| 摘要 |
PURPOSE:To obtain a stable output by shiting the level of a constant potential difference caused by a constant current flowing to a resistor while utilizing a forward voltage of a transistor (TR) arry or a diode array so as to form a TTL low level output voltage. CONSTITUTION:In impressing an ECL high level input signal to an input terminal IN, an input signal of a current switch circuit comprising TRs Q4, Q5 is impressed to a base of the TR Q4, which is turned on and the TR Q5 receiving a reference voltage V at its base is turned off. Thus, the current of a constant current source circuit comprising a TR Q6, a resistor R3, a reference voltage VCS flows from a positive power supply Vcc to a path comprising a resistor R2 and TRS Q2, Q4. A TTL low level is outputted at an output terminal OUT and its voltage is VOL=VBQ1-VD1-VD2-VD3 (VD1=VD2= VD3: forward voltage of the diode with a current ID flowing) and a stable low level output is obtained. |
