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US 2004/0061556 A1Published application
Operational amplifier with self control circuit for realizing high slew rate throughout full operating range
AssigneeNEC Electronics Corporation
InventorMakoto Miura
Life of this patent
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Abstract
An operational amplifier comprises: differential input stages to which differential signals can be inputted with full operating range; current source circuits coupled to determine current values of the differential input stages, phase inverter circuits which are provided between transistors of an output stage circuit and the current source circuits; a driver stage circuit and the output stage circuit. The phase inverter circuits control currents of the current source circuits depending on the output signal potential level. By using this structure, it becomes possible to realize a high slew rate throughout the full operating range.
Claims16
An operational amplifier comprising:
- a first differential transistor pair which is disposed between a first power supply conductor and a second power supply conductor, and which receives differential input signals at a first differential input terminal and a second differential input terminal thereof;
- a second differential transistor pair which is disposed between the first power supply conductor and the second power supply conductor, and which receives the differential input signals at a third differential input terminal and a fourth differential input terminal thereof;
- a first current source circuit coupled between the first differential transistor pair and the second power supply conductor;
- a second current source circuit coupled between the second differential transistor pair and the first power supply conductor;
- an output terminal for outputting an output signal;
- a first transistor for sourcing a drive output current via the output terminal;
- a second transistor for sinking a drive output current via the output terminal;
- an output driver stage circuit for controlling the drive output current corresponding to a signal output potential level of the output signal;
- a first phase inverter circuit which responds to a drive output potential level of the output driver stage circuit and which controls a circuit current of the first differential transistor pair in response to the rise or fall of the signal output potential level;
- and
- a second phase inverter circuit which responds to the drive output potential level of the output driver stage circuit and which controls a circuit current of the second differential transistor pair in response to the rise or fall of the signal output potential level.
8 more elements
An operational amplifier comprising:
- a first input terminal and a second input terminal;
- a first differential transistor pair of a first conductivity type and a second differential transistor pair of a second conductivity type which is different from the first conductivity type, each of the second electrodes, i.e., control electrodes, of transistors of the first and second differential transistor pairs being coupled with the first input terminal or the second input terminal;
- a first current mirror circuit which is coupled with one output of the first differential transistor pair, with one output of the second differential transistor pair, and with a first power supply conductor;
- a second current mirror circuit which is coupled with the other output of the first differential transistor pair, with the other output of the second differential transistor pair, and with the first power supply conductor;
- a load circuit (MM9, MM10) which is coupled between the second differential transistor pair and a second power supply conductor;
- an output driver stage circuit which is coupled with the coupling node between the first current mirror circuit and the load circuit, and which has two drive output terminals for controlling first and second output transistors;
- the first transistor whose second electrode, i.e., control electrode, is coupled with one of the two drive output terminals of the output drive circuit, whose first and third electrodes are coupled with the first power supply conductor and an output terminal of the operational amplifier, respectively;
- the second transistor whose second electrode, i.e., control electrode is coupled with the other of the two drive output terminals of the output drive circuit, whose first and third electrodes are coupled with the second power supply conductor and the output terminal of the operational amplifier, respectively;
- first and second current source circuits which are coupled with the first and second differential transistor pairs, respectively, and which are controlled by the output drive signals of the output driver stage circuit;
- a first phase inverter circuit which responds to a drive output potential level of the output driver stage circuit and which controls a circuit current of the first differential transistor pair in response to the rise or fall of the signal output potential level;
- and
- a second phase inverter circuit which responds to the drive output potential level of the output driver stage circuit and which controls a circuit current of the second differential transistor pair in response to the fall or rise of the signal output potential level.
9 more elements
Dependencies are inferred from the claim text.