Protection circuit, and semiconductor device and light emitting device using such protection circuit

A semiconductor device comprising:

• a driver circuit which is connected to a cathode of a light emitting diode and which controls emitted quantity of light of the light emitting diode;
• and
• a protection circuit provided with the driver circuit as a circuit to be protected, connected via a line including a significant inductance component to the driver circuit, the protection circuit comprising:
• a first transistor arranged on a path to ground from a connection point of the protection circuit and the line;
• and
• a second transistor arranged on a path to ground from a connection point of the driver circuit and the line, the second transistor extracting, from the connection point, a current corresponding to a current flowing in the first transistor.

A light emitting apparatus comprising:

• a light emitting diode;
• and
• a semiconductor device which drives the light emitting diode, the semiconductor device comprising:
• a driver circuit which is connected to a cathode of a light emitting diode and which controls emitted quantity of light of the light emitting diode;
• and
• a protection circuit provided with the driver circuit as a circuit to be protected, connected via a line including a significant inductance component to the driver circuit, the protection circuit comprising:
• a first transistor arranged on a path to ground from a connection point of the protection circuit and the line;
• and
• a second transistor arranged on a path to ground from a connection point of the driver circuit and the line, the second transistor extracting, from the connection point, a current corresponding to a current flowing in the first transistor.