Signal detection circuit and signal detection method
A signal detection circuit includes: a power terminal; a first current limitation circuit; a second current limitation circuit; a current-voltage conversion circuit; a first p-channel MOS transistor including a source, a gat, and a drain; a first n-channel MOS transistor including a drain, a gate, and a source; and a second n-channel MOS transistor in which a drain is connected to a first connection point connecting the resistor with the drain of the first n-channel MOS transistor, a gate is connected to a second connection point connecting the drain of the first p-channel MOS transistor with the current-voltage conversion circuit, and a source is grounded.
1. A signal detection circuit comprising:
a power terminal;
a first current limitation circuit connected to the power terminal;
a second current limitation circuit;
a resistor connected to the power terminal;
a current-voltage conversion circuit;
a first p-channel MOS transistor including a source connected to the power terminal via the first current limitation circuit, a gate to which a voltage changing in accordance with a change in a voltage level of an input voltage is supplied, and a drain grounded via the current-voltage conversion circuit;
a first n-channel MOS transistor including a drain connected to the power terminal via the resistor, a gate to which the voltage changing in accordance with the change in the voltage level of the input voltage is supplied, and a source grounded via the second current limitation circuit; and
a second n-channel MOS transistor in which a drain is connected to a first connection point connecting the resistor with the drain of the first n-channel MOS transistor, a gate is connected to a second connection point connecting the drain of the first p-channel MOS transistor with the current-voltage conversion circuit, and a source is grounded.
2. The signal detection circuit according to claim 1 ,
wherein the first current limitation circuit includes a first constant current source circuit and a first capacitor connected in parallel, and
wherein the second current limitation circuit includes a second constant current source circuit and a second capacitor connected in parallel.
3. The signal detection circuit according to claim 2 ,
wherein the current-voltage conversion circuit includes a third n-channel MOS transistor in which each of a gate and a drain are connected to the drain of the first p-channel MOS transistor and the gate of the second n-channel MOS transistor, and a source is grounded.
4. The signal detection circuit according to claim 3 , further comprising:
a third current limitation circuit; and
a second p-channel MOS transistor in which a source is connected to the power terminal, a gate is connected to the first connection point, and a drain is grounded via the third current limitation circuit.
5. The signal detection circuit according to claim 2 , further comprising:
a third current limitation circuit; and
a second p-channel MOS transistor in which a source is connected to the power terminal, a gate is connected to the first connection point, and a drain is grounded via the third current limitation circuit.
6. The signal detection circuit according to claim 1 ,
wherein the current-voltage conversion circuit includes a third n-channel MOS transistor in which each of a gate and a drain are connected to the drain of the first p-channel MOS transistor and the gate of the second n-channel MOS transistor, and a source is grounded.
7. The signal detection circuit according to claim 3 , further comprising:
a third current limitation circuit; and
a second p-channel MOS transistor in which a source is connected to the power terminal, a gate is connected to the first connection point, and a drain is grounded via the third current limitation circuit.
8. The signal detection circuit according to claim 1 , further comprising:
a third current limitation circuit; and
a second p-channel MOS transistor in which a source is connected to the power terminal, a gate is connected to the first connection point, and a drain is grounded via the third current limitation circuit.
9. A signal detection method, using a signal detection circuit including a power terminal, an input terminal, a first current limitation circuit connected to the power terminal, a second current limitation circuit, a resistor connected to the power terminal, a current-voltage conversion circuit, a first p-channel MOS transistor including a source connected to the power terminal via the first current limitation circuit, a gate to which a voltage changing in accordance with a change in a voltage level of an input voltage is supplied, and a drain grounded via a current-voltage conversion circuit, a first n-channel MOS transistor including a drain connected to the power terminal via the resistor, a gate to which a voltage changing in accordance with the change in the voltage level of the input voltage is supplied, and a source grounded via the second current limitation circuit, and a second n-channel MOS transistor in which a drain is connected to a first connection point connecting the resistor with the drain of the first n-channel MOS transistor, a gate is connected to a second connection point connecting the drain of the first p-channel MOS transistor with the current-voltage conversion circuit, and a source is grounded, comprising of:
amplifying a change in a signal voltage supplied from the input terminal to a positive voltage side by the resistor and the first n-channel MOS transistor; and
amplifying a change in a signal voltage supplied from the input terminal to a negative voltage side by the resistor and the second n-channel MOS transistor.
10. The signal detection method according to claim 9 ,
wherein the first current limitation circuit includes a first current limitation circuit and a first capacitor connected in parallel, and
wherein the second current limitation circuit includes a second current limitation circuit and a second capacitor connected in parallel.