| 摘要 |
PURPOSE:To prevent a transistor from damaging at normal/reverse switching time by temporarily turning OFF all the transistors of a transistor bridge circuit in response to the variation of a control signal. CONSTITUTION:When the level of a signal A0 or A1 varies, a detector 14 detects the variation in the level of the signal A0 or A1 and outputs a differentiation signal B. A monostable multivibrator 26 is triggered by the signal B, and outputs a ''1'' level signal of the prescribed pulse width. Accordingly, the output of a decoder 12 becomes 0000, and transistors 36-41 of the transistor bridge circuit are turned OFF. When the output signal A1 of the multivibrator 26 becomes ''0'' after the prescribed time, the outputs D1-D3 of the decoder 12 becomes the prescribed state. Thus, excess current is not flowed to the transistors at the normal/reverse switching time. |
