| 摘要 |
PURPOSE:To freely enable to set the threshold voltage of I<2>L element, by inserting the input interface circuit between the base of the NPN transistor being the input section of I<2>L element and the control logic device. CONSTITUTION:The emitter of the transistor TR51 of the input interface circuit 50 is connected to the reference power supply Vref via the resistor R, and when the output of the logic control device consisting of TTL is fed to the terminal 12, Vref is set to the value corresponding to the threshold voltage Vth specific to TTL. When the input voltage Vin > Vref, TR51 and 11 are turned off and the output Vout is at ''H''. On the other hand, when Vin is lower than Vref by VBE of TR51, TR51 and 11 are turned on and the output Vout is at ''L''. That is, when Vth is determined, if Vref is set to the voltage of Vth+VBE, and logic control device can be coupled to I<2>L element. |
