Patent ID: 6717787
Filing Date: 2004-04-06
Classification: H03K

Abstract:
A power semiconductor device having a main current carrying transistor section integrated with a sense current carrying transistor section for carrying a current which is smaller than and indicative of the current carried by the main current carrying section, wherein the main transistor section and the sense transistor section have a common first main electrode connected to a first main terminal of the device, wherein the main transistor section and the sense transistor section have separate second main electrodes with the second main electrode of the main transistor section connected to a second main terminal of the device and the second main electrode of the sense transistor section connected through a current sensing resistance to said second main terminal of the device, wherein the main transistor section and the sense transistor section have separate control electrodes, wherein control means includes comparison means for comparing a reference voltage defining a current limit value with the voltage across the current sensing resistance and providing a first control signal, wherein the first control signal is coupled to the control electrode of the sense transistor section, wherein the first control signal is coupled to further control means which provides a second control signal coupled to the control electrode of the main transistor section, and wherein the further control means comprises adjustment circuit means coupled to the first control signal and to the voltage across the current sensing resistance and arranged to provide the second control signal such that the second control signal is effective to maintain the voltage between the control electrode and the second main electrode of the main transistor section equal to the voltage between the control electrode and the second main electrode of the sense transistor section.