| 摘要 |
PURPOSE:To attain the actuation at a low level of voltage for a writing circuit for floppy disk by using a voltage output circuit which sets a pnpTR between a common terminal of a magnetic head and a power supply and flows a current to the middle point of a coil and a common emitter TR which flows out currents alternately from both terminals of the coil. CONSTITUTION:Voltage output circuits 58A and 58B are provided to impressing voltage to a common terminal for each of magnetic heads 2A and 2B, and current switch circuits 60A and 60B switch the currents supplied to both heads 2A and 2B respectively. The circuit 58A consists of a pnpTR62, a resistance and a switch 68A. A constant current of a constant current source 104 is inverted by a constant current circuit consisting of TRs 106, and 108 and supplied to TRs 78, 80, 92 and 94 respectively. The active voltage impressed to the head 2A is increased up to 4.5V although the power supply voltage VCC is lowered down to 5V. This attains the drive at a low level of voltage. Thus it is possible to drive a writing circuit for floppy disk with a portable power supply such as dry cells, etc. Then a portable floppy disk device is obtained. |
