Patent ID: 7643261

Claim:
A semiconductor device comprising: a first input circuit unit, a second input circuit unit, wherein the first input circuit unit includes: a first external terminal supplied with a first analog input signal generated in a first external circuit operating on a first power supply voltage; a first electrostatic discharge protection circuit corresponding to the first analog input signal; a first voltage divider resistor for dividing the first analog input signal passing through the first electrostatic discharge protection circuit into a voltage corresponding to a second power supply voltage lower than the first power supply voltage; a first input circuit that operates on the second power supply voltage and receives the first analog input signal divided by the first voltage divider resistor to generate a first internal analog signal; a first unidirectional element for passing current from an input terminal of the first input circuit to the first power supply voltage; a second unidirectional element for passing current from a circuit ground potential to an input terminal of the first input circuit; a resistor transmitting the analog input signal passing through the first electrostatic discharge protection circuit; a second input circuit that operates on the first power supply voltage and receives the first analog input signal passing through the resistor to generate a second internal analog signal; a third unidirectional element for passing current from an input terminal of the second input circuit to the first power supply voltage; and a fourth unidirectional element for passing current from a circuit ground potential to an input terminal of the second input circuit; a second external terminal supplied with a second analog input signal formed in the first external circuit; a second electrostatic discharge protection circuit corresponding to the second analog input signal; a second voltage divider resistor for dividing the second analog input signal passing through the second electrostatic discharge protection circuit into a voltage corresponding to a third power supply voltage; a third input circuit that operates on the third power supply voltage and receives the second analog input signal divided by the second voltage divider resistor to generate a third internal analog signal; a fifth unidirectional element for passing current from an input terminal of the third input circuit to the first power supply voltage; and a fourth unidirectional element for passing current from a circuit ground potential to an input terminal of the third input circuit, wherein the second input circuit unit includes: a third external terminal supplied with a third analog input signal generated in a second external circuit operating on the second power supply voltage; a third electrostatic discharge protection circuit corresponding to the third analog input signal; and a fourth input circuit that operates on the second power supply voltage and receives the third analog input signal to generate a fourth internal analog signal.