Abstract: The invention relates to a switch-mode power converter including a bias circuit. A power converter power transformer includes a magnetic core. The switch-mode power converter power transformer also includes an initial bias primary winding and an initial bias secondary winding, both wound on the magnetic core, wherein the initial bias secondary winding shares at least one magnetic path in common with the initial bias primary winding. A driver is configured to drive the initial bias primary winding with high frequency pulses when enabled by an enable signal. A rectifier and capacitor are configured to provide a voltage to power a control circuit during a power converter start-up. A method provides an initial bias power for a power converter output side referenced controller, powering the output side referenced controller from the initial bias windings.

Abstract: The invention relates to a switch-mode power converter including a bias circuit. A power converter power transformer includes a magnetic core. The switch-mode power converter power transformer also includes an initial bias primary winding and an initial bias secondary winding, both wound on the magnetic core, wherein the initial bias secondary winding shares at least one magnetic path in common with the initial bias primary winding. A driver is configured to drive the initial bias primary winding with high frequency pulses when enabled by an enable signal. A rectifier and capacitor are configured to provide a voltage to power a control circuit during a power converter start-up. A method provides an initial bias power for a power converter output side referenced controller, powering the output side referenced controller from the initial bias windings.

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 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: 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: 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: 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: 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, a low profile magnetic device comprises a crelenated ferrite body having first and second conductive paths winding around the body. Current applied to one of the conductive windings can adjust the threshold current level in the other conductive winding at which the inductance characteristic changes to a relatively constant inductance.

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: A feedback circuit is included in paralleled power supply modules using a modified master/slave current sharing scheme. The feedback circuit is activated in the slave modules to force the internal control signal generated by each of the controllers acting as slaves to operate in a predetermined manner. This predetermined manner can be by adjusting the local control signal such that it approximates the master control signal, either by forcing it to follow the master control signal, or by separately regulating the local control signal to approximate the master control signal, or it can be by maintaining the local control signal at a predetermined value. The feedback circuit acts to prevent sudden changes in the output voltage when the master module fails and another module becomes master by placing its control signal on the current-share bus.

Abstract: A circuit and a method for providing current sharing between parallel power supplies using a modified master/slave scheme in which any of the parallel modules can be designated the master is described. A current-share circuit is incorporated into each power supply which includes its own controller producing an internal control signal and is interconnected to the other power supply modules on a current-share bus. The current-share circuit includes a switch, which is operable to connect the power supplies internal control signal to the current-share bus when closed and disconnect the internal control signal from the current-share bus when open. The switch is controlled by master/slave logic, which determines whether the power supply is the master or a slave and controls the switch accordingly. The master is determined by closing all of the switches, thereby placing all of the power supplies' internal control signals on the bus.

Abstract: For use with a power converter having a current sensor that senses an output current of the converter and generates a proportional voltage and a controller having an overvoltage protection circuit associated therewith. The overvoltage protection circuit includes a voltage sense input coupled to an output of the converter and a first reference voltage input, an integrated protection circuit, method of providing current-limiting and short-circuit protection and power converter employing the same. In one embodiment, the integrated protection circuit includes an operation amplifier circuit, coupled between the current sensor and the controller, that generates a voltage signal and causes the controller to limit a current supplied by the converter to the output when the proportional voltage exceeds a second reference voltage.

Abstract: For use in a power converter having a power switch and a synchronous rectifier device coupled between an input and an output thereof, a transient response network, method of disabling a synchronous rectifier device and power converter employing the network and method. In one embodiment, the transient response network includes a synchronous rectifier controller, coupled to the power switch and the synchronous rectifier device, that senses a state of the power switch and disables the synchronous rectifier device when the power switch has remained in a nonconducting state for at least a specified period of time.

Abstract: A system for, and method of, voltage positioning a regulator and a regulator employing the system or the method. The regulator has an input coupled to a switching network and an output coupled to a load. In one embodiment, the voltage positioning system, includes a current sensor, coupled to the output, that senses an output current of the regulator and generates a proportional voltage. The system further includes a voltage sensor, coupled to the load, that senses a load voltage and the proportional voltage. The system still further includes a controller, coupled to the voltage sensor, that generates a signal to control the switching network as a function of the load voltage and the proportional voltage.

Abstract: A buck switching DC-to-DC regulator having a resistor and capacitor in combination across the storage inductor to measure output current and voltage. The resistor connects to the input of the inductor and the capacitor to the output of the inductor. The junction of the resistor and capacitor connects to 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: A buck switching DC-to-DC regulator having a resistor and capacitor in combination across the storage inductor to measure output current and voltage. The resistor connects to the input of the inductor and the capacitor to the output of the inductor. The junction of the resistor and capacitor connects to 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.