Patent ID: 6836186
Filing Date: 2004-12-28
Classification: H03F

Abstract:
An AB class buffer amplifier capable of controlling quiescent current, the AB class buffer amplifier comprising:a first current controller which sources current to an output node in response to a first logic level of a first signal, and buffers and outputs an input voltage to the output node in response to a second logic level of the first signal; and a second current controller which sinks the current from the output node in response to a second logic level of a second signal, and buffers and outputs the input voltage to the output node in response to a first logic level of the second signal; wherein the first current controller comprises: a first transistor, a first node of which is connected to a power voltage; a second transistor, a first node of which is connected to a second node of the first transistor, a gate of which is supplied with the first signal, and a second node of which is connected to a gate of the first transistor; a third transistor, a first node of which is connected to the power voltage, a gate of which is connected to a gate of the first transistor, and a second node of which is connected to the output node; and a first current source which is connected between the second node of the second transistor and a ground voltage, and generates a first bias current.