Semiconductor device
A semiconductor device has: a power supply line; a ground line; a signal line for transmitting a signal; a signal pad connected to the signal line; a protection element connected between the signal line and the ground line; and a trigger circuit configured to supply a trigger current to the protection element. The trigger circuit has: a PMOS transistor whose gate and backgate are connected to the power supply line and whose source is connected to the protection element; and an amplifier circuit part configured to amplify a first current flowing through the PMOS transistor to generate a second current. The trigger current includes the second current.
1. A semiconductor device comprising:
a power supply line;
a ground line;
a signal line for transmitting a signal;
a signal pad connected to said signal line;
a protection element connected between said signal line and said ground line; and
a trigger circuit configured to supply a trigger current to said protection element,
wherein said trigger circuit comprises:
a PMOS transistor whose gate and backgate are connected to said power supply line and whose source is connected to said protection element; and
an amplifier circuit part configured to amplify a first current flowing through said PMOS transistor to generate a second current,
wherein said trigger current includes said second current.
2. The semiconductor device according to claim 1 ,
wherein said amplifier circuit part of said trigger circuit comprises:
a first node connected to a drain of said PMOS transistor;
a first resistor element connected between said first node and said ground line; and
a first NMOS transistor whose drain is connected to said protection element, whose source is connected to said ground line and whose gate is connected to said first node.
3. The semiconductor device according to claim 2 ,
wherein said amplifier circuit part further comprises:
a second node connected to said gate of said PMOS transistor;
a second resistor element connected between said second node and said power supply line; and
a switch element configured to provide, in response to potential of said first node, a current path between said second node and said ground line.
4. The semiconductor device according to claim 3 ,
wherein said switch element comprises a second NMOS transistor whose drain is connected to said second node, whose gate is connected to said first node and whose source is connected to said ground line.
5. The semiconductor device according to claim 1 ,
wherein a parasitic diode or a diode element is connected between said signal line and said power supply line.
6. The semiconductor device according to claim 1 ,
wherein said protection element is a thyristor.
7. The semiconductor device according to claim 1 ,
wherein said PMOS transistor does not perform a parasitic bipolar operation when generating said first current.
8. The semiconductor device according to claim 2 ,
wherein said first NMOS transistor does not perform a parasitic bipolar operation when generating said second current.
9. The semiconductor device according to claim 4 ,
wherein said second NMOS transistor does not perform a parasitic bipolar operation when providing said current path.