Patent ID: 8847244
Filing Date: 2014-09-30
Classification: H01L,H03K,H04B

Abstract:
1. A photocoupler configured to convert an input electrical signal into an optical signal, convert the optical signal into an output electrical signal, and supply the output electrical signal to an external load, the photocoupler comprising: a light emitting element configured to convert the input electrical signal into the optical signal; a first photodiode array configured to generate a first photovoltaic power by the optical signal being incident on the first photodiode array; a second photodiode array configured to generate a second photovoltaic power by the optical signal being incident on the second photodiode array; a third photodiode array configured to generate a third photovoltaic power by the optical signal being incident on the third photodiode array; an enhancement-mode MOSFET configured such that the first photovoltaic power is supplied to a gate of the enhancement-mode MOSFET; a first depletion-mode MOSFET configured such that the second photovoltaic power is supplied to a gate of the first depletion-mode MOSFET; and a second depletion-mode MOSFET configured such that the third photovoltaic power is supplied to a gate of the second depletion-mode MOSFET; a drain current of the enhancement-mode MOSFET being supplied to the external load when the optical signal is ON, a drain current of the first depletion-mode MOSFET being supplied to the external load when the optical signal is OFF and a voltage passing through the second depletion-mode MOSFET switched to the ON state is supplied to the gate of the first depletion-mode MOSFET, and the drain current of the first depletion-mode MOSFET being larger than a drain current of the first depletion-mode MOSFET when a gate voltage of the first depletion-mode MOSFET is zero.