Fast transient precision power regulation apparatus

An electronic current-limiting apparatus, comprising:

• a pass transistor to receive a voltage regulation control input signal on a voltage regulation control input path at a gate terminal and to allow a magnitude of current flow through a current channel associated with the pass transistor, the current flow based on a magnitude of the voltage regulation control input signal;
• a fast transient feedback circuit communicatively coupled to the voltage regulation control input path to receive the voltage regulation control input signal, to sense a first over-current condition, and to decrease the magnitude of the voltage regulation control input signal in response to sensing the first over-current condition;
• a precision feedback circuit communicatively coupled to the voltage regulation control input path to receive the voltage regulation control input signal, to sense a second over-current condition, and to decrease the magnitude of the voltage regulation control input signal in response to sensing the second over-current condition, the precision feedback circuit to more accurately control the second over-current condition than control provided by the fast transient feedback circuit for the first over-current condition by compensating for at least one component characteristic mismatch between the pass transistor and a current sense transistor in the precision feedback circuit, wherein the precision feedback circuit includes:
• a precision current sense transistor communicatively coupled to the voltage regulation control input path to receive the voltage regulation control input signal to generate a precision feedback current sense signal proportional to the magnitude of current flow through the pass transistor;
• an operational transconductance amplifier (OTA) with a first input communicatively coupled to an output of the precision current sense transistor and a second input communicatively coupled to a voltage regulation output path to generate a precision feedback sense current;
• a characteristic matching feedback transistor communicatively coupled between an output of the OTA and the first input to cause a signal at the first input to track a regulator output voltage and to thereby compensate for at least one component characteristic mismatch between the pass transistor and the precision current sense transistor;
• a reference current source to generate a reference current;
• and
• a precision loop transistor gate-coupled to the output of the OTA and channel-coupled between a voltage rail and the reference current source to receive the precision feedback sense current at the gate of the precision loop transistor and to generate an attenuated sense current for comparison to the reference current.

A current-limited voltage regulator, comprising:

• a pass element to receive a voltage regulation control input signal on a voltage regulation control input path and to allow a magnitude of current flow through the pass element, the magnitude of current flow being based on a magnitude of the voltage regulation control input signal;
• a fast transient feedback circuit communicatively coupled to the voltage regulation control input path to receive the voltage regulation control input signal and to decrease the magnitude of the voltage regulation control input signal in a first over-current condition;
• a precision feedback circuit communicatively coupled to the voltage regulation control input path to receive the voltage regulation control input signal, to sense a second over-current condition, and to decrease the magnitude of the voltage regulation control input signal in the second over-current condition, the precision feedback circuit to more accurately control the second over-current condition than control provided by the fast transient feedback circuit for the first over-current condition by correcting for a component characteristic mismatch between the pass element and a current sense element of the precision feedback circuit, the precision feedback circuit further including a reference current source;
• a voltage divider communicatively coupled between an output of the voltage regulator and a voltage rail to provide a voltage sense signal;
• and
• a voltage regulation error amplifier communicatively coupled to the voltage divider to receive the voltage sense signal, to compare the voltage sense signal to a reference voltage input, and to generate the voltage regulation control input signal.