Operational amplifier
AssigneeFujitsu Limited
InventorsKatsuyuki Yasukouchi, Ayuko Watabe
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Abstract
An operational amplifier that decreases idling current, widens a voltage output range, and increases load driving capacity. The operational amplifier includes a first output transistor connected to a high potential power supply. A second output transistor is connected between the first output transistor and a low potential power supply. The first and second output transistors generate an output signal at a node between the first output transistor and the second output transistor. An idling current control circuit controls the collector current of the first output transistor in accordance with the base voltage of the second output transistor to control the idling current of the first and second output transistors.
Claims6
An operational amplifier, comprising:
- a first output transistor connected to a high potential power supply;
- a second output transistor connected between the first output transistor and a low potential power supply, wherein the first and second output transistors generate an output signal at a node between the first output transistor and the second output transistor;
- and
- an idling current control circuit connected to the first and second output transistors for controlling a collector current of the first output transistor in accordance with a base voltage of the second output transistor to control an idling current of the first and second output transistors and controlling a base current of the first output transistor in accordance with the difference between the base voltage of the second output transistor and a predetermined reference voltage.
Dependencies are inferred from the claim text.