| 摘要 |
PURPOSE:To realize a reference voltage generating circuit which uses the band gap voltage of an Si semiconductor which is coupled with a power source at its collector terminal and suitable for integration, by detecting the emitter current of an NPN transistor (TR). CONSTITUTION:A power voltage is supplied between a power terminal 207 and an earth terminal 208. Through the negative feedback of a differential amplifier 206, terminals of resistances 204 and 205 are held at the same potential and the ratio of emitter currents of TRs 201 and 202 is equal to the ratio of the resistances 205 and 204. The emitter current of the TR201 is determined by a voltage applied to a resistance 203. i.e. the difference in base-emitter voltage between the TRs 201 and 202. The voltage between an output terminal 209 and the earth terminal 208 is the sum of the base-emitter voltage of the TR202 and the terminal voltage across the resistance 205. Then, the ratios of resistances R1 and R2, and R1 and R3, and the emitter area ratio of the TRs 201 and 202 are set properly to generate a reference voltage ( 1.2V) nearly equal to the band gap voltage of Si. |
