Patent ID: 6906902

Claim:
A semiconductor integrated circuit comprising: a transistor which has a first electrode, a second electrode and a third electrode, said transistor conducting a current of a first power source from said second electrode to said third electrode by a power supplied to said first electrode; a driver configured to supply said first electrode with power for driving said transistor; a reference voltage circuit configured to generate a reference voltage which is variable in response to temperature of said transistor, said reference voltage being used as the reference for comparison, said reference voltage circuit including a heat-sensitive element which is disposed on a common chip together with said transistor to generate a potential difference depending upon temperature of said transistor; a comparative voltage circuit configured to generate a comparative voltage which is variable in response to a current flowing from said second electrode to said third electrode, said comparative voltage being compared with said reference voltage; a controller which receives said reference voltage and said comparative voltage and which supplies a control signal to said driver, said control signal being based on a result of the comparison between the comparative voltage and the reference voltage to control the power supplied to said first electrode; and a constant current circuit which flows a constant current to said heat-sensitive element; wherein said heat-sensitive element intervenes in series in the line from said first power source to said constant current circuit, wherein said reference voltage circuit includes first and second loads which are connected in series to each other and connected in parallel to said heat-sensitive element, wherein said reference voltage is obtained by dividing the potential difference across opposite ends of said heat-sensitive element at a node between said first and second loads, and wherein said controller includes a comparator which compares said reference voltage and said comparative voltage to output a result of the comparison to said driver.