| 摘要 |
<p>A drive circuit is disclosed for supplying a drive signal to the gate of a semiconductor switching device such as an IGBT or a MOSFET. The circuit comprises: a plurality of gate impedance circuits 40a, b, c and 42a, b, c selectably connectable to the gate of the semiconductor switching device 2, and a selector (e.g. a microprocessor 8, fig.1) to select one or more of the gate impedance circuits. The turn-on and turn-off times may be independently controlled. The micro-processor may control a number of gate impedance circuits for a plurality of devices 2. The associated method comprises selecting and connecting one or more of a plurality of gate circuits to the base of a switching device based on operating conditions and on stored data relating to the operating conditions. The components in the base drive circuit may thus be selected, in use, to provide or compensate for the cable length of an attached load, or to maintain relatively constant power loss in a switching device at different loads, and hence reduced thermal fatigue, or to minimise conducted or radiated emissions (RFI).</p> |
