| 摘要 |
A semiconductor switching circuit is disclosed which switches current from a power source through a load in response to switching control signals applied to first and second semiconductor switching devices, such as transistors. The first and second transistors are connected in series and the first transistor has a higher voltage rating but lower switching speed than the second transistor. A voltage limiting device, such as a further transistor, effectively limits the voltage across the second transistor so that its voltage rating is not exceeded and also so as to remove stored charge in the base region of the first transistor which would otherwise tend to hold the transistor on. This technique increases the switching speed of the circuit and allows a high voltage and current handling device to be selected for the first transistor, and a high current, high speed device to be selected for the second transistor.
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