Research on Dynamic Response Optimization of Linear Regulators Based on Predictive Compensation

The issue of output voltage fluctuations in Low Dropout Regulators (LDOs) under high-frequency dynamic loads severely restricts their application in precision systems such as fiber optic gyroscopes. Traditional compensation techniques exhibit significant limitations in effectively suppressing ripple noise caused by high-frequency load transients due to the lag in feedback loops. For example, fiber optic gyroscopes require maintaining output voltage fluctuations below 1 mV within a 10 MHz bandwidth, whereas traditional compensation methods typically yield measured values ranging from 10 to 100 mV. This paper proposes a dynamic response optimization method for LDOs based on predictive compensation. By establishing a load current time-series prediction model and integrating a feedforward control strategy, a compensation voltage Vcomp is generated prior to load transients to directly adjust the gate state of the power transistor, enabling predictive compensation for dynamic load changes. LTspice simulation results demonstrate that the proposed scheme reduces the output ripple amplitude caused by a dynamic load (0.2 A step current with a 30 ns edge time) from 7.2 mV to 0.36 mV, achieving a reduction of 26 dB. Experimental verification shows that under a 5V output voltage and an actual dynamic load (50 Ω step), the peak-to-peak ripple is significantly reduced from 10.64 mV to 2.64 mV (a decrease of approximately 12 dB). The stability of the output voltage is notably improved, with the undershoot settling time shortened from 2.5 μs to within 300 ns and the overshoot settling time optimized from 7 μs to below 500 ns. Theoretical analysis indicates that as the matching accuracy of the compensation voltage increases, the system’s steady-state time can further approach zero. This study provides a new approach for the design of high-performance LDOs, particularly suitable for power noise suppression in high-speed data converters and precision sensing systems.