Abstract: A drive transformer and associated circuitry for providing power and appropriate delays to primary switches and synchronous rectifiers in switch-mode power converters. The circuitry takes advantage of the leakage inductances of the drive transformer windings as well as the input capacitance of the primary switches (MOSFETs) to provide the necessary delays. No separate circuitry is needed to provide such delays, thereby providing reliability. Exemplary embodiments further disclose means to disable or enable the primary winding from a condition sensed on the secondary side even with a control and feedback circuit located on the secondary side.

Abstract: In accordance with the invention, a low impedance surface-mount connector comprises a length of cylindrical rod having an I-shaped cross section. The device permits interconnection by pick-and-place techniques, and the interconnection has advantageous qualities of low resistance, low inductance, mechanical compliance and ease of manufacture. A first circuit device having one or more circuit components is interconnected with a second circuit device by surface mounting such connectors on the first circuit device, providing corresponding solder pads on the second circuit device, and mounting the connectors of the first circuit device onto the pads of the second.

Abstract: The invention is a test apparatus incorporating high current test pins, forced into contact with a circuit assembly under test by opposing compliant pressure pins. An advantageous test pin for low voltage, high current testing is a solid, one piece test pin. The solid test pin, when supplied with adequate contact force, provides both low resistance and low inductance. The required compliant force is applied to the test circuit, opposite and substantially in line with the solid test pin, by a compliant pressure pin. Since the test pin does not supply the compliant force, it can be designed primarily for the desired electrical parameters of the test contact. The only mechanical considerations for the conductive solid pin are the amount of desired surface contact area, the dominant mechanical parameter in setting the contact resistance, and the body dimensions, which determine the resistance and inductance of the pin itself.

Abstract: A switching regulator includes at least two power switches and two rectifier switches, power transformer having a primary and secondary windings, control circuit for generating control pulses for the power switches, an inductor for providing output current to the load and connected, and a current sensor coupled to the secondary windings and the inductor for sensing current passing through the inductor. The current sensor preferably includes a first and second resistor and a capacitor connected together, and provides a sensed voltage at its output proportional to the product of output current of the inductor and inherent DC resistance of the inductor and the secondary windings. The current sensor is coupled to the control circuit for regulation and protecting the switching regulator against overload or short circuit conditions.

Abstract: A drive transformer and associated circuitry for providing power and appropriate delays to primary switches and synchronous rectifiers in switch-mode power converters in a full-bridge topology. The invention takes advantage of the leakage inductances of the drive transformer windings as well as the input capacitance of the primary switches (MOSFETs) to provide the delays. No separate circuitry is needed to provide such delays, thereby providing reliability. Exemplary embodiments further disclose means to disable or enable the primary winding from a condition sensed on the secondary side even with a control and feedback circuit located on the secondary side. The invention further discloses means to use one drive transformer winding to control two switches completely out of phase.

Abstract: In accordance with the invention, a high quality magnetic device is produced without manual intervention by the step of providing a substrate including an aperture and conductive coil extending peripherally around the aperture and bonding together two parts of a magnetic body extending through the aperture. The two parts have substantially planar mating surfaces, and the bonding is effected by securing one of the parts to the substrate, applying adhesive to the portion of its mating surface exposed within the aperture, and pressing the mating surface of the second part into contact with the mating surface of the first part. During pressing, the mating surfaces are rotated in a reciprocating fashion to spread the adhesive into a thin, highly uniform film.

Abstract: A drive transformer and associated circuitry for providing power and appropriate delays to primary switches and synchronous rectifiers in switch-mode power converters in a full-bridge topology. The invention takes advantage of the leakage inductances of the drive transformer windings as well as the input capacitance of the primary switches (MOSFETs) to provide the delays. No separate circuitry is needed to provide such delays, thereby providing reliability. Exemplary embodiments further disclose means to disable or enable the primary winding from a condition sensed on the secondary side even with a control and feedback circuit located on the secondary side. The invention further discloses means to use one drive transformer winding to control two switches completely out of phase.

Abstract: A switching regulator includes at least two power switches and two rectifier switches, power transformer having a primary and secondary windings, control circuit for generating control pulses for the power switches, an inductor for providing output current to the load and connected, and a current sensor coupled to the secondary windings and the inductor for sensing current passing through the inductor. The current sensor preferably includes a first and second resistor and a capacitor connected together, and provides a sensed voltage at its output proportional to the product of output current of the inductor and inherent DC resistance of the inductor and the secondary windings. The current sensor is coupled to the control circuit for regulation and protecting the switching regulator against overload or short circuit conditions.

Abstract: A low impedance surface-mount connector includes a length of cylindrical rod having an I-shaped cross section. The device permits interconnection by pick-and-place techniques, and the interconnection has advantageous qualities of low resistance, low inductance, mechanical compliance and ease of manufacture. A first circuit device having one or more circuit components is interconnected with a second circuit device by surface mounting such connectors on the first circuit device, providing corresponding solder pads on the second circuit device, and mounting the connectors of the first circuit device onto the pads of the second.

Abstract: In accordance with the invention, a low impedance surface-mount connector comprises a length of cylindrical rod having an I-shaped cross section. The device permits interconnection by pick-and-place techniques, and the interconnection has advantageous qualities of low resistance, low inductance, mechanical compliance and ease of manufacture. A first circuit device having one or more circuit components is interconnected with a second circuit device by surface mounting such connectors on the first circuit device, providing corresponding solder pads on the second circuit device, and mounting the connectors of the first circuit device onto the pads of the second.

