Comparator circuit
First Claim
1. A comparator circuit, comprising:
- a first operational amplifier having a differential input;
first and second voltage dividers coupled to a variable and a constant voltage source, respectively, having outputs coupled to the differential input to supply a differential input voltage thereto, the first operational amplifier having an output coupled to the differential input and providing an output voltage stepwise varying between first and second voltage levels at an inversion of the differential input voltage, and one of the first and second voltage dividers having a stepwise variable voltage dividing factor controlled by the output voltage of the first operational amplifier to increase the magnitude of the differential input voltage by a step value upon the inversion of the differential input voltage.
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Accused Products
Abstract
A comparator circuit and voltage level detector comprising such comparator circuit including a first operational amplifier having a differential input, first and second voltage dividers being coupled to, respectively, a variable and a constant voltage source, outputs thereof being coupled to the differential input for supplying a differential input voltage thereto. The first operational amplifier having an output being coupled to its differential input and providing an output voltage stepwise varying between first and second voltage levels at an inversion of the differential input voltage. In order to lower power consumption and increase the accuracy of level detection, one of the first and second voltage dividers is being provided with a stepwise variable voltage dividing factor, which is controlled by the output voltage of the first operational amplifier to increase the magnitude of the differential input voltage by a step value upon such inversion of the differential input voltage.
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Citations
19 Claims
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1. A comparator circuit, comprising:
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a first operational amplifier having a differential input;
first and second voltage dividers coupled to a variable and a constant voltage source, respectively, having outputs coupled to the differential input to supply a differential input voltage thereto, the first operational amplifier having an output coupled to the differential input and providing an output voltage stepwise varying between first and second voltage levels at an inversion of the differential input voltage, and one of the first and second voltage dividers having a stepwise variable voltage dividing factor controlled by the output voltage of the first operational amplifier to increase the magnitude of the differential input voltage by a step value upon the inversion of the differential input voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 18, 19)
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15. A voltage level detector, comprising:
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a comparator comprising;
a first operational amplifier having a differential input;
first and second voltage dividers coupled to a variable and a constant voltage source, respectively, having outputs coupled to the differential input to supply a differential input voltage thereto, the first operational amplifier having an output coupled to the differential input and providing an output voltage stepwise varying between first and second voltage levels at an inversion of the differential input voltage, and one of the first and second voltage dividers having a stepwise variable voltage dividing factor controlled by the output voltage of the first operational amplifier to increase the magnitude of the differential input voltage by a step value upon the inversion of the differential input voltage, wherein the constant voltage source is temperature stabilized.
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Specification