Dual input voltage power source for selectively switching between voltage doubler rectification and full-wave rectification functions
AssigneeFuji Electrochemical Co., Ltd.
InventorsFumiaki Nakao, Noboru Kato
Life of this patent
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Abstract
In an automatic voltage switching power source having a full-wave rectifier circuit and a voltage doubler circuit, a controller comprises a plurality of voltage level detectors which are associated with an input ac voltage and detect different voltages, and a switching signal generator which generates a delayed signal for switching between the full-wave rectifier and voltage doubler circuits based on the logical product of the outputs of the voltage level detectors, thereby preventing the electric circuit of the power source and the electric device to be supplied with the power from being damaged by excessively high voltages.
Claims8
A dual input voltage power source for selectively switching between voltage doubler rectification and full-wave rectification functions comprising a rectifying circuit having both of a voltage doubler rectification means and a full-wave rectification means, a switch means for switching between the voltage doubler rectification means and the full-wave rectification means of said rectifying circuit, and a control means for controlling said switch means in accordance with a value of an input ac voltage to said rectifying circuit, wherein said control means comprises:
- a plurality of voltage level detector means for detecting different voltages of said input ac voltage and including at least first and second voltage level detector means, each said voltage level detector means having a comparing and pulse generating means for comparing the voltage provided by rectifying said input ac voltage with a reference voltage and for generating an output pulse when the instantaneous value of said voltage is higher than said reference voltage, and each of said comparing and pulse generating means of said first and second voltage level detector means including first and second comparators, each of said first and second comparators having hysteresis for providing effective output pulses each having a predetermined width;
- and
- a switching signal generator means for generating a delayed signal for switching said switch means based on the simultaneous occurrence of specific states at the outputs of said plurality of voltage level detector means.
Dependencies are inferred from the claim text.