Abstract: A power converter apparatus includes an input port and an output port. First and second inductors are coupled to the output port. A first switching circuit is coupled to the input port and the first inductor. The first switching circuit is operative to repetitively perform a cycle including a first state in which the first switching circuit couples the first inductor to the input port such that energy is transferred from the input port to the first inductor, a second state in which the first switching circuit short circuits the first inductor, and a third state in which the first switching circuit decouples the first inductor such that energy is transferred from the first inductor to the output port. A second switching circuit is coupled to the input port and the second inductor and implements a similar cycle. The second switching circuit may operate such that the first and second states of the second switching circuit substantially coincide with the third state of the first switching circuit.

Abstract: A power converter apparatus includes a transformer having a primary winding and a secondary winding, a switching circuit operative to couple and decouple the primary winding of the transformer to a power source, and a control circuit that controls the switching circuit. A feedback circuit is coupled to the output port of a power transfer network and to the control circuit. The feedback circuit generates a current responsive to an output voltage at an output port of a power transfer network, charges a capacitance responsive to the generated current, and intermittently discharges the capacitance responsive to a control signal generated by the control circuit. A modulator circuit is coupled to the feedback circuit and to the power transfer network, and selectively couples the secondary winding of the transformer to an input port of the power transfer network responsive to a voltage on the capacitance. The invention may be embodied as apparatus or methods.

Abstract: A power conversion apparatus, e.g., a DC-to-DC converter, includes a transformer having primary and secondary windings. A first switching circuit has an input port configured to be coupled across a DC power source and an output port coupled to the primary winding of the transformer. A switch control circuit is operatively associated with the switching circuit and causes the switching circuit to alternately apply first and second polarity voltages to the primary winding. A second switching circuit is operative to transfer energy to a load from the secondary winding via a first capacitor responsive to application of the first polarity voltage to the primary winding and to transfer energy to the load from the secondary winding via a second capacitor responsive to application of the second polarity voltage to the primary winding. The first switching circuit may be operated such that switches therein may be operated under reduced current and/or reduced voltage conditions.

Abstract: The present invention relates to a method and apparatus for manufacturing a surface mount power supply device having effective thermal management. The surface mount power supply device comprises a printed circuit board mounted to a thermal plastic lead frame attach by means of vertically-extending aluminum pins embedded in the lead frame attach. A cylindrical member is centered within the lead frame attach by means of inwardly protruding arms transversely connected to the lead frame attach to allow for a pick-and-place operation.

Abstract: The present invention relates to a power supply device having an electromagnetic interference (“EMI”) suppression circuit connected to the input terminals. The EMI suppression circuit is mounted within the power supply device to ensure a low-impedance path to ground. Furthermore, the EMI suppression circuit can be quickly, easily and safely disconnected from ground without opening the power supply device.

Abstract: The present invention relates to a method and apparatus for manufacturing a surface mount power supply device having effective thermal management. The surface mount power supply device comprises a printed circuit board mounted to a thermal plastic lead frame attach by means of vertically-extending aluminum pins embedded in the lead frame attach. A cylindrical member is centered within the lead frame attach by means of inwardly protruding arms transversely connected to the lead frame attach to allow for a pick-and-place operation.

Abstract: A switch mode power converter having an overload protection system is disclosed. The system includes an input stage having an input voltage source. A switching circuit for coupling said input source to an output stage is provided. The output stage further includes a first filter circuit providing an output current to a load circuit. A second filter circuit is coupled to the output stage providing a voltage proportional to the output current and to internal temperature of the switch mode converter. An error amplifier responsive to the voltage derived by a second filter and a reference voltage, generates an error signal proportional to the difference of the voltage applied to the error amplifier. The error signal adjusts the operating parameters of the switching circuit.