Abstract: The invention employs a coreless isolated transformer, with associated electronic circuitry, for providing an initial bias and enable signal for control and drive circuitry that is referenced to the output of a converter. The improvement is accomplished by embedding the transformer primary and secondary windings into a multi-layer PCB so that the transformer does not occupy space on the top and bottom surfaces of the PCB The initial bias voltage is used to initialize operation of the control circuit when referenced to the output side of the converter. Thus, complete regulation and drive signals are generated on the output side.

Abstract: For use in a power converter having a power switch and a synchronous rectifier device coupled between input and output thereof, a control circuit, method of disabling a synchronous rectifier device and power converter employing the control circuit and method. In one embodiment, the control circuit includes a synchronous rectifier controller, coupled to the output of the converter and the synchronous rectifier device, that senses time derivative of the output voltage and disables the synchronous rectifier when derivative is negative and greater than a predetermined magnitude.

Abstract: In accordance with the invention, a circuit module is provided with a plurality of dual capacity connector pads, each pad holding a miniature surface mount connector and/or a connection pin. The preferred I-channel surface mount connector is sufficiently small that the module can be connected by either surface mount or pin to the same region of the circuit board.

Abstract: In accordance with the invention, an I-channel surface mount connector comprising a length of cylindrical rod having a generally I-shaped cross section is improved by providing an extended mounting flange. When a first circuit device is connected to a second circuit device with the extended flange extending outward of the first device, the flange can extend beyond the periphery of the first device. This extension has the advantage that the solder bond between the flange and the second device can be easily inspected from above using visual inspection equipment.

Abstract: The invention is a test apparatus incorporating high current test pins, forced into contact with a circuit assembly under test by opposing compliant pressure pins. An advantageous test pin for low voltage, high current testing is a solid, one piece test pin. The solid test pin, when supplied with adequate contact force, provides both low resistance and low inductance. The required compliant force is applied to the test circuit, opposite and substantially in line with the solid test pin, by a compliant pressure pin. Since the test pin does not supply the compliant force, it can be designed primarily for the desired electrical parameters of the test contact. The only mechanical considerations for the conductive solid pin are the amount of desired surface contact area, the dominant mechanical parameter in setting the contact resistance, and the body dimensions, which determine the resistance and inductance of the pin itself.

Abstract: A switching regulator provides load dependent output voltage regulation by sensing voltage drop across inherent DC resistance of the output inductor and secondary windings of power transformer with a first and second resistor and a capacitor and feeding back sensed voltage into an error amplifier for controlling the switching regulator. The regulator may be paralleled for more output current by connecting the outputs together and providing a common reference voltage to all the regulators.

Abstract: In accordance with the invention, an open frame circuit assembly mounted on a planar substrate is provided with a composite low flow impedance voltage guard. The composite guard comprises an ESD protective cover portion and a clip portion to capture the cover portion and clip to the circuit board. The cover portion comprises a lower frame member extending peripherally around the assembly, an apertured top member overlying the assembly and a plurality of spaced apart struts supporting the top member from the frame. The top member and struts have rounded surfaces to preserve streamlines in air flowing over the assembly, and all openings and spacings are sufficiently small to preclude accidental human contact with the assembly. Large area portions of the cover portion are preferably made of polymer containing conductive fillers for ESD protection. The clip portion is preferably made of high elongation polymer for secure holding and clipping.

Abstract: In accordance with the invention, an electronic circuit containing one or more magnetic devices is assembled by the steps of providing a substrate including an aperture and conductive coil extending peripherally around the aperture and bonding together two parts of a magnetic body extending through the aperture. The two parts have substantially planar mating surfaces, and the bonding is effected by securing one of the parts to the substrate, applying adhesive to the portion of its mating surface exposed within the aperture, and pressing the mating surface of the second part into contact with the mating surface of the first part. During pressing, the mating surfaces are rotated in a reciprocating fashion to spread the adhesive into a thin, highly uniform film. This process permits the formation in the cure operation of a high quality bond without clamping. It thus produces a high quality magnetic device without manual intervention and can be part of a fully automated process to fabricate a circuit assembly.

Abstract: In accordance with the invention, an open frame circuit assembly mounted on a planar substrate is provided with a composite low flow impedance voltage guard. The composite guard comprises an ESD protective cover portion and a clip portion to capture the cover portion and clip to the circuit board. The cover portion comprises a lower frame member extending peripherally around the assembly, an apertured top member overlying the assembly and a plurality of spaced apart struts supporting the top member from the frame. The top member and struts have rounded surfaces to preserve streamlines in air flowing over the assembly, and all openings and spacings are sufficiently small to preclude accidental human contact with the assembly. Large area portions of the cover portion are preferably made of polymer containing conductive fillers for ESD protection. The clip portion is preferably made of high elongation polymer for secure holding and clipping.

Abstract: An I-channel surface mount connector includes a length of cylindrical rod having a generally I-shaped cross section is improved by providing an extended mounting flange. When a first circuit device is connected to a second circuit device with the extended flange extending outward of the first device, the flange can extend beyond the periphery of the first device. This extension has the advantage that the solder bond between the flange and the second device can be easily inspected from above using visual inspection equipment.