High-gain, bulk-driven operational amplifiers for system-on-chip applications
First Claim
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1. A rail-to-rail operational transconductance amplifier comprising:
- an input;
an output; and
an amplifier core connected to the input and the output;
wherein the amplifier core comprises a bulk-driven operational transconductance amplifier element and an auxiliary gain-boosting amplifier connected to the bulk-driven operational transconductance amplifier element to boost a gain of the bulk-driven operational transconductance amplifier element, and wherein the bulk-driven operational transconductance amplifier element and the auxiliary gain-boosting amplifier are connected to provide local feedback action between the bulk-driven operational transconductance amplifier element and the auxiliary gain-boosting amplifier to reduce variations in bias current in the bulk-driven operational transconductance amplifier element.
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Abstract
An ultra-low voltage rail-to-rail operational transconductance amplifier (OTA) is based on a standard digital 0.18 μm CMOS process. Techniques for designing a 0.8 volt fully differential OTA include bias and reference current generator circuits. To achieve rail-to-rail operation, complementary input differential pairs are used, where the bulk-driven technique is applied to reduce the threshold limitation of the MOSFET transistors. The OTA gain is increased by using auxiliary gain boosting amplifiers.
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Citations
16 Claims
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1. A rail-to-rail operational transconductance amplifier comprising:
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an input; an output; and an amplifier core connected to the input and the output; wherein the amplifier core comprises a bulk-driven operational transconductance amplifier element and an auxiliary gain-boosting amplifier connected to the bulk-driven operational transconductance amplifier element to boost a gain of the bulk-driven operational transconductance amplifier element, and wherein the bulk-driven operational transconductance amplifier element and the auxiliary gain-boosting amplifier are connected to provide local feedback action between the bulk-driven operational transconductance amplifier element and the auxiliary gain-boosting amplifier to reduce variations in bias current in the bulk-driven operational transconductance amplifier element. - View Dependent Claims (2)
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3. A rail-to-rail operational transconductance amplifier comprising:
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an input; an output; and an amplifier core connected to the input and the output; wherein the amplifier core comprises an input stage connected to the input, and wherein the input stage comprises a pair of bulk-driven PMOS transistors and a pair of bulk-driven NMOS transistors, the pair of bulk-driven PMOS transistors and the pair of bulk-driven NMOS transistors being connected to the input in parallel; and wherein the amplifier core further comprises an output branch connected to the output, and wherein the output branch comprises a pair of symmetric common gate amplifiers. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification