Driver circuit and switch system

A driver circuit for a semiconductor switching element of a current driven type, the semiconductor switching element including a gate and a source corresponding to the gate, the driver circuit comprising:

• a power supply terminal;
• a ground terminal configured to be connected to the source of the semiconductor switching element;
• a signal input terminal;
• a first field effect transistor connected to the power supply terminal;
• a second field effect transistor connected in series to the first field effect transistor and configured to be connected to the gate of the semiconductor switching element;
• and
• an impedance element configured to be provided between the signal input terminal and a node, the node being between the second field effect transistor and the gate of the semiconductor switching element,
• the driver circuit being configured such that when a voltage level of a signal input to the signal input terminal changes from a first potential level to a second potential level higher than the first potential level with the second field effect transistor being in an ON state,
• the first field effect transistor is on, and the driver circuit thus causes a current larger than a current flowing through the impedance element to flow through the gate of the semiconductor switching element such that the gate voltage of the semiconductor switching element is increased to a value higher than a prescribed value higher than a value of the threshold voltage, and thereafter,
• the driver circuit keeps the current flowing through the gate of the semiconductor switching element via the impedance element from the signal input terminal such that the semiconductor switching element is in the normally ON state.