Patent ID: 6504270
Filing Date: 2003-01-07
Classification: H02J,H02M

Abstract:
An uninterruptible switching regulator,wherein an AC-side RCC type switching circuit equipped with a switching element, which rectifies and converts into DC an AC voltage from a commercial AC power supply serving as the input source and then operates using the smoothed DC voltage as its input, is connected to the primary winding of a high-frequency transformer, there is provided an input voltage detection circuit that detects when the input voltage from the commercial AC power supply to the AC-side RCC type switching circuit drops below a set voltage, a secondary drive circuit for driving a load such as a computer board is connected to the secondary winding of the high-frequency transformer, a DC-side RCC type switching circuit equipped with a switching element, which is completely electrically insulated from the AC-side RCC type switching circuit and the secondary drive circuit and operates using a battery, an external DC power supply, or the like as its input source, is connected to the tertiary winding of the high-frequency transformer, there is provided high-speed switching means for switching at high speed the operation of the AC-side RCC type switching circuit and the DC-side RCC type switching circuit on the basis of the detection information from the input voltage detection circuit, when the input voltage detection circuit detects that the input voltage from the commercial AC power supply is at or above the set voltage, the operation of the DC-side RCC type switching circuit is halted and power is supplied to the secondary drive circuit by preferentially operating the AC-side RCC type switching circuit with an output command from the input voltage detection circuit, and when the input voltage detection circuit detects that the input voltage from the commercial AC power supply has dropped below the set voltage, power is supplied to the secondary drive circuit by operating the DC-side RCC type switching circuit and halting the operation ofthe AC-side RCC type switching circuit with a reverse output command from the input voltage detection circuit, and further, wherein there is provided a comparative amplifying element with an internal reference voltage for keeping the DC output to the secondary drive circuit at a constant voltage, the photo-diode sides of two photo-couplers are connected to the output terminal of this comparative amplifying element, either serially or in parallel via a balance resistor, the photo-transistors of the two photo-couplers are disposed one in the AC-side RCC type switching circuit and the other in the DC-side RCC type switching circuit, the collector terminals of the two photo-transistors are connected to the feedback input terminals of a PWM control IC used to control the switching circuits, the emitter terminals of the two photo-transistors are connected to the ground terminal ofthe PWM control IC, there are provided two transistors whose collector terminals are connected to the collector terminals of the two photo-transistors and whose emitter terminals are connected to the emitter terminals thereof, the base terminals ofthe two transistors and the input voltage detection circuit are connected such that the output commands from the input voltage detection circuit can be transmitted to the two base terminals in a mutually inverted state, and an RCC partial resonance type control IC, or an IC having substantially the same finction as said IC, or a control circuit having substantially the same finction as said IC, is used as the PWM control IC.