Patent ID: 6107886
Filing Date: 2000-08-22
Classification: H03F

Abstract:
A power amplifier comprising:a pair of power-supply rails composed of a first power-supply line to which a power-supply potential regarded as an N-th potential is applied and a second power-supply line to which a ground potential is applied;a power-supply voltage divider for dividing a voltage between the power-supply rails into first to (N-1)th potential which are sequentially higher from the first potential toward the (N-1)th potential;an (N-1) number of intermediate power-supply line or lines to which the first to (N-1)th potentials are applied, respectively;first to N-th BTL amplifiers connected to receive first to N-th channel signals, respectively, said first to N-th BTL amplifiers including output bridge circuits provided corresponding to the first to N-th BTL amplifiers, respectively, stacked one above another and connected between the power-supply rails; andswitching circuits provided corresponding to the first to N-th BTL amplifiers, respectively, each designed to connect the output bridge circuit between one potential and the immediately higher potential when the BTL amplifier has no signals, and to change connection of the output bridge circuit when an output voltage level of the BTL amplifier increases, where N is integer .gtoreq.2.