Output hold-up circuit for a step-up voltage regulator
AssigneeUnisys Corporation
InventorsBertrand Bosse, Thomas Gati
Life of this patent
Estimating the term…
Abstract
An arrangement for enhancing the available energy storage capability of a hold-up energy storage element for use with the step-up or boost regulator stage of a power supply enables use of smaller hold-up storage elements, such as capacitors. The circuit stores energy at the boost regulator output and returns the energy either to the regulator input in the event of a transient line failure, or to the regulator output during a load transient. The invention provides improved transient fault tolerance by increasing the hold-up time of the storage element.
Claims15
In a voltage regulator having an input for receiving a DC input voltage and an output for furnishing a DC output voltage to a load, improved means for sustaining the output voltage within a predetermined tolerance during fault conditions comprising:
- energy storage means;
- and
- coupling means coupled to the energy storing means, the input and output of the regulator and the load, the coupling means operative, during fault-free operation of the regulator and load, to couple the energy storage means for charging to a predetermined voltage level, the coupling means further operative, upon an occurrence of a fault condition at the regulator input, to couple the energy storage means across the regulator input.
Apparatus for storing energy at an output of a step-up voltage regulator supplying a load with an output voltage greater than the regulator input voltage, the apparatus comprising:
- energy storage means coupled between first and second regulator output terminals;
- a first electronic switch, coupled between the energy storage means and a regulator input terminal, operative to couple the energy storage means to the regulator input terminal upon occurrence of a regulator input fault condition;
- a second electronic switch, coupled between the energy storage means and the load, operative to couple the energy storage means to the load upon the occurrence of a load fault condition;
- and
- charging path means coupling the energy storage means to the regulator output for charging during fault-free regulator and load operation.
A hold-up circuit for a power supply having a step-up voltage regulator with a regulator input coupled for receipt of rectified line voltage and a regulator output coupled to a load, the hold-up circuit comprising:
- a hold-up capacitor and a charging resistor serially coupled across the regulator output;
- a controlled rectifier and a zener reference diode, the rectifier having an anode electrode coupled to a junction of the hold-up capacitor and charging resistor, a cathode electrode coupled to the regulator input, and a gate electrode coupled to an anode electrode of the zener diode, with the anode electrode of the rectifier additionally coupled to a cathode electrode of the zener diode;
- and
- a diode having an anode electrode coupled to the junction of the capacitor and resistor and a cathode electrode coupled to the regulator output.
Dependencies are inferred from the claim text.