| 摘要 |
<p>PURPOSE:To improve the response speed of thyristor switch holding current supply, by controlling a plurality of constant current circuits, through the use of storage elements storing the state of connection of subscriber circuits. CONSTITUTION:If no subscriber circuit is connected, an OFF pulse is given, a storage element 200 stores the state, outputs QA, QB, QC are all at 1, constant current circuits 201, 202, 203 are at all off-state, a transistor 205 turns on, a thyristor switch is reverse-biased and turns off. When the 1st subscriber circuit is connected, an ON-pulse is given, only the output QA is 0, only the constant current circuit 201 turns on, the thyristor switch is conductive and a holding current is supplied. When the 2nd subscriber circuit is connected, the ON-pulse is again given and the output QB is also 0, the constant current circuit 202 turns on and the thyristor switch holding current for two subscriber circuits can be supplied.</p> |
