Differential amplifier
AssigneeAsahi Kasei Microdevices Corporation
InventorDaisuke Matsuoka
Life of this patent
Estimating the term…
Abstract
A differential amplifier is provided, in which generation of unnecessary harmonic distortion in the differential output signal is suppressed. A common mode feedback circuit increases or decreases operating points of an inverting output terminal and a non-inverting output terminal such that an intermediate voltage of voltages respectively provided to an inverting input terminal and a non-inverting input terminal is consistent with to a reference voltage. Variations in voltage at the inverting input terminal and the non-inverting input terminal are suppressed, variations in electrical properties of elements connected to the input terminals are suppressed. Therefore, it is possible to suppress generation of harmonic distortion in the output signals from the inverting output terminal and the non-inverting output terminal.
Claims4
A differential amplifier comprising:
- an inverting input terminal;
- a non-inverting input terminal;
- an inverting output terminal;
- a non-inverting output terminal;
- an input differential pair that determines operating points of the inverting output terminal and the non-inverting output terminal;
- a common mode detection circuit, to which a reference signal is received, which generates a signal based on a differential between the reference voltage and an intermediate voltage of a voltage provided to the inverting input terminal and a voltage provided to the non-inverting input terminal;
- a first current generation circuit and a second current generation circuit, to which an output signal of the common mode detection circuit is provided, which generate currents in accordance with the output signal;
- a first transistor having a control terminal coupled to an output terminal of the first current generation circuit;
- a second transistor having a control terminal coupled to an output terminal of the second current generation circuit;
- a third current source having one end coupled to a node between one end of the first transistor and the non-inverting output terminal;
- a fourth current source having one end coupled to a node between one end of the second transistor and the inverting output terminal;
- a first circuit coupled between the inverting input terminal and the non-inverting output terminal;
- and
- a second circuit coupled between the non-inverting input terminal and the inverting output terminal.
Dependencies are inferred from the claim text.