Patent ID: 6061218
Filing Date: 2000-05-09
Classification: H01L,H02H

Abstract:
An overvoltage protection device, comprising:a Silicon Controlled Rectifier (SCR) having an anode, a cathode, an input, and an output, wherein the SCR comprises:a first transistor having a control electrode coupled to the output of the SCR, a first current carrying electrode coupled to the anode of the SCR, and a second current carrying electrode coupled to the input of the SCR; anda second transistor having a control electrode coupled to the input of the SCR, a first current carrying electrode coupled to the control electrode of the first transistor, and a second current carrying electrode coupled to the cathode of the SCR;an SCR enhance circuit having a first input coupled to the anode of the SCR, a second input coupled to the output of the SCR, and an output coupled to the input of the SCR,wherein the SCR enhance circuit comprises:a third transistor having a control electrode coupled to the second input of the SCR enhance circuit, a first current carrying electrode coupled to the first input of the SCR enhance circuit, and a second current carrying electrode coupled to the output of the SCR enhance circuit, wherein a current gain of the third transistor is greater than a current gain of the first transistor.