Usb isolator with advanced control features

A multi-modal voltage regulator system, comprising:

• a voltage regulator, selectively enabled and disabled in response to a control input,
• a pair of voltage monitors,
• a first voltage monitor coupled to a first voltage source at a first input and a first threshold voltage at a second input, the first voltage source operable at a pair of voltages, one voltage higher than the second voltage,
• a second voltage monitor coupled to a second voltage source at a first input thereof and a second threshold voltage at a second input, the second voltage source operable at the second voltage or operable to be driven by an output of the voltage regulator,
• control logic, having a pair of inputs each coupled to an output of a respective voltage monitor, and having an output coupled to the control input of the voltage regulator.

An isolator system, comprising

• a plurality of isolation devices bridging an isolation barrier between an upstream circuit sub-system and a downstream circuit sub-system,
• each of the upstream circuit sub-system and the downstream circuit sub-system comprising:
• a USB transceiver having a USB transmitter for outputting USB signals from the isolation system and a USB receiver for receiving USB signal input to the isolation system,
• an isolator transceiver having a transmitter for outputting isolation signals to the plurality of isolation devices and a receiver for receiving isolation signals from the plurality of isolation devices, and
• a sub-system controller to govern operational states of the respective sub-system based on signals received from the respective sub-system's USB transceiver and from the isolator transceiver.

An isolator device, comprising

• a plurality of isolation devices bridging an isolation barrier between an upstream circuit sub-system and a downstream circuit sub-system,
• each of the upstream circuit sub-system and the downstream circuit sub-system comprising:
• a USB transceiver for exchanging USB signals with respective external components, and
• an isolator transceiver coupled to the respective USB transceiver to exchange signals between the USB transceiver and the isolation devices;
• wherein, for at least one circuit sub-system, the isolator transceiver transmitter includes a pulse generator and a refresh pulse generator to generate pulses in response to an input logic signal and to repeat the generated pulses according to a refresh interval, and
• wherein, for at least the other circuit sub-system, the isolator transceiver receiver includes a watchdog timer to maintain the receiver in a reception state if pulses are received within a watchdog interval.