US 6,018,267 AGranted

High output swing operational amplifier using low voltage devices

AssigneeInformation Storage Devices, Inc.

InventorsHieu Van Tran, Anthony Dunne

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Abstract

A power efficient high output swing operational ("HOOP") amplifier for integrated circuit analog signal processing is described. The operational amplifier includes a differential input stage and an output stage. The differential input stage is powered by a regular power supply while the output stage is powered by a voltage multiplier which results in a high voltage output swing without sinking significant power from the voltage multiplier. The high output voltage (e.g., 23 volts) is achieved using low voltage MOS devices. An output isolation technique is utilized to prevent possible latchup and contention. The operational amplifier also features a bias boot scheme to achieve a faster settling time from power up. In addition, the present invention provides realization of frequency compensation with highest possible breakdown and reduced noise coupling. A bias arrangement between input and output stages of the operational amplifier is used to further help reduce the power drawn from the voltage multiplier and decrease the settling time.

Claims32

Dependent claims

A high output voltage swing operational amplifier, comprising:

first and second power supply terminals having first and second voltages thereon, respectively, wherein the second voltage is greater than the first voltage;
a differential input stage coupled between the first power supply terminal and a common terminal;
an output stage coupled between the second power supply terminal and the common terminal, and to the differential input stage, said output stage including first and second legs of devices, said first leg of devices including
a first device having a gate coupled to the input stage, a drain, and a source coupled to the common terminal,
a second device having a gate coupled to a first terminal having a first intermediate voltage thereon, a drain coupled to an output terminal, and a source coupled to the drain of the second device, and
a third device having a gate coupled to a second terminal having a second intermediate voltage thereon, a drain coupled to the output terminal, and a source coupled to the second power supply terminal;
said second leg of devices including
a fourth device having a gate coupled to the input stage, a drain, and a source coupled to the common terminal, and
a fifth device having a gate coupled to the first terminal, a drain coupled to the second power supply terminal, and a source coupled to the drain of the fourth device.

6 more elements

A high output voltage swing CMOS operational amplifier, comprising:

first and second power supply terminals having first and second voltages thereon, respectively, wherein the second voltage is greater than the first voltage;
an input circuit coupled between the first power supply terminal and a common terminal, and including first and second input terminals;
a bias circuit coupled between the first power supply terminal and the common terminal, and to the input circuit for biasing the input circuit;
and
an output circuit coupled between the second power supply terminal and the common terminal, and to the input circuit, said output circuit including,
a first device having a gate coupled to the input circuit, a drain, and a source coupled to the common terminal,
a second device having a gate coupled to a first terminal having a first intermediate voltage thereon, a drain coupled to an output terminal, and a source coupled to the drain of the second device,
a third device having a gate coupled to a second terminal having a second intermediate voltage thereon, a drain coupled to the output terminal, and a source,
a fourth device having a gate, a drain coupled to the source of the third device, and a source coupled to the second power supply terminal;
a fifth device having a gate coupled to the input circuit, a drain, and a source coupled to the common terminal,
a sixth device having a gate coupled to the first terminal, a drain, and a source coupled to the drain of the fifth device, and
a seventh device having a gate coupled to the gate of the fourth device, a drain coupled to its gate, and a source coupled to the second power supply terminal;
wherein the second voltage is greater than a breakdown voltage of the first through seventh devices.

10 more elements

A high output voltage swing operational amplifier, comprising:

first and second power supply terminals having first and second voltages thereon, respectively, wherein the second voltage is greater than the first voltage;
an input circuit coupled between the first power supply terminal and a common terminal, and including first and second input terminals;
an output circuit coupled between the second power supply terminal and the common terminal, and to the input circuit, said output circuit includes first and second legs of devices, said first leg of devices including,
a first device having a gate coupled to the input circuit, a drain, and a source coupled to the common terminal,
a second device having a gate coupled to a first terminal having a first intermediate voltage thereon, a drain coupled to an output terminal, and a source coupled to the drain of the second device,
a third device having a gate coupled to a second terminal having a second intermediate voltage thereon, a drain coupled to the output terminal, and a source,
a fourth device having a gate, a drain coupled to the source of the third device, and a source, and
a fifth device having a gate, a drain coupled to the source of the fourth device, and a source coupled to the second power supply terminal,
said second leg of devices including,
a sixth device having a gate, a drain, and a source coupled to the common terminal,
a seventh device having a gate coupled to the first terminal, a drain, and a source coupled to the drain of the sixth device,
an eighth device having a gate coupled to the gate of the fourth device, a drain coupled to its gate, and a source, and
a ninth device having a gate coupled to the gate of the fifth device, a drain coupled to its gate and the source of the eighth device, and a source coupled to the second power supply terminal,
wherein the second voltage is greater than a breakdown voltage of the first through ninth devices;
and
a bias circuit coupled between the first power supply terminal and the common terminal, to the input circuit for biasing the input circuit, and to the gate of the sixth device for providing a fixed bias current to the second leg of devices.

13 more elements

Dependencies are inferred from the claim text.