US Patent 11296212 Semiconductor device and power conversion device

A current switching semiconductor device to be used in a power conversion device achieves both a low conduction loss and a low switching loss. The semiconductor device includes the IGBT in which only Gc gates are provided and an impurity concentration of the p type collector layer is high, and the IGBT in which the Gs gates and the Gc gates are provided and an impurity concentration of the p type collector layer is low. When the semiconductor device is turned off, the semiconductor device transitions from a state in which a voltage lower than a threshold voltage is applied to both the Gs gates and the Gc gates to a state in which a voltage equal to or higher than the threshold voltage is applied to the Gc gates prior to the Gs gates.