that maintains a charge on the by-pass capacitor for driving the gate of a controlled MOS transistor while isolating the by-pass capacitor from the source voltage. In a fully isolated embodiment of the improved gate drive circuit, a bank of controlled switches alternately couples the input capacitor to the source voltage and the by-pass capacitor, while in another embodiment, uni-directional isolation is achieved by replacing one or more of the controlled switches with diodes.

Abstract: An improved motor vehicle electrical system includes a flexible topology DC-to-DC converter for coupling an engine-driven alternator to vehicle electrical loads at a mode-dependent transfer ratio. The output voltage of the alternator is regulated based the load voltage, and the converter is operable in one of a number of different modes based on engine speed, including a forward boost mode, a forward unity mode, and a forward buck mode. In the forward boost mode, the converter output voltage is boosted above that of the alternator to enable battery charging at low engine speeds; in the forward unity mode, the alternator output voltage is transferred to the battery and electrical loads at a unity transfer ratio; and in the forward buck mode, the converter output voltage is reduced below that of the alternator to enhance the alternator power output at medium-to-high engine speeds.

Abstract: An improved low-cost gate drive circuit drives the bridge transistors of a multiple power supply bridge circuit with a single logic level voltage. In general, the single logic level voltage is referenced to a first power supply and provides gate drive voltages for bridge transistors associated with a second power supply. The logic level voltage is bootstrapped to a first by-pass capacitor to provide a first gate drive voltage for a high-side transistor associated with the first power supply, and the charge on the first by-pass capacitor is consecutively bootstrapped to second and third by-pass capacitors to provide second and third gate drive voltages for bridge transistors associated with the second power supply.

Abstract: An AC/DC harmonic neutralizing power converter. The power converter includes a first rectifier, load output terminals for delivering DC power to a load, and a harmonic neutralizing converter. The first rectifier includes an input to receive AC input power and an output. The harmonic neutralizing converter comprises a power switching inverter and a second rectifier. The power switching inverter includes an input connected to the output of the first rectifier, an LC resonant circuit comprising a series connected capacitor and inductor, and an output. The second rectifier of the harmonic neutralizing converter has an input connected to the output of the inverter and an output connected in voltage additive relationship to the output of the first rectifier. The added outputs of the rectifiers is connected to the load output terminals such that the output voltage on the load output terminals substantially equals the added output voltages of the rectifiers.

Abstract: An AC/DC harmonic neutralizing power converter. The power converter includes a first rectifier, load output terminals for delivering DC power to a load, and a harmonic neutralizing converter. The first rectifier includes an input to receive AC input power and an output. The harmonic neutralizing converter comprises a power switching inverter and a second rectifier. The power switching inverter includes an input connected to the output of the first rectifier, an LC resonant circuit, and an output. The second rectifier of the harmonic neutralizing converter has an input connected to the output of the inverter and an output connected in voltage additive relationship to the output of the first rectifier. The added outputs of the rectifiers is connected to the load output terminals such that the output voltage on the load output terminals substantially equals the added output voltages of the rectifiers.

Abstract: A multi-phase AC to DC harmonic neutralizing power converter. The power converter includes a plurality of inputs for respective phases of a multi-phase source of AC power and a plurality of first rectifiers connected respectively to the inputs. A multi-phase harmonic neutralizing converter includes a power switching inverter having an input connected to the outputs of each of the first rectifiers, the inverter including LC resonant circuits. A plurality of second rectifiers having respective inputs connected to the output of the inverter through a plurality of respective transformers having outputs that are connected in voltage additive relationship to the outputs of the respective individual phase first rectifiers. A single set of power switches is utilized to neutralize multiple input power phases.

Abstract: A three phase AC to DC voltage converter includes separate single phase AC to DC converters for each phase of a three phase source with the DC voltage output of the three converters paralleled and controlled to provide necessary regulation. Each of the single phase AC to DC converters includes a full-wave bridge rectifier feeding a substantially resistive load including an inverter and a second single phase full-wave bridge rectifier. To the extent that each inverter and second single phase full-wave bridge rectifier approximate a resistive load, the source current harmonics are reduced. Additionally, the triplen harmonics produced in the three phase source lines by each of the three AC to DC converters are cancelled by the triplen harmonics produced in the three phase source lines by the remaining two AC to DC converters.