| 摘要 |
<p>PURPOSE:To set optionally positive and negative threshold voltages by inserting a constant current source between a common potential and a collector of a resistor (TR) connected to a power potential in TRs of emitter coupling. CONSTITUTION:A base of a TR Q14 and a base of a TR Q16 are connected to a constant current source power terminal 13. When an input terminal 11 is at an L level, an output terminal 12 goes to an L level. In this case, a current I1 by a constant current source comprising a TR Q16 and a resistor R16 flows to a resistor R11. When an input voltage level at an input terminal 11 rises and exceeds a prositive threshold voltage V<+>T, the level of an output terminal 14 goes to an H level. Let a collector current of a TR Q11 in this case be I2, a current I2+I2 flows to the resistor R11. Then the positive threshold voltage V<+>T is set by the resistor R11 and the current I1 and a negative threshold voltage V<->T is set by the resistor R11 and the currents I1, I2 optionally.</p> |
