| 摘要 |
PURPOSE:To prevent the title driving gear from being burnt and damaged when two transistors on one side of an H-bridge circuit are turned on simultaneously. CONSTITUTION:Signals from a CPU 10 are designated as the following: a first instruction signal A which instructs either a forward rotation operation or a reverse rotation operation as the direction of rotation; and a second instruction signal B which instructs either a rotation operation or a holding operation. According to the combination of the first and second instruction signals A, B, a first transistor to a fourth transistor Tr1 to Tr4 are controlled so as to be turned on and off. That is to say, when the second instruction signal R is set to the holding operation (T,), all the first to fourth transistors Tr1 to Tr4 are turned off. When the second instruction signal R is set to the rotation operation (H) and the first instruction signal A is set to the forward rotation operation (H), the second and third transistors Tr2, Tr3 are turned on. When the second instruction signal B is set to the rotation operation (H) and the first instruction signal A is set to the reverse rotation operation (L), the first and fourth transistors Tr1, Tr4 are turned on. |
