Comparator with high-voltage inputs in an extended CMOS process for higher voltage levels
First Claim
1. A method for realizing a high voltage comparator comprising:
- transforming static high supply voltage levels into static currents;
transforming a high-voltage input signal into a proportional current signal;
transforming a high-voltage reference into a proportional current reference;
combing said static currents and proportional current signal into a resulting current input signal;
combining said static currents and said proportional current reference into resulting reference current input;
feeding said resulting current input signal and said resulting reference current input into a current comparator circuit operating in a low-voltage domain;
comparing said resulting current input signal and said resulting reference current input within said current comparator circuit; and
generating a low voltage output signal representing the result of said current comparator circuit.
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Abstract
A circuit and method are given, to realize a high voltage comparator, which generates an output signal for follow-up processing in the low-voltage domain. The high-voltage comparison task is essentially replaced by a current comparison, implemented as a combination of a voltage to current transforming stage with a CMOS current comparator circuit, where only very few parts are working in the high voltage domain. Using the intrinsic advantages of that solution the circuit of the invention is manufactured with standard CMOS technology and only four discrete or integrated extended drain MOS components at low cost. This solution reduces the complexity of the circuit and in consequence also power consumption and manufacturing cost.
39 Citations
31 Claims
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1. A method for realizing a high voltage comparator comprising:
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transforming static high supply voltage levels into static currents;
transforming a high-voltage input signal into a proportional current signal;
transforming a high-voltage reference into a proportional current reference;
combing said static currents and proportional current signal into a resulting current input signal;
combining said static currents and said proportional current reference into resulting reference current input;
feeding said resulting current input signal and said resulting reference current input into a current comparator circuit operating in a low-voltage domain;
comparing said resulting current input signal and said resulting reference current input within said current comparator circuit; and
generating a low voltage output signal representing the result of said current comparator circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A circuit, capable of comparing higher voltage signals, comprising:
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means for transforming a static high voltage supply level into static currents;
means for transforming a high voltage input signal into a proportional current signal;
means for transforming a high voltage reference input into a proportional current reference;
means for combining said static current and said proportional current signal into a resulting current input signal;
means for combining said static current and said proportional reference current into a resulting reference current input;
means for feeding said resulting current input signal and said resulting reference current into a current comparison circuit;
means for comparing said resulting current input signal and said resulting reference current, designated as said current comparison circuit; and
means for generating a low voltage output signal describing the relation of said high voltage input signal and high voltage reference input representing the result of said current comparison circuit. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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Specification