Signal transmission circuit having a latch-up function
AssigneeKabushiki Kaisha Toshiba
InventorHironobu Miyasaka
Life of this patent
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Abstract
A signal transmission circuit having a latch-up function has a first and a second photo-couplers, each of which has a photo-diode (light emitting diode) and a photo-transistor. The photo-diode in the first photo-coupler is series-connected with the photo-transistor in the second photo-coupler between high and low voltage supplies. The other photo-diode and photo-transistor in said first and second photo-couplers are connected in the same way. As a result, signals are transmitted between those two photo-couplers with a high noise resistance.
Claims11
A signal transmission circuit, comprising:
- first light emitting means;
- first light receiving means which is triggered to conduct by a light emitted from said first light emitting means;
- second light emitting means which is series-connected with said first light receiving means between a high voltage supply and a low voltage supply;
- second light receiving means which are triggered to conduct by a light emitted from said second light emitting means, and which are series-connected with said first light emitting means between said high voltage supply and said low voltage supply;
- a load which is inserted between said first light emitting means and said high voltage supply;
- a signal input terminal which is provided at the connecting point between said first light receiving means and said second light emitting means;
- and
- a signal output terminal which is provided at the connecting point between said first light emitting means and said second light receiving means.
A signal transmission circuit, comprising:
- two light emitting diodes parallel connected with each other in the reverse direction;
- a photo-transistor which is triggered to conduct by a light emitted from either one of said two light emitting diodes,
- a third light emitting diode which is series-connected with said photo-transistor between a high voltage supply and a low voltage supply;
- at least one photo-MOSFET which is triggered to conduct by a light emitted from said third light emitting diode, and which is series-connected with said parallel-connected light emitting diodes between said high voltage supply and said low voltage supply;
- a load which is inserted between said parallel-connected light emitting diodes and said high voltage supply;
- a signal input terminal which is provided at the connecting point between said photo-transistor and said third light emitting diode;
- and
- a signal output terminal which is provided at the connecting point between said parallel-connected light emitting diodes and said photo-MOSFET.
Dependencies are inferred from the claim text.