Patent ID: 8044686

Claim:
A comparator circuit comprising: a comparator comprising first and second input terminals, and configured to compare a signal inputted to the first input terminal with a signal inputted to the second input terminal; a first resistor comprising a first end to which a signal from outside is inputted, and a second end electrically connected to the first input terminal; a second resistor comprising a third end to which the signal from outside is inputted, and a fourth end electrically connected to the second input terminal; first and second voltage sources electrically connected to each other in series, the first voltage source comprising fifth and sixth ends, the second voltage source comprising seventh and eighth ends, and the sixth and seventh ends being connected to a first shared connection point to which the signal from outside is inputted; a first operational amplifier comprising third and fourth input terminals and a first output terminal, the third input terminal being connected to the fifth end; a first diode comprising a cathode connected to the first output terminal, and an anode connected to the fourth input terminal; a second operational amplifier comprising fifth and sixth input terminals and a second output terminal, the fifth input terminal being connected to the eighth end; a second diode comprising an anode connected to the second output terminal, and a cathode connected to the sixth input terminal, the anode of the first diode and the cathode of the second diode being connected to a second shared connection point, and the second shared connection point being connected to a node between the fourth end of the second resistor and the second input terminal of the comparator; and a capacitor comprising a ninth end connected to a ground terminal, and a tenth end connected to a node between the second shared connection point and the second input terminal of the comparator, wherein the first and second voltage sources, the first and second operational amplifiers, and the first and second diodes collectively form a charge/discharge circuit, and wherein the second resistor is connected in parallel with respect to the charge/discharge circuit.