| 摘要 |
PURPOSE:To achieve direct driving of a TTL logical circuit with an output of a differential pair transistors (TRs), by connecting a constant current load to the collector of the differential pair TRs receiving an input signal. CONSTITUTION:A constant current load I0 flowing a 1/2 current of the constant current source 2I0 to the collector of differential pair transistors Q1 and Q2 to the emitter of which the constant current source 2I0 is connected, is provided. To the collectors of the TRs Q1 and Q2, an inverter circuit consisting of input TRs Q3 and Q6, output TRs Q4, Q5, Q7 and Q8, diodes D1, D2, D3 and D4, and a resistor is connected. When an input signal Vin is greater than a reference signal Vref, the TRQ1 turns on and the Q2 turns off and the load constant current at the Q1 side all passes through the TRQ1, then the input TRQ6 turns off and an output OUT attains high level. |
