Current Mirror Output Stage Reconfiguration for Regulator Stability

The patent implements dynamic reconfiguration of the output stage by switching between different operational modes (first operational mode with larger output device for high current, second operational mode with smaller effective output device for low current) based on detected output current levels. This dynamic adaptation allows the circuit to maintain optimal output impedance across varying load conditions, improving stability without incurring continuous power losses associated with oversized devices operating at low current.

The patent changes the effective parameters of the output stage by altering which devices are active in the current mirror configuration. A detector circuit monitors output current and controls switches that reconfigure the current mirror ratio, effectively changing the output device's electrical characteristics (output impedance) to match the load requirements, thereby maintaining stability across the full operating range without permanent size reduction.

The patent makes the existing power output device perform multiple functions: it serves as the primary current mirror output device during normal operation and simultaneously acts as the minimum load during low-load conditions through reconfiguration. The same device structure is dynamically repurposed rather than adding separate dedicated components, reducing overall device complexity while maintaining stability.

The output stage reconfigures itself based on detected current levels to provide the necessary minimum load condition. The system uses its own internal resources (the power output device itself) to satisfy the stability requirement rather than relying on external parallel resistive loads, thereby reducing device complexity and eliminating unnecessary power dissipation in dedicated load resistors.

The patent dynamically adjusts the current mirror ratio based on output current detection. At high output currents, a higher current mirror ratio is used for efficiency. At low output currents, the ratio is reduced to maintain stability. This dynamic adjustment is achieved through switches that reconfigure which mirror devices are active, allowing the system to optimize both efficiency and stability at different operating points rather than being locked into a fixed ratio.

The patent changes the operational parameters of the current mirror by selectively activating different devices in the mirror network. The effective current mirror ratio becomes a variable parameter that adapts to load conditions, controlled by a detector circuit that monitors output current and switches between configuration states, thereby optimizing the balance between stability and power efficiency.