Voltage level judging device
First Claim
1. In a voltage level judging device connected to a power source outputting a source voltage and to a load for determining whether said source voltage from said power source is below a standard level but above a specified threshold voltage or below said threshold voltage, the improvement wherein said voltage level judging device comprisesa voltage divider means for dividing said source voltage and thereby outputting a divided voltage which is a specified fraction of said source voltage,a single voltage level detection means for comparing an applied voltage with said threshold voltage and outputting an OK signal if said applied voltage is above said threshold voltage and a not-OK signal if said applied voltage is not above said threshold voltage,switching means for selectably causing said source voltage or said divided voltage to be applied to said voltage level detection means, andcontrol means for controlling operation of said voltage level judging device, said control means continuing to operate said switching means so as to cause said divided voltage to be applied to said voltage level detection means as long as said voltage level detection means outputs said OK signal, said control means operating said switching means to cause said source voltage to be applied to said voltage level detection means if said voltage level detection means outputs said not-OK signal while said divided voltage is applied thereto, said control means outputting a first warning signal if said voltage level detection means outputs said OK signal while said source voltage is applied thereto, and said control means outputting a second warning signal different from said first warning signal if said voltage level detection means outputs said not-OK signal while said source voltage is applied thereto.
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Abstract
A device for determining whether a source voltage from a power source to be applied to a load such as an electrical apparatus is below a standard level but above a specified level or below this specified level includes a voltage divider circuit for dividing the source voltage, a single voltage level detection circuit for comparing an inputted voltage, a transistor switch with which the source voltage or the output voltage from the voltage divider circuit is selectably inputted to the voltage level detection circuit, and a central processing unit for controlling the operation of the transistor switch according to the result of detection by the voltage level detection circuit.
36 Citations
7 Claims
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1. In a voltage level judging device connected to a power source outputting a source voltage and to a load for determining whether said source voltage from said power source is below a standard level but above a specified threshold voltage or below said threshold voltage, the improvement wherein said voltage level judging device comprises
a voltage divider means for dividing said source voltage and thereby outputting a divided voltage which is a specified fraction of said source voltage, a single voltage level detection means for comparing an applied voltage with said threshold voltage and outputting an OK signal if said applied voltage is above said threshold voltage and a not-OK signal if said applied voltage is not above said threshold voltage, switching means for selectably causing said source voltage or said divided voltage to be applied to said voltage level detection means, and control means for controlling operation of said voltage level judging device, said control means continuing to operate said switching means so as to cause said divided voltage to be applied to said voltage level detection means as long as said voltage level detection means outputs said OK signal, said control means operating said switching means to cause said source voltage to be applied to said voltage level detection means if said voltage level detection means outputs said not-OK signal while said divided voltage is applied thereto, said control means outputting a first warning signal if said voltage level detection means outputs said OK signal while said source voltage is applied thereto, and said control means outputting a second warning signal different from said first warning signal if said voltage level detection means outputs said not-OK signal while said source voltage is applied thereto.
Specification