Abstract: A protection circuit that is provided inside a semiconductor package to protect a first transistor including a first collector connected to a terminal of the semiconductor package, a first emitter, and a first base. The protection circuit includes a second transistor that includes a second collector connected to the terminal, a grounded second emitter, and a second base; and a third transistor that includes a third collector connected to the terminal, a third emitter connected to the second base, and a third base. A breakdown voltage between the third collector and the third base is lower than a breakdown voltage between the first collector and the first base.

Abstract: An optical coupling device includes a first receiving chip having a first region on one end and a second region on another end side. A first emitting chip is disposed on the first region. A second receiving chip has a third region on one end and a fourth region on another end. A second emitting chip is disposed on the fourth region. The first and third regions are adjacent, and the second and fourth regions are adjacent. A first connection portion is disposed on the second region and is electrically connected to the second light emitting chip through a bonding wire. A second connection portion is disposed in the third region and is electrically connected to the first light emitting chip through a bonding wire.

Abstract: An optical coupling device includes a first receiving chip having a first region on one end and a second region on another end side. A first emitting chip is disposed on the first region. A second receiving chip has a third region on one end and a fourth region on another end. A second emitting chip is disposed on the fourth region. The first and third regions are adjacent, and the second and fourth regions are adjacent. A first connection portion is disposed on the second region and is electrically connected to the second light emitting chip through a bonding wire. A second connection portion is disposed in the third region and is electrically connected to the first light emitting chip through a bonding wire.

Abstract: A light receiving circuit includes a light receiving element, a transimpedance amplifier, a delay circuit and a comparator. The transimpedance amplifier is configured to convert the current signal into a first voltage. The comparator includes first to third current control elements each including first to third electrodes and configured to control current of the third electrode by voltage of the second electrode. The first voltage is inputted to the second electrode of the first current control element. Output voltage of the delay circuit is inputted to the second electrode of the second current control element. A second voltage is inputted to the second electrode of the third current control element. The comparator is configured to compare output current of the first current control element with sum of output current of the second current control element and output current of the third current control element.

Abstract: A light receiving circuit includes a light receiving element, a transimpedance amplifier, a delay circuit and a comparator. The transimpedance amplifier is configured to convert the current signal into a first voltage. The comparator includes first to third current control elements each including first to third electrodes and configured to control current of the third electrode by voltage of the second electrode. The first voltage is inputted to the second electrode of the first current control element. Output voltage of the delay circuit is inputted to the second electrode of the second current control element. A second voltage is inputted to the second electrode of the third current control element. The comparator is configured to compare output current of the first current control element with sum of output current of the second current control element and output current of the third current control element.

Abstract: According to one embodiment, a receiving circuit is provided. The receiving circuit has a first light receiving element, a signal voltage generator, a second light receiving element, a delay element and a comparator. The first light receiving element receives a light signal and converts the light signal into a first current. The signal voltage generator converts the first current into a signal voltage. The second light receiving element receives the light signal and converts the light signal into a second current. The reference voltage generator converts the second current into a voltage and outputs the voltage as a reference voltage. The delay element delays and reduces a signal component of the reference voltage. The comparator compares the signal voltage from the signal voltage generator with a threshold voltage based on an output voltage of the delay element.

Abstract: According to one embodiment, a receiving circuit is provided. The receiving circuit has a first light receiving element, a signal voltage generator, a second light receiving element, a delay element and a comparator. The first light receiving element receives a light signal and converts the light signal into a first current. The signal voltage generator converts the first current into a signal voltage. The second light receiving element receives the light signal and converts the light signal into a second current. The reference voltage generator converts the second current into a voltage and outputs the voltage as a reference voltage. The delay element delays and reduces a signal component of the reference voltage. The comparator compares the signal voltage from the signal voltage generator with a threshold voltage based on an output voltage of the delay element.