| 摘要 |
<p>An inductive load (12) is disposed between a midpoint (P1) between a first and a second transistor (14, 16) connected in series and a midpoint between a third and a fourth transistor (15, 17) connected in series. A protective resistor is disposed between sources or emitters of the first and third transistors (14, 15) and a direct-current power supply (Vcc), and a sensing resistor (R2) is disposed between low-potential sides of the second and fourth transistors (14, 17) and ground. The first and third transistors (14, 15) are driven through input of drive signals, each having a fixed potential, to gates or bases thereof. The drive signals from the drive means are turned off when, during powering of the inductive load (12), a voltage applied to the sensing resistor (R2) is continuously equal to or lower, for a predetermined period of time or longer, than a threshold value for ground short detection. Breakdown of the first and third transistors(14, 15) on account of ground shorts is thus prevented by way of a simple circuit.</p> |
