Inductance change detection circuit
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorMasahiro Yamamoto
Life of this patent
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Abstract
An inductance change detection circuit for detecting a change in inductance with a simple circuit design, having a series circuit having a resistor and a coil of which an inductance changes according to a position of an object; a pulse power supply 1 for applying a pulse voltage to the series circuit; a first signal generator for generating a first signal when an output voltage of the resistor in the series circuit becomes a specific voltage level; a second signal generator for generating a second signal responsive to a pulse voltage of the pulse power supply; and a comparison pulse generator for generating a pulse signal having a duty ratio responsive to the coil inductance based on the first signal and second signal.
Claims40
An inductance change detection circuit, comprising:
- a series circuit comprising a resistor and a coil of which an inductance changes according to a position of an object to be detected;
- a pulse power supply for applying a pulse voltage to said series circuit;
- a first signal generating means for generating a first signal when an output voltage of the resistor in said series circuit becomes a specific voltage level;
- a second signal generating means for generating a second signal responsive to the pulse voltage of said pulse power supply;
- and
- a comparison pulse generating means for generating a pulse signal having a duty ratio responsive to the coil inductance based on the first signal supplied from said first signal generating means and the second signal supplied from said second signal generating means,
- wherein the first and second signals have a same period.
An inductance change detection circuit, comprising:
- a series circuit comprising a resistor and a coil of which an inductance changes according to a position of an object to be detected;
- a pulse power supply configured to apply a pulse voltage to said series circuit;
- a first signal generator configured to generate a first signal when an output voltage of the resistor in said series circuit becomes a specific voltage level;
- a second signal generator configured to generate a second signal responsive to the pulse voltage of said pulse power supply;
- and
- a comparison pulse generator configured to generate a pulse signal having a duty ratio responsive to the coil inductance based on the first signal supplied from said first signal generator and the second signal supplied from said second signal generator,
- wherein the first and second signals have a same period.
An inductance change detection circuit, comprising:
- a series circuit comprising a resistor and a coil of which an inductance changes according to a position of an object to be detected;
- a pulse power supply for applying a pulse voltage to said series circuit;
- a first signal generating means for generating a first signal when an output voltage of the resistor in said series circuit becomes a specific voltage level;
- a second signal generating means for generating a second signal responsive to the pulse voltage of said pulse power supply;
- and
- a comparison pulse generating means for generating a pulse signal having a duty ratio responsive to the coil inductance based on the first signal supplied from said first signal generating means and the second signal supplied from said second signal generating means,
- wherein said first signal generating means generates the first signal at a timing between a time when the output voltage of said resistor becomes a first predefined voltage level and a time when the output voltage becomes a second predefined voltage level, and
- wherein the first and second voltage levels are half the amplitude of the pulse voltage, respectively.
An inductance change detection circuit, comprising:
- a series circuit comprising a resistor and a coil of which an inductance changes according to a position of an object to be detected;
- a pulse power supply configured to apply a pulse voltage to said series circuit;
- a first signal generator configured to generate a first signal when an output voltage of the resistor in said series circuit becomes a specific voltage level;
- a second signal generator configured to generate a second signal responsive to the pulse voltage of said pulse power supply;
- and
- a comparison pulse generator configured to generate a pulse signal having a duty ratio responsive to the coil inductance based on the first signal supplied from said first signal generator and the second signal supplied from said second signal generator,
- wherein said first signal generator generates the first signal at a timing between a time when the output voltage of said resistor becomes a first predefined voltage level and a time when the output voltage becomes a second predefined voltage level, and
- wherein the first and second voltage levels are half the amplitude of the pulse voltage, respectively.
Dependencies are inferred from the claim text.