Abstract: A variable current limiter, a power supply and a method of operating a non-isolated voltage converter are disclosed herein. In one embodiment, the variable current limiter includes: (1) a converter controller configured to regulate an output voltage of a non-isolated voltage converter and limit an output current thereof and (2) a limit provider configured to provide a variable output current limit that inversely varies with the output voltage, the converter controller configured to employ the variable output current limit to limit the output current.

Abstract: A variable current limiter, a power supply and a method of operating a non-isolated voltage converter are disclosed herein. In one embodiment, the variable current limiter includes: (1) a converter controller configured to regulate an output voltage of a non-isolated voltage converter and limit an output current thereof and (2) a limit provider configured to provide a variable output current limit that inversely varies with the output voltage, the converter controller configured to employ the variable output current limit to limit the output current.

Abstract: An impedance network for passive shoot-through protection of active switches in clamp-mode topologies. In one exemplary embodiment a switch-mode converter, includes: a primary switch; an auxiliary switch coupled in series with a capacitor; and an impedance network, coupled to the primary switch and the auxiliary switch; configured to limit current during simultaneous conduction of the primary and auxiliary switches. The impedance network includes a resistor coupled in series to a diode and both in parallel with an inductor. The impedance network permits the design of a clamp-mode converter without the need for a delay between switch turn-off and turn-on of primary and auxiliary switches.

Abstract: For use with a power plant having a rectifier and a backup battery coupled to a variable load, a system for, and method of, assessing a capacity of the backup battery. In one embodiment, the system includes: (1) a controller, coupled to the rectifier, that controls an output current of the rectifier to maintain a discharge current of the backup battery at a substantially constant level and (2) a voltage sensor, coupled to the backup battery, that measures a voltage of the backup battery.

Abstract: For use with a reserve battery couplable to a charging circuit capable of providing a charging current to the reserve battery, a mode selection circuit and a method of operation thereof. The mode selection circuit includes, in one embodiment, (1) a signal generator that generates a signal based on a temperature of the reserve battery and (2) a mode-changing circuit, coupled to the signal generator, that accepts the signal and selects an alternative one of: (a) a non-charge mode in which the charging current is substantially interrupted when the temperature is greater than a reference temperature and (b) a charge mode in which the charging current is provided to the reserve battery when the temperature is less than the reference temperature.

Abstract: A battery recharging circuit for a valve regulated lead-acid battery having a plurality of cells, each cell including a positive electrode, a negative electrode, a DC voltage source for generating a voltage applied to the positive and negative battery electrodes, and a reference electrode includes a regenerating voltage source for selectively applying a regenerating voltage between the reference electrode and one of the battery electrodes for regenerating the reference electrode, and a reference voltage source for generating a reference voltage. The circuit further includes circuitry for measuring the voltage level between the reference electrode and a battery electrode after removal of the regenerating voltage from the reference electrode. Circuitry compares the measured voltage level to the reference voltage to generate an error correction signal.

Abstract: For use with a switched-mode power converter having a modulator that develops a drive signal for a power switch, a compensation circuit, a method of compensating for a change in an output characteristic of the converter and a converter employing the circuit or the method. In one embodiment the compensation circuit includes (1) a sensor that senses the output characteristic and (2) a filter, coupled to the sensor, that develops an intermediate signal representing a change in the output characteristic. The modulator adjusts a switching period of the drive signal as a function of the intermediate signal thereby to decrease a reaction delay of the converter.

Abstract: For use with a reserve battery couplable to a charging circuit capable of providing a charging current to the reserve battery, a mode selection circuit and a method of operation thereof. The mode selection circuit includes, in one embodiment, (1) a signal generator that generates a signal based on a temperature of the reserve battery and (2) a mode-changing circuit, coupled to the signal generator, that accepts the signal and selects an alternative one of: (a) a non-charge mode in which the charging current is substantially interrupted when the temperature is greater than a reference temperature and (b) a charge mode in which the charging current is provided to the reserve battery when the temperature is less than the reference temperature.

Abstract: A multiple output dc to dc converter is described that improves efficiency for auxiliary outputs using a secondary side switch. The converter uses a switching circuit to place an alternating voltage from a dc power source across a transformer. The switching circuit is controlled by a primary PWM controller which regulates the primary output voltage by adjusting the duty cycle of the switching circuit. The switching circuit produces an alternating voltage across the center-tapped winding of the transformer, which is rectified by diodes connected to the winding to create a full-wave output. This output is used by a primary output circuit to create the primary output voltage, and is also used to create an auxiliary output voltage by using a secondary side switch and auxiliary PWM controller to regulate the auxiliary output.

Abstract: In a modular power supply having a plurality of module slots capable of receiving power supply modules therein, a system and method for controlling the power supply modules to regulate an overall output characteristic of the modular power supply, including: (1) an overall control circuit for sensing an overall output characteristic of the modular power supply and developing therefrom an overall error signal representing a deviation of the overall output characteristic from a reference characteristic and (2) a separate module control circuit for each of the power supply modules, each separate module control circuit sensing an output characteristic of an associated power supply module and developing therefrom and from the overall error signal a regulating signal for the associated power supply module, the regulating signal controlling the output characteristic of the associated power supply module to control the overall output characteristic of the modular power supply.

Abstract: A power factor correction system with an EMI input filter includes circuitry to sense the capacitor current of the filter to improve the accuracy of the power factor enhancement by providing a split current sensing resistor connected to the EMI filter or a voltage sensing capacitor. Both arrangements may be tightly coupled to the current control loop of the power factor control and compensate for the unsensed current in the EMI filter capacitors.