| 摘要 |
The present invention relates to the activation and deactivation of a transistor (Q1) in a final stage (10), for instance a push-pull final stage. The final stage is included in a voltage alternating drive system connected to a load. A current driving buffer circuit (24) in the drive system is connected to the transistor (Q1) and functions to activate and deactivate the transistor, i.e. to switch the transistor on and off, in a manner such as to generate only a low power loss in the transistor, even when the load is inductive. The current driving buffer circuit (24) includes a first inverting circuit (Q3, Q4), a second inverting circuit (Q5, Q6), a current generating circuit (Q7, Q8), and a semiconductor element (Q9). The inverting circuits coact with the current generating circuit (Q7, Q8) to switch off the transistor (Q1), wherein the current generating circuit generates a deactivation current (IDIS) which charges capacitances (CGSQ1, CGDQ1) in the transistor (Q1) very rapidly, so that the voltage (OUTLSB) on an input of the transistor (Q1) will increase to a deactivation level (VCCH). The inverting circuits coact with the semiconductor element (Q9) to activate or switch on the transistor (Q1), wherewith the semiconductor element generates an activation current (ICON) which charges the capacitances (CGSQ1, CGDQ1) in the transistor (Q1), so that the voltage (OUTLSB) on an input of the transistor (Q1) falls to an activation level (VREG). |
