RAIL-TO-RAIL OPERATIONAL AMPLIFIER
First Claim
1. An operational amplifier, comprising:
- a first input module, comprising a first pair of input transistors and a first pair of output transistors, each of the first pair of input transistors having a first threshold voltage;
a second input module, comprising a second pair of input transistors and a second pair of output transistors, each of the second pair of input transistors having a second threshold voltage, the second threshold voltage being lower than the first threshold voltage,wherein each of the first pair of output transistors has a bulk in communication with a respective one of the first pair of input transistors, and each of the second pair of output transistors has a bulk in communication with a respective one of the second pair of input transistors, and each input module is configured to;
receive a pair of input signals differentially at a pair of input nodes in communication with the first pair of input transistors and the second pair of input transistors;
use each pair of input transistors to generate a respective pair of bulk levels as a function of the pair of input signals;
control the bulks of each pair of output transistors as a function of the respective pair of bulk levels; and
use each pair of output transistors to generate a respective pair of output signals at a pair of output nodes as a function of the respective pair of bulk levels and at least one reference level, the pair of output nodes being in communication with the first pair of output transistors and the second pair of output transistors; and
a protection module, in communication with the first input module, and configured to generate a protection control signal as a function of at least one of the pair of input signals, wherein each of the pair of output signals generated by the first pair of output transistors has an amplitude that is at least partially controlled as a function of the protection control signal.
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Accused Products
Abstract
A rail-to-rail operational amplifier has a pair of input terminals and an output terminal, and includes first and second parallel-connected differential input stages configured to generate a differential output signal OUTN, OUTP in response to a differential input signal VINN, VINP received at the pair of input terminals. Each of the first and second differential input stages in turn includes a pair of source-follower transistors and a pair of bulk-driven transistors. The pair of source-follower transistors are respectively coupled between the pair of input terminals and a bulk terminal of the pair of bulk-driven input transistors. Further, the pair of source-follower transistors in the first differential input stage have a different threshold voltage than the source-follower transistors in the second differential input stage.
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Citations
29 Claims
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1. An operational amplifier, comprising:
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a first input module, comprising a first pair of input transistors and a first pair of output transistors, each of the first pair of input transistors having a first threshold voltage; a second input module, comprising a second pair of input transistors and a second pair of output transistors, each of the second pair of input transistors having a second threshold voltage, the second threshold voltage being lower than the first threshold voltage, wherein each of the first pair of output transistors has a bulk in communication with a respective one of the first pair of input transistors, and each of the second pair of output transistors has a bulk in communication with a respective one of the second pair of input transistors, and each input module is configured to; receive a pair of input signals differentially at a pair of input nodes in communication with the first pair of input transistors and the second pair of input transistors; use each pair of input transistors to generate a respective pair of bulk levels as a function of the pair of input signals; control the bulks of each pair of output transistors as a function of the respective pair of bulk levels; and use each pair of output transistors to generate a respective pair of output signals at a pair of output nodes as a function of the respective pair of bulk levels and at least one reference level, the pair of output nodes being in communication with the first pair of output transistors and the second pair of output transistors; and a protection module, in communication with the first input module, and configured to generate a protection control signal as a function of at least one of the pair of input signals, wherein each of the pair of output signals generated by the first pair of output transistors has an amplitude that is at least partially controlled as a function of the protection control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for providing operational amplifier functionality, comprising:
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receiving a pair of input signals differentially at a first pair of input devices, the first pair of input devices being optimized to operate over a first common mode range and configured to control bulks of a first respective pair of output devices; receiving the pair of input signals differentially at a second pair of input devices, the second pair of input devices being optimized to operate over a second common mode range and configured to control bulks of a second respective pair of output devices, the second common mode range being different from the first common mode range; using each pair of input devices to generate bulk levels at the bulks of each respective pair of output devices as a function of the pair of input signals; generating a protection control signal as a function of at least one of the pair of input signals; using the first respective pair of output devices to generate a first pair of output signals as a function of the bulk levels at the bulks of the first respective pair of output devices and the protection control signal; and using the second respective pair of output devices to generate a second pair of output signals as a function of the bulk levels at the bulks of the second respective pair of output devices. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25)
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26. A system for providing operational amplifier functionality, comprising:
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a first means for differentially receiving a pair of input signals, the first means being optimized to operate over a first common mode range and configured to generate a first bulk level and a second bulk level as a function of each of the pair of input signals, respectively; a second means for differentially receiving the pair of input signals, the second means being optimized to operate over a second common mode range and configured to generate a third bulk level and a fourth bulk level as a function of each of the pair of input signals, respectively; a third means for generating a protection control signal as a function of at least one of the pair of input signals; a fourth means for generating a first output signal as a function of the first bulk level and the protection control signal; a fifth means for generating a second output signal as a function of the second bulk level and the protection control signal; a sixth means for generating a third output signal as a function of the third bulk level; and a seventh means for generating a fourth output signal as a function of the fourth bulk level. - View Dependent Claims (27, 28, 29)
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Specification