Protective circuit for input to mis type field-effect semiconductor device

Abstract

Abstract PURPOSE:To disperse power by excess input voltage, and to improve protective capacity to input protective resistors by connecting a series circuit consisting of the third input protective resistor and a diode at a node between the first and second input protective resistors. CONSTITUTION:A first series circuit composed of a third input protective resistor 12 and a diode 13 and a second series circuit consisting of a fourth input protective resistor 14 and a diode 15 are connected at a node 11 between first and second input protective resistors 9, 10. When positive excess input voltage 8 is applied to an input terminal 7, currents flow through the second input protective resistor 10, are branched by the third input protective resistor 12 and the first input protective resistor 9, and rapidly flow out through diodes 13, 5. When negative excess input voltage is applied to the input terminal 7, on the other hand, currents are branched by the fourth input protective resistor 14 and the first input protective resistor 9, and quickly flow out through diodes 15, 6. Accordingly, input voltage is clamped, and a gate 2 in an MIS.FET1 is protected so that voltage of dielectric breakdown withstanding voltage or higher is not applied.

Inventors

• 👤 Takenori Okidaka
• 👤 毅則 沖高

Bibliographic Details