| 摘要 |
A pair of ratioed emitter size transistors is operated to produce a DELTA VBE. A second pair of transistors is coupled in series with the first pair and matched therewith so as to produce 2 DELTA VBE. This differential voltage appears across a resistor coupled in series with the low current density transistors. This circuit combination produces a current that is proportional to absolute temperature (PTAT) and which is passed through a suitable value resistor to develop a PTAT voltage. This voltage is combined with a negative temperature coefficient voltage produced by forward biased series connected diodes so as to produce a combined voltage that is a multiple of the semiconductor bandgap extrapolated to absolute zero. The diodes are operated at very low current levels so that the circuit requires a very low operating current.
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