| 摘要 |
PURPOSE: To provide a load drive apparatus by which an irregularity in the offset of a load drive operation due to an irregularity in a drive transistor and an irregularity in a gain are suppressed. CONSTITUTION: The polarity of an input signal Vi is removed in an absolute value circuit 1, and the input signal is converted into a current Ii by an input V/I circuit 2. On the other hand, the input signal Vi is converted into a polarity signal Sp indicating a polarity to be driven in a comparator 3. The current Ii is subtracted from the output of a feedback V/I circuit 8 in a subtracter 4, and it is changed into a voltage by an I/V circuit 9. A PWM conversion circuit decides pairs of transistors 6a to 6d driven by a drive circuit 6 on the basis of the polarity signal Sp and of the output of the I/V circuit 9. At this time, a feedback current If is generated by converting the output of a drive voltage detection circuit 7 into a current. At this time, as a ground neutral point for a current conversion operation, a point B or a point C at both ends of a load is selected by a changeover circuit 11 on the basis of the polarity signal Sp. |
