| 摘要 |
PURPOSE:To facilitate the titled circuit made into IC providing the 1st 3rd switching elements for turn-on drive, short-circuit and current drawing of a thyristor so as to the scale and current consumption of an on/off drive circuit for the thyristor. CONSTITUTION:In turning on the thyristor of a cahnnel, an on-drive switching element S1x of the said channel is turned on and a gate-cathode short-circuit element S2x is turned off to supply an on-drive current is supplied to the gate from an on=drive power supply VD via the element S1 to turn on a thyristor SCRx. Since the drive current does not flow except through the gate, even if the current is very small, the thyristor is turned on. On the other hand, in a channel of the off-holding state, the element S1x is turned off and the element S2x is turned on, then since no current supply comes from the power supply VD and the gate-cathode is short-circuited, the thyristor keeps the off-state. In turning on the gate current drawing switching element SOFF next, each gate is biased to a low potential to draw the current and all the thyristors are turned off. |
