Hysteresis comparator circuit
First Claim
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1. A hysteresis comparator circuit comprising:
- a comparator that outputs a H-level voltage when a voltage applied to its non-inverting input terminal is equal to or larger than a voltage applied to its inverting input terminal, and outputs a L-level voltage when the above condition is not satisfied;
first and second resistors connected in series between a potential reference line and a first power line for supplying a first constant voltage being set based on an electric potential of the potential reference line in this order, with the first resistor connected to the first power line;
a third resistor connected between an interconnection point of the first and second resistors and the non-inverting input terminal of the comparator;
a first constant current source circuit for supplying a predetermined constant current to the interconnection point only while the output voltage of the comparator is the L-level; and
a second constant current source circuit for absorbing a constant current equal to the constant current supplied by the first constant current source circuit from the non-inverting input terminal of the comparator only while the output voltage of the comparator is the L-level,wherein an input voltage that is set based on the electric potential of the potential reference line is applied to the inverting input terminal of the comparator.
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Abstract
An input voltage is applied to an inverting input terminal of a comparator having no hysteresis. A first constant voltage is divided by resistors to create a reference voltage. The reference voltage is applied to a non-inverting input terminal of the comparator through a resistor. Only while an output voltage of the comparator is a low level, a predetermined constant current is supplied to a supply point of the reference voltage and a constant current of the same magnitude is absorbed from the non-inverting input terminal of the comparator.
11 Citations
12 Claims
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1. A hysteresis comparator circuit comprising:
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a comparator that outputs a H-level voltage when a voltage applied to its non-inverting input terminal is equal to or larger than a voltage applied to its inverting input terminal, and outputs a L-level voltage when the above condition is not satisfied; first and second resistors connected in series between a potential reference line and a first power line for supplying a first constant voltage being set based on an electric potential of the potential reference line in this order, with the first resistor connected to the first power line; a third resistor connected between an interconnection point of the first and second resistors and the non-inverting input terminal of the comparator; a first constant current source circuit for supplying a predetermined constant current to the interconnection point only while the output voltage of the comparator is the L-level; and a second constant current source circuit for absorbing a constant current equal to the constant current supplied by the first constant current source circuit from the non-inverting input terminal of the comparator only while the output voltage of the comparator is the L-level, wherein an input voltage that is set based on the electric potential of the potential reference line is applied to the inverting input terminal of the comparator. - View Dependent Claims (3, 5, 7)
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2. A hysteresis comparator circuit comprising:
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a comparator that outputs a H-level voltage when a voltage applied to its non-inverting input terminal is equal to or larger than a voltage applied to its inverting input terminal, and outputs a L-level voltage when the above condition is not satisfied; first and second resistors connected in series between a potential reference line and a first power line for supplying a first constant voltage being set based on an electric potential of the potential reference line in this order, with the first resistor connected to the first power line; a third resistor connected between an interconnection point of the first and second resistors and the inverting input terminal of the comparator; a first constant current source circuit for supplying a predetermined constant current to the inverting input terminal only while the output voltage of the comparator is the L-level; and a second constant current source circuit for absorbing a constant current equal to the constant current supplied by the first constant current source circuit from the connection point between the first resistor and the second resistor only while the output voltage of the comparator is the L-level, wherein an input voltage that is set based on the electric potential of the potential reference line is applied to the non-inverting input terminal of the comparator. - View Dependent Claims (4, 6, 8)
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9. A hysteresis comparator circuit comprising:
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a comparator that outputs a H-level voltage when a voltage applied to its non-inverting input terminal is equal to or more than a voltage applied to its inverting input terminal, and outputs a L-level voltage when the above condition is not satisfied; first and second resistors connected in series between a potential reference line and a first power line for supplying a first constant voltage being set based on an electric potential of the potential reference line, with the first resistor connected to the first power line; a third resistor connected between an interconnection point of the first and second resistors and the non-inverting input terminal of the comparator; a first constant current source circuit for supplying a predetermined constant current to the non-inverting input terminal only while the output voltage of the comparator is the H-level; and a second constant current source circuit for absorbing a constant current equal to the constant current supplied by the first constant current source circuit from the interconnection point only while the output voltage of the comparator is the H-level, wherein an input voltage that is set based on the electric potential of the potential reference line is applied to the inverting input terminal of the comparator. - View Dependent Claims (11)
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10. A hysteresis comparator circuit comprising:
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a comparator that outputs a H-level voltage when a voltage applied to its non-inverting input terminal is equal to or more than a voltage applied to its inverting input terminal, and outputs a L-level voltage when the above condition is not satisfied; first and second resistors connected in series between a potential reference line and a first power line for supplying a first constant voltage being set based on an electric potential of the potential reference line, with the first resistor connected to the first power line; a third resistor connected between an interconnection point of the first and second resistors and the inverting input terminal of the comparator; a first constant current source circuit for supplying a predetermined constant current to the connection point of the first resistor and the second resistor only while the output voltage of the comparator is the H-level; and a second constant current source circuit for absorbing a constant current equal to the constant current supplied by the first constant current source circuit from the inverting input terminal only while the output voltage of the comparator is the H-level, wherein an input voltage that is set based on the electric potential of the potential reference line is applied to the non-inverting input terminal of the comparator. - View Dependent Claims (12)
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Specification