Regulator Circuit Undershoot Suppression via Detection Capacitor

The patent divides the gate control into two independent paths: a main control path through the error amplifier for steady-state operation, and a rapid response path through the detection transistor and capacitor for transient response. This segmentation allows the large transistor to maintain current capacity while the separate rapid response path compensates for the gate capacitance delay, resolving the contradiction between current capacity and response speed.

The patent implements dynamic bias current control where the error amplifier's bias current is adjusted according to the operating state. During transient conditions, the detection transistor activates to provide rapid response through the capacitor path. During stable operation, the system maintains lower bias current to reduce power consumption, achieving adaptive response speed that matches actual needs without continuous high power consumption.

The patent introduces a detection transistor and capacitor as intermediary elements between the output transistor and the control circuit. This intermediary path can rapidly charge/discharge the capacitor to quickly adjust the gate voltage in response to load changes, providing fast response without requiring high bias current in the error amplifier, thus maintaining low power consumption while improving response speed during transients.

The detection transistor and capacitor are configured to anticipate and respond to load changes before they cause significant output voltage deviation. The circuit monitors the output current and preemptively adjusts the gate voltage through the capacitor path, compensating for the inherent delay in large transistors. This preliminary action prevents output voltage overshoot or undershoot, maintaining stability despite the large transistor size.