Patent ID: 8982497
Filing Date: 2015-03-17
Classification: G11B,H02P,H03F

Abstract:
1. A class-AB amplifier comprising: an upper side transistor which is connected between an application terminal of a first power supply voltage and an application terminal of an output voltage; a lower side transistor which is connected between an application terminal of a second power supply voltage and the application terminal of the output voltage; a linear driver which generates an upper side gate voltage and a lower side gate voltage varying continuously with reverse polarity in accordance with an input voltage and a reference voltage to output the upper side gate voltage and the lower side gate voltage to the upper side transistor and the lower side transistor; an upper side idler which biases the upper side gate voltage by applying an upper side bias current between an application terminal of the upper side gate voltage and the application terminal of the output voltage so as to turn on the upper side transistor in a crossover region between the input voltage and the reference voltage; a lower side idler which biases the lower side gate voltage by applying a lower side bias current between an application terminal of the lower side gate voltage and the application terminal of the second power supply voltage so as to turn on the lower side transistor in the crossover region; an upper side detection current generator which generates an upper side detection current in accordance with the upper side bias current; a lower side detection current generator which generates a lower side detection current in accordance with the lower side bias current; and an off driver which controls the lower side gate voltage so as to reduce a degree of conduction of the lower side transistor as the upper side detection current is larger, and controls the upper side gate voltage so as to reduce a degree of conduction of the upper side transistor as the lower side detection current is larger.