| 摘要 |
<p>PURPOSE:To attain high speed operation and expansion of noise margin by using a signal obtained from a collector output of a differential transistor (TR) at an input signal side via an emitter follower circuit as a reference voltage of the differential TR circuit. CONSTITUTION:A collector output of the differential TR Q1 is fed to a base of the emitter follower circuit TR Q3. A load resistor R3 is provided between the emitter of the TR Q3 and a voltage terminal -Vee and the emitter output of the TR Q3 is fed back to a base of a differential TR Q2. In other words, the emitter output of the TR Q3 is used as a reference voltage for the logic circuit. In using the reference voltage formed in this way, the logic circuit constituted as above acts like a Schmitt trigger circuit. Further, the input/output transmission characteristic having a hysteresis characteristic is obtained. Thus, the high current switching speed is realized in this way. Since the range of the hysteresis width is made immune against noise by means of the input/output transmission characteristic and the positive feedback characteristic, the noise immunity is improved.</p> |
