| 摘要 |
PURPOSE:To drive a loudspeaker of class B operation with low power consumption, by connecting an operation amplifier to each of two outputs of a D/A converter and connecting a voice coil between the outputs of the amplifiers. CONSTITUTION:In a B-class loudspeaker driving circuit, a circuit having a high output impedance outputting either one of potentials dividing equally a full scale into 2<n-1> with (n-1) sets of weighted digital input signals MSB, 2SB, LSB, and four switches SM.M, SW.-M, SWB and SWC controlled with ''1'' or ''0'' of one digital signal with the highest weight from the output of the circuit, outputting ground level for one and transmitting output level for the others, constitute an n-bit D/A converter. To two outputs of the converter, operational amplifiers OP1 and OP2 are respectively connected and a voice coil is connected between the operational amplifiers OP1 and OP2. |
