Dynamic element matching of bipolar junction transistors for improved proportional to absolute temperature voltage determination

A method for determining a temperature, the method comprising:

• for each of a plurality of transistors arranged in parallel, each of the plurality of transistors having an emitter and a base, the emitter of each of the plurality of transistors selectively coupled to a current source via a respective one of a plurality of switches such that a bias current flows from the current source to the emitter of a respective one or more of the plurality of transistors when a respective one or more switches is closed, separately measuring a base-emitter voltage (VBE) when all the switches are closed and a VBE when only the switch associated with each transistor is closed;
• determining a ΔVBE for each of the plurality of transistors by calculating, for each of the plurality of transistors, a difference between the VBE when only the switch associated with each transistor is closed and the VBE when all the switches are closed;
• calculating an average of all of the determined ΔVBEs;
• and
• calculating a temperature using the average of all of the determined ΔVBEs.

A temperature sensor comprising:

• a current source;
• a plurality of transistors arranged in parallel, each of the plurality of transistors having an emitter and a base;
• a plurality of switches, each of the plurality of switches selectively coupling the current source to the emitter of a corresponding one of the plurality of transistors such that a bias current flows from the current source to the emitter of a respective one or more of the plurality of transistors when a respective one or more switches is closed;
• switch control circuitry configured to, at different times, cause all the switches to close and, separately for each transistor, cause the switch associated with each transistor to close while causing all other switches to open;
• and
• measurement circuitry coupled to each of the plurality of transistors between each respective switch and the emitter of each respective transistor, the measurement circuitry configured to measure, separately for each of the plurality of transistors, a base-emitter voltage (VBE) when all the switches are closed and a VBE when only the switch associated with each transistor is closed, the measurement circuitry further configured to determine a ΔVBE for each of the plurality of transistors by calculating, for each of the plurality of transistors, a difference between the VBE when only the switch associated with each transistor is closed and the VBE when all the switches are closed, the measurement circuitry further configured to calculate an average of all of the determined ΔVBEs.