Patent ID: 8692586

Claim:
An output circuit for generating an optically isolated output signal for an external device having an external power source, the output circuit comprising: a first opto-coupler including a first light emitting device coupleable to a first power source, the first opto-coupler including a first input and a first transistor switch optically isolated from the first input; a second opto-coupler including a second light emitting device coupleable to the first power source, the second opto-coupler including a second input and a second transistor switch optically isolated from the second input; a first charge storage device providing a first capacitance, the first charge storage device being chargeable in response to activation of the first transistor switch and dischargeable in response to activation of the second transistor switch; a second charge storage device that is coupleable to and chargeable from the external power source; and an output transistor disposed between a first output rail and a second output rail of the external power source and coupled to the first charge storage device; wherein the output circuit is configured and operative upon pulse activation of the first input by a first pulse to turn on the first transistor switch to charge the first charge storage device and to cause the output transistor to assume a first output state and wherein the output circuit is configured and operative upon pulse activation of the second input to turn on the second transistor switch to discharge the first charge storage device and to cause the output transistor to assume a second output state distinct from the first output state, and wherein the first charge storage device is chargeable from the second charge storage device in response to pulse activation of the first input.