| 摘要 |
PURPOSE:To apply a voltage which is symmetrical at positive and negative components to the Hall element of a transistor motor by providing two operational amplifier which are connected to each other via a resistor to the input terminal of a midpoint voltage supplying means and buffer amplifiers provided at the respective operational amplifiers. CONSTITUTION:When an external control signal voltage VE is equal to the midpoint voltage VM, the outputs of operational amplifiers 23, 24 become 0, a midpoint voltage VM (=VE) is applied to the control terminal J of the Hall elements 1-3, thereby obtaining VJ=VM, and the voltage VK of another control terminal K of the Hall elements 1-3 also similarly becomes VM. If the VE is lower than the VM, the VJ becomes higher by the voltage across a resistor 29 (VM-VE) than the VM, while the VK becomes lower by (VM-VE) than the VM. Accordingly, the current is flowed from the terminal J to the Hall elements 1-3, and the motor is, for example, rotated normally. On the contrary, if the VE is higher than the VM, the VJ becomes lower by (VM -VE) than the VM and the VK becomes higher than the VM. Consequently, the current is flowed from the terminal K to the Hall elements 1-3, and the motor is inverted. |
