| 摘要 |
PURPOSE:To prevent the short circuit of a power supply or the breakdown of a transistor due to the malfunction of a control circuit for the transistor by mounting the transistor control circuit using a signal from the power supply driving a Hall element as a reference signal on the base side of the transistor supplying a coil with currents. CONSTITUTION:The terminal voltage of a resistor 8 for limiting currents for a power supply Vcc2 for Hall elements 2U-2W is inputted to AND gates 10U-10W, 10U'-10W' through a buffer 11, ANDs with transistor drive-signals from AND gates 5U-5W, 5U'-5W' are taken, and outputs from the AND gates 5U-5W, 5U'-5W' are employed as drive signals for transistors 6U-6W, 6U'-6W'. When a motor M is not connected through a connector 9, the terminal voltage of the resistor 8 reaches 0, thus bringing all of the transistors 6U-6W, 6U'-6W' to an OFF state. |
