Patent ID: 7688561
Filing Date: 2010-03-30
Classification: H03K

Abstract:
1. An over-voltage protection circuit, comprising: a first switching block having a plurality of semiconductor elements serially connected to each other and turned on in sequence according to the magnitude of an input voltage; and a plurality of second switching blocks, in which each of the second switching blocks includes a pair of serially connected semiconductor elements having different current properties, and is connected to the first switching block; wherein each of the second switching blocks comprises a MOSFET device and a bipolar junction transistor (BJT) serially connected to the MOSFET device, wherein each of the second switching blocks is connected to the first switching block through a gate of the MOSFET device; wherein the bipolar junction transistors are turned on in sequence according to the magnitude of the input voltage, and wherein a base of at least one bipolar junction transistor in at least one of the second switching blocks is connected to an emitter of a bipolar junction transistor in another one of the second switching blocks.