Patent ID: 7915947

Claim:
A proportional to absolute temperature (PTAT) sensor, comprising: a control unit, for generating a control signal; a sensing unit, coupled to the control unit comprising: an amplifier having a first input end, a second input end, and an output end; a first transistor having a first collector, a first emitter, and a first base, wherein the first emitter is coupled to the first input end of the amplifier; a second transistor having a second collector, a second emitter, and a second base, wherein the second collector is coupled to the first collector, and the second emitter is coupled to the second input end of the amplifier; a first switch unit, coupled to the output end of the amplifier, the first transistor, and the second transistor, wherein the first switch connects the output end of the amplifier to the first transistor in a second connection configuration, or the first switch connects the output end of the amplifier to the second transistor in a first connection configuration according to the control signal; a current module, coupled to the first transistor and the second transistor, wherein the current module provides a first current to the first emitter and a second current to the second emitter under the first connection configuration, or the first current module provides the second current to the first emitter and the first current to the second emitter under the second connection configuration according to the control signal; wherein the sensing unit generates a first voltage value by sensing an absolute temperature under the first connection configuration, and generates a second voltage value by sensing the absolute temperature under the second connection configuration; and a calculation unit, coupled to the sensing unit, for calculating a PTAT voltage value according to the first voltage value and the second voltage value.