Class AB output stage
AssigneeInfineon Technologies AG
InventorDieter Draxelmayr
Life of this patent
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Abstract
This disclosure describes at least one class AB amplifier output stage circuit arrangement that can operate at low supply voltages, with minimum current generated. Furthermore, at least one class AB amplifier stage circuit arrangement described herein reacts favorably to a supply voltage, that is, exhibits a good power supply rejection ratio. Moreover, this disclosure describes class AB amplifier output stage circuit arrangements that include a negative channel metal oxide semiconductor (NMOS) transistor current mirror arrangement and a positive channel metal oxide semiconductor (PMOS) transistor current mirror arrangement. In some implementations, a monitoring circuit may be coupled to a class AB amplifier output stage circuit arrangement to offset mismatch that may occur in the class AB amplifier output stage.
Claims19
An apparatus comprising:
- a first operational transconductance amplifier to determine a voltage drop of a first impedance;
- a second operational transconductance amplifier to determine a voltage drop of a second impedance and wherein an output node of the second operational transconductance amplifier is coupled to an output node of the first operational transconductance amplifier;
- and
- at least one current source to adjust the voltage drop of the first impedance and the voltage drop of the second impedance and to provide a compensating current based on a difference between the voltage drop of the first impedance and the voltage drop of the second impedance.
An apparatus comprising:
- a differential amplifier arrangement coupled to a first impedance of an amplifier output stage and coupled to a second impedance of the amplifier output stage, wherein an output node of the differential amplifier arrangement is coupled to a variable current source arrangement and one or more input nodes of the differential amplifier arrangement are coupled to the first impedance and the second impedance, the differential amplifier arrangement to determine whether there is a difference between a voltage drop of the first impedance and a voltage drop of the second impedance.
A method comprising:
- generating an output signal of a first amplifier circuit based on a voltage drop of a first impedance;
- generating an output signal of a second amplifier circuit based on a voltage drop of a second impedance;
- and
- generating a compensating current when the voltage drop of the first impedance is different from the voltage drop of the second impedance, the compensating current to adjust the voltage drop of the first impedance, the voltage drop of the second impedance, or a combination thereof, such that the voltage drop of the first impedance and the voltage drop of the second impedance are to be adjusted to be approximately equal.
Dependencies are inferred from the claim text.