Patent ID: 7541861

Claim:
In a temperature sensor, a method of matching transistors to generate currents of a known ratio, said method comprising: generating a control signal from a control circuit, wherein said control signal comprises a value that defines a configuration; detecting whether said value of said control signal has changed; and provided said value has changed, switching a plurality of transistors from one configuration to a different configuration, wherein there are at least four transistors in said plurality of transistors and wherein a first configuration comprises connecting said at least four transistors in parallel and a second configuration comprises connecting the same said at least four transistors in series, wherein said first configuration produces a first current in a first circuit and in a second circuit, wherein said second configuration produces a second current in said first circuit and in said second circuit, wherein the ratio of said first current to said second current is said known ratio, and wherein said ratio of said first current to said second current is used to determine a temperature at a device coupled to said plurality of transistors.