| 摘要 |
PURPOSE:To optionally set changes in output voltage due to temperature and, at the same time, to suppress the fluctuation of the output voltage caused by the fluctuation of a constant-current source, by providing a parallel circuit of two serial resistance bodies and a transistor whose base is connected with the connecting point of the two resistance bodies. CONSTITUTION:The reference voltage circuit of this invention is constituted in such a way that a parallel circuit of a serial body of resistances R5 and R4 and a transistor (Tr) Q4 whose base is connected to the connecting point of the resistances R5 and R4 is provided and a reference voltage is fetched from the collector side of the TrQ4 connected with a constant-current source CC. With this constitution, base-emitter voltages VBE3 and VBE4 of Trs Q3 and Q4 are equal to each other and, when these values are represented as VBE, the reference voltage VREF and temperature coefficient differential VREF/differential T are expressed by Formula I and Formula II, respectively. Since the coefficient (t) that is the variable of these formulae is a real number, an optical reference voltage can be set easily. Moreover, fluctuations of the voltage VREF can be suppressed to the utmost, since the variable part of the constant-current source CC almost goes to the TrQ3 and works to change the voltage VBE3 only. |