Abstract: Adaptive control of converters is provided to achieve, in one case, a constant current characteristic by controlling input power as a function of the ratio of output voltage to output current. In another class of circuits, input current to the converter is controlled under an adaptive control arrangement in response to output voltage/output current ratios which may also be modified by input current or input voltage. The adaptive control may be augmented with low frequency negative feedback control loops.

Abstract: A DC converter system for providing an output voltage to a load, employing a pulse width modulated switching is disclosed. The system includes a DC input voltage source and a control switch having an ON period and an OFF period. The control switch during the ON period conducts a current responsive to the voltage source. A controller is provided to vary the ON period and the OFF period of the switch, such that the ON period is inversely proportional to the voltage source and the OFF period is inversely proportional to the output voltage.

Abstract: An electric power dissipation system operates as an active load for power supply testing. The system has a closed loop voltage to current converter with a first and second load terminal. A capacitance is connected across the first and second load terminals. A power supply having a first and second output terminal is coupled to the first and second load terminals via test conductors which have a first and second inductance respectively. A correction signal generator is provided to be responsive to the power supply. The correction signal generator provides an output signal as a function of the voltage generated across one of the inductances. A summing circuit responds to the output signal of the correction signal generator and also responds to a command signal. The output of the summing circuit controls the current flow of the current converter.

Abstract: A composite printed circuit board includes a metal substrate printed circuit section and an insulation substrate printed circuit board section. The metal substrate printed circuit section includes a first layer of a thermally conductive metal for providing high thermal conductivity, and a second layer made of a thermally conductive and electrically insulative material disposed adjacently to said first layer. The second layer has an upper surface upon which electrically conductive wiring may be disposed. The insulator substrate printed circuit board section forms an integral surface with the metal substrate printed circuit section. The insulator substrate printed circuit section further includes a first layer of insulative material, and a second layer of a metallic foil disposed adjacently to at least one side of said first layer of insulative material for forming a conductive wiring layout.

Abstract: An improved DC to DC converter is provided in particular for converters with high power density requirements. The converter comprises an input voltage source and a capacitor connected in series to the voltage source. A switching transistor configuration connects the voltage source and the capacitor alternatively to the primary windings of a transformer. The secondary windings of the transformer are connected to a full-wave rectifier and a filter. The output voltage provided at the output of the filter is modulated by a controlling means.

Abstract: A voltage detector to sense deviations of instantaneous value of a monitored voltage from a desired value is provided. The system includes a reference voltage source for providing a reference voltage. A divider responsive to the monitored voltage and the reference voltage divides the reference voltage by the monitored voltage. Thereafter a window comparator responsive to an output of the divider produces an indication when the output of the divider is either higher than some predetermined high value or lower than some predetermined low value.

Abstract: An apparatus is disclosed for maintaining accurate control of the maximum duty cycle generated by pulse width modulators. The output signal of a pulse width modulation comparator is averaged and compared to a reference value. This reference value is proportional to the peak value of the comparator's output voltage. A closed loop circuit continually adjusts the duty cycle so the difference between the reference value and the average comparator output is nulled thereby providing an accurate maximum duty cycle output.

Abstract: A high frequency self-oscillating inverter including a snubber circuit for minimizing both turn-on and turn-off switching losses. The inverter converts a DC supply to an AC load current and includes a saturating transformer for alternatively driving first and second switching devices during subsequent unsaturated states. During the time the transformer is saturated, both switching devices are kept off.The snubber circuit includes a first capacitor across the first switching device, a second capacitor across the second switching device, and an inductance. During saturation the two capacitors and inductance form a resonance circuit, wherein the inductance has a resonant half sine wave current, one capacitor discharges, and the other capacitor charges.Turn off switching losses are made negligible by selecting capacitors such that the fall time of the corresponding switching device is much faster than the time to charge the capacitor to a significant voltage.

Abstract: Disclosed are circuits for indirectly sensing and controlling the output current of switching type DC to DC converters utilizing capacitance which follows the output voltage by being responsive to switching current during the conduction period and being controllably discharged as a function of output voltage during the non-conduction period.