| 摘要 |
This invention relates to an overcurrent control technique for a power semiconductor device (1) such as an IGBT. The conventional overcurrent protection circuit (10P) has the problem that the current-carrying capacity of a MOSFET (2P) increases, causing an increase in surge voltage, when the emitter current (i) and the current sense current (is) do not exhibit the same behavior in a transient condition. In an overcurrent protection circuit (10P) for an IGBT (1) according to this invention, a diode (5) biased forwardly by a voltage higher than the threshold voltage of the MOSFET (2) is connected as a voltage clamping circuit (4) between the gate (2G) and source (2S) of the MOSFET (2P). When the voltage (is•Rs) across the sense resistor (3) rises above the forward voltage of the diode (5), therefore, the diode (5) conducts to clamp the gate voltage of the MOSFET (2) to a forward voltage.
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