Short circuit protection circuit for semiconductor element

Abstract

Abstract PURPOSE:To prevent latchup breakdown at the time of load short circuit by a method wherein, when a short circuit current flows between a collector and an emitter, a protective transistor turns ON, and the gate voltage is divided by a gate resistor and a dividing resistor. CONSTITUTION:The emitter cell of an insulated gate type bipolar transistor Tr is divided into emitters E1 and E2. When a collector current flows as a part of short current between the collector terminal C and the emitter terminal E of the transistor Tr, a part of the current flows also in a current detection resistor Rs. When the voltage between both terminals of the resistor Rs exceeds the conduction voltage of a protective transistor Tr1, it turns ON. When the transistor Tr1 turns ON, an input voltage Vin applied to the gate terminal G of Tr is divided by a gate resistor Rg and a resistor Rd. As a result, the gate voltage applied to the terminal G of Tr is decreased, and the short current is reduced, so that the current density in Tr is decreased, thereby protecting the transistor Tr from latchup breakdown.

Inventors

• 👤 Masanori Fukunaga
• 👤 福永　匡則

Bibliographic Details