Large swing input/output analog buffer
First Claim
1. An analog buffer, comprising:
- an input stage comprising a plurality of input MOS transistors for receiving an electrical input signal, a first node where a first electrical control signal is generated, and a second node where a second electrical control signal is generated; and
a push-pull output stage comprising an output node where an electrical output signal is generated and a plurality of groups of MOS transistors including a first group of MOS transistors, a second group of MOS transistors, a third group of MOS transistors and a fourth group of MOS transistors, wherein said first group of MOS transistors is responsive to the first electrical control signal to increase the output signal in response to an increase in the input signal, wherein said second group of MOS transistors is responsive to the second electrical control signal to decrease the output signal in response to a decrease in the input signal, wherein said third group of MOS transistors assists in increasing the output signal in response to an increase in the input signal at a relatively high end of the input voltage signal range and wherein said fourth group of MOS transistors assists in decreasing the output signal in response to a decrease in the input signal at a relatively low end of the input voltage signal range.
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Accused Products
Abstract
An analog buffer comprising a bias circuit, an n input stage, a p-input stage, and a push-pull output stage which generates an output voltage signal and which is configured and operated such that the output voltage signal is able to quickly and accurately respond to changes in the input voltage signal. The push-pull output stage comprises a pair of output transistors which having a common drain connection forming an output node where the output voltage signal is generated. The push-pull output stage further comprises a first group of PMOS transistors, one of which is responsive to a first control signal generated in the n-input stage to increase the output signal in response to an increase in the input signal, and a second group of NMOS transistors, one of which is responsive to a second control signal generated in the p-input stage to decrease the output signal in response to a decrease in the input signal. A third group of MOS transistors assists in increasing the output signal in response to an increase in the input signal at a relatively high end of the input signal range, and a fourth group of MOS transistors assists in decreasing the output signal in response to a decrease in the input signal at a relatively low end of the input signal range.
48 Citations
25 Claims
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1. An analog buffer, comprising:
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an input stage comprising a plurality of input MOS transistors for receiving an electrical input signal, a first node where a first electrical control signal is generated, and a second node where a second electrical control signal is generated; and a push-pull output stage comprising an output node where an electrical output signal is generated and a plurality of groups of MOS transistors including a first group of MOS transistors, a second group of MOS transistors, a third group of MOS transistors and a fourth group of MOS transistors, wherein said first group of MOS transistors is responsive to the first electrical control signal to increase the output signal in response to an increase in the input signal, wherein said second group of MOS transistors is responsive to the second electrical control signal to decrease the output signal in response to a decrease in the input signal, wherein said third group of MOS transistors assists in increasing the output signal in response to an increase in the input signal at a relatively high end of the input voltage signal range and wherein said fourth group of MOS transistors assists in decreasing the output signal in response to a decrease in the input signal at a relatively low end of the input voltage signal range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An analog buffer, comprising:
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an n-input stage comprising a pair of input NMOS transistors for receiving an electrical input signal, said pair of input NMOS transistors being coupled together to form a node where a first electrical control signal is generated; a p-input stage comprising a pair of input PMOS transistors for receiving the electrical input signal, said pair of input PMOS transistors being coupled together to form a node where a second electrical control signal is generated; and a push-pull output stage comprising a pair of output transistors comprising; a pair of output transistors including a PMOS transistor biased by a third electrical control signal and an NMIOS transistor biased by a fourth electrical control signal, said pair of output transistors having a common drain connection forming an output node where an electrical output signal is generated, a first group of PMOS transistors, one of which is responsive to the first control signal to increase the output signal in response to an increase in the input signal, a second group of NMOS transistors, one of which is responsive to the second control signal to decrease the output signal in response to a decrease in the input signal, a third group of MOS transistors comprising a PMOS and an NMOS transistor to assist in increasing the output signal in response to an increase in the input signal at a relatively high end of the input voltage signal range, and a fourth group of MOS transistors comprising a PMOS and an NMOS transistor to assist in decreasing the output signal in response to a decrease in the input signal at a relatively low end of the input voltage signal range.
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11. An analog buffer, comprising:
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means for receiving an electrical input signal and for generating first and second electrical control signals; and means for generating an electrical output signal, said generating means comprising a plurality of groups of MOS transistors including a first group of MOS transistors, a second group of MOS transistors, a third group of MOS transistors and a fourth group of MOS transistors, wherein said first group of MOS transistors is responsive to the first electrical control signal to increase the output signal in response to an increase in the input signal, wherein said second group of MOS transistors is responsive to the second electrical control signal to decrease the output signal in response to a decrease in the input signal, wherein said third group of MOS transistors assists in increasing the output signal in response to an increase in the input signal and wherein said fourth group of MOS transistors assists in decreasing the output signal in response to a decrease in the input signal. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. An apparatus, comprising:
an analog buffer, comprising; an input stage comprising a plurality of input MOS transistors for receiving an electrical input signal, a first node where a first electrical control signal is generated, and a second node where a second electrical control signal is generated; a push-pull output stage comprising an output node where an electrical output signal is generated and a plurality of groups of MOS transistors including a first group of MOS transistors and a second group of MOS transistors, wherein said first group of MOS transistors is responsive to the first electrical control signal to increase the output signal in response to an increase in the input signal and wherein said second group of MOS transistors is responsive to the second electrical control signal to decrease the output signal in response to a decrease in the input signal; a sampling circuit; an amplifier in electrical communication with the sampling circuit; and a voltage-current reference circuit which includes the analog buffer for providing reference voltage and current signals to the sampling circuit and the amplifier. - View Dependent Claims (20, 21, 22, 23, 24)
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25. A method of making an analog buffer, comprising:
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providing an input stage comprising a plurality of input MOS transistors connected to receive an electrical input signal, a first node where a first electrical control signal is generated, and a second node where a second electrical control signal is generated; and providing a push-pull output stage comprising a output node where an electrical output signal is generated and a plurality of groups of MOS transistors including a first group of MOS transistors, a second group of MOS transistors, a third group of MOS transistors and a fourth group of MOS transistors, wherein said first group of MOS transistors is responsive to the first electrical control signal to increase the output signal in response to an increase in the input signal, wherein said second group of MOS transistors is responsive to the second electrical control signal to decrease the output signal in response to a decrease in the input signal, wherein said third group of MOS transistors assists in increasing the output signal in response to an increase in the input signal at a relatively high end of the input voltage signal range and wherein said fourth group of MOS transistors assists in decreasing the output signal in response to a decrease in the input signal at a relatively low end of the input voltage signal range.
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Specification