Patent ID: 6178514
Filing Date: 2001-01-23
Classification: G06F

Abstract:
An apparatus for interfacing a bus to a device, the bus including a power line carrying power and a signal line carrying a signal, the device including a power input and a signal input, the interface apparatus including:a. a power output connected to the device power input;b. a power input connected to the bus power line;c. a signal input connected to the bus signal line;d. a signal output connected to the device signal input;e. an energy storage device having an input and an output, the energy storage device output connected to the interface apparatus power output;f. a power converter having a power input connected to the interface apparatus power input and a power output connected to the energy storage device input, whereby the power converter receives power from the bus power line and converts it to a form suitable for charging the energy storage device, the power converter further including:a current sensor being connected in series with the power converter power input and output and having an output carrying a signal representative of the current flowing through the current sensor; anda current limiter having a predetermined current limit, being operably connected to the power converter power input and power output, and having an input connected to the current sensor output for receiving the current sensor signal representative of the current flowing through the current sensor, whereby the current limiter limits the current drawn by the device and the interface apparatus to the predetermined current limit; andg. a signal conditioner having a first input connected to the energy storage device output, a second input connected to the interface apparatus signal input, the signal conditioner including a transfer function that produces a signal conditioner output signal at the signal conditioner output that is a function of the level of energy in the energy storage device and the level of energy of the bus signal or the signal conditioner output signal.