Abstract: A stacked switching circuit with normally-on devices includes a first normally-on switch coupled between a first input rail and an output port, and is coupled to be switched in response to a first control signal. A second normally-on switch is coupled to the output port and is coupled to a normally-off switch in a cascode coupled configuration. A second terminal of the normally-off switch is coupled to a second input rail. The normally-off switch is coupled to be switched in response to a second control signal. Switching of the stacked switching circuit is coupled to provide chopped high frequency pulses through the output port. Current flow through the stacked switching circuit between the first input rail and the second input rail is blocked at startup.

Abstract: A stacked switching circuit with normally-on devices includes a first normally-on switch coupled between a first input rail and an output port, and is coupled to be switched in response to a first control signal. A second normally-on switch is coupled to the output port and is coupled to a normally-off switch in a cascode coupled configuration. A second terminal of the normally-off switch is coupled to a second input rail. The normally-off switch is coupled to be switched in response to a second control signal. Switching of the stacked switching circuit is coupled to provide chopped high frequency pulses through the output port. Current flow through the stacked switching circuit between the first input rail and the second input rail is blocked at startup.

Abstract: A power bus monitor for use in an electronic product is coupled to receive power from an external power supply. The power bus monitor includes a signal detector coupled to an output of the external power supply to receive and demodulate information encoded on the output of the external power supply into a sequence of bits. A decoder is coupled to receive the sequence of bits from the signal detector and decrypt the sequence of bits. A logical comparator is coupled to receive the sequence of bits decrypted by the decoder. The logical comparator is coupled to assert an authentication signal indicating the external power supply is authorized to provide power to the electronic product when the logical comparator recognizes the sequence of bits decrypted by the decoder as a key.

Abstract: A power bus monitor for use in an electronic product is coupled to receive power from an external power supply. The power bus monitor includes a signal detector coupled to an output of the external power supply to receive and demodulate information encoded on the output of the external power supply into a sequence of bits. A decoder is coupled to receive the sequence of bits from the signal detector and decrypt the sequence of bits. A logical comparator is coupled to receive the sequence of bits decrypted by the decoder. The logical comparator is coupled to assert an authentication signal indicating the external power supply is authorized to provide power to the electronic product when the logical comparator recognizes the sequence of bits decrypted by the decoder as a key.

Abstract: A power supply that can be authenticated is disclosed. An apparatus according to aspects of the present invention includes an external power supply of an electronic product that modulates an output of the power supply with information encoded to identify the power supply to the product.

Abstract: A videoconferencing system uses a modular terminal that includes a conventional video camera or digital still camera coupled to the input port of the videocommunicator, such as a set top box. The camera includes a video input port and a display screen, and the videocommunicator is coupled to the video input port of the camera, whereby videoconference images are displayed on the camera display screen.