| 摘要 |
A programmable reference voltage circuit includes a reference voltage output terminal, a ground terminal, and a power terminal, where the power terminal is connected through a current source to the reference voltage output terminal. The programmable reference voltage circuit further includes first, second and third bipolar transistors. The first bipolar transistor is connected by way of its collector through a first resistance to the reference voltage output terminal, and is connected by way of its emitter to the ground terminal. The second bipolar transistor is connected by way of its collector through a second resistive element to the reference voltage output terminal, and is connected by way of its emitter to the ground terminal. The third bipolar transistor is connected the reference voltage output terminal, the second bipolar transistor, and the ground terminal. A resistive element selecting circuit is connected between the emitter of the second bipolar transistor and the ground terminal, and includes a plurality of selectable resistive elements connected in parallel, with each one having a different resistance value. The selecting circuit is capable of selecting any particular one of the selectable resistive elements, so as to achieve a particular reference voltage.
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