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US 7,786,801 B2Granted
Operational amplifier having high slew rate and stability, and operating method thereof
AssigneeSamsung Electronics Co., Ltd.
InventorHyoung Rae Kim
Life of this patent
Estimating the term…
Abstract
An operational amplifier includes a differential amplifier, an output stage, and a control unit. The differential amplifier generates a first current through a first output node and a second current through a second output node in response to a voltage difference between a first input signal input through a first input terminal and a second input signal input through a second input terminal. The output stage generates an output signal through an output node. The control unit receives a voltage of the first output node and a voltage of the second output node, as bias voltages, and controls an output current of the output stage to determine the output signal of the output stage in response to the received voltages of the first and second output nodes.
Claims16
An operational amplifier comprising:
- a differential amplifier generating a first current through a first output node and a second current through a second output node in response to a voltage difference between a first input signal input through a first input terminal and a second input signal input through a second input terminal;
- an output stage generating an output signal through an output node;
- and
- a control unit receiving a voltage of the first output node and a voltage of the second output node, as bias voltages, and controlling an output current of the output stage to determine the output signal of the output stage in response to the received voltages of the first and second output nodes,
- wherein the control unit comprises:
- a first self biased cascode current mirror connected between the first output node, a first control node, and a first power source;
- a second self biased cascode current mirror connected between the second output node, the first power source, and an intermediate node;
- a third self biased cascode current mirror connected between the intermediate node, a second power source, and a second control node;
- and
- a bias circuit connected between the first control node and the second control node and controlling each of a voltage of the first control node and a voltage of the second control node based on the voltage of the first output node and a voltage of the intermediate node.
7 more elements
An operational amplifier comprising:
- a differential amplifier generating a first current through a first output node and a second current through a second output node in response to a voltage difference between a first input signal input through a first input terminal and a second input signal input through a second input terminal;
- an output stage generating an output signal through an output node;
- and
- a control unit receiving a voltage of the first output node and a voltage of the second output node, as bias voltages, and controlling an output current of the output stage to determine the output signal of the output stage in response to the received voltages of the first and second output nodes,
- wherein the control unit comprises:
- a first self biased cascode current mirror connected between the first output node, a first control node, a first power source, and a first intermediate node;
- a second self biased cascode current mirror connected between the second output node, the first self biased cascode current mirror, and a second intermediate node;
- a third self biased cascode current mirror connected between the second intermediate node, a second power source, and a second control node;
- and
- a bias circuit connected between the first control node and the second control node and controlling each of a voltage of the first control node and a voltage of the second control node based on the voltage of the first output node and a voltage of the second intermediate node.
7 more elements
A method of operating an operational amplifier, the method comprising:
- generating first current through a first output node and second current through a second output node in response to a voltage difference between a first input signal input through a first input terminal and a second input signal input through a second input terminal, using a differential amplifier;
- receiving a voltage of the first output node and a voltage of the second output node, as bias voltages, and controlling a first control voltage and a second control voltage in response to the received voltages of the first and second output nodes, using a control unit;
- and
- controlling an output signal of an output node of an output stage in response to the first control voltage and the second control voltage,
- wherein the controlling of the first control voltage and the second control voltage comprises:
- mirroring the second current by using at least one self biased cascode current mirror;
- and
- controlling the first control voltage in response to the voltage of the first output node and the second control voltage in response to the second current that is mirrored, using the control unit.
5 more elements
A display device comprising:
- a liquid crystal panel including a plurality of data and gate lines;
- a controller to generate a plurality of control signals to control an operation of the display device;
- a source driver configured to output data signals to the data lines based on received image data and in response to at least one of the control signals;
- a gate driver configured to drive the gate lines in response to at least one of the control signals and;
- a common voltage generator configured to generate a voltage for charging and discharging a common electrode line corresponding to the source lines and comprising a pair of operational amplifiers, wherein each operational amplifier comprises:
- a differential amplifier generating a first current through a first output node and a second current through a second output node in response to a voltage difference between a first input signal input through a first input terminal and a second input signal input through a second input terminal;
- an output stage generating an output signal through an output node;
- and
- a control unit receiving a voltage of the first output node and a voltage of the second output node, as bias voltages, and controlling output current of the output stage to determine the output signal of the output stage in response to the received voltages of the first and second output nodes.
6 more elements
Dependencies are inferred from the claim text.