Voltage Regulator Source-Ground Compensation for Fast Load Response
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Solution Overview
Problem
Conventional voltage regulators experience delays in responding to sudden changes in load current due to delay compensation using a Miller capacitor, which affects the stability and responsiveness of the output voltage.
Innovation Solution
The voltage regulator incorporates a phase advance compensation circuit with a resistor and capacitor in the source ground amplification circuit, along with an offset generation element, to reduce impedance and gain, allowing for quicker response to load current changes by eliminating the need for delay compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If delay compensation using a Miller capacitor is used for phase compensation, then phase stability is improved, but response speed to sudden load current changes deteriorates
Solution Approach 1:
The patent changes the compensation mechanism from delay compensation (Miller capacitor) to phase advance compensation. By introducing a phase advance compensation circuit with resistor and capacitor that generates a leading phase signal, the system achieves both phase stability and fast response. The parameter change involves switching from lagging phase compensation to leading phase compensation, fundamentally altering the compensation characteristic.
Solution Approach 2:
The phase advance compensation circuit performs preliminary action by generating a compensation signal that leads the phase before the load current change occurs. The capacitor in the phase advance compensation circuit charges in advance, and when load current changes suddenly, the pre-charged capacitor provides immediate compensation current, eliminating the response delay associated with Miller capacitor discharge.
2Speed
If phase advance compensation circuit is introduced, then response speed is improved, but circuit complexity increases
Solution Approach 1:
The patent merges the phase advance compensation function with the existing error amplification circuit and source ground amplification circuit. The phase advance compensation circuit is integrated into the feedback path, sharing components and signal paths with existing circuits. This merging approach achieves phase advance compensation without adding completely separate compensation circuits, thereby limiting the increase in overall circuit complexity.
Data Source
AI summary
The voltage regulator includes: an error amplification circuit, outputting a signal amplifying a difference between a reference voltage and a feedback voltage; a source ground amplification circuit, amplifying the signal supplied from the error amplification circuit and outputting the signal as a control signal; and an output transistor, including a gate to which the control signal is supplied and outputting an output voltage. The source ground amplification circuit includes: a phase advance compensation circuit, containing a resistor and a capacitor; a load, containing a resistor and an offset generation element generating an offset voltage; and a transistor, containing: a gate receiving the signal output from the error amplification circuit; a source being connected with a first end of the resistor and a first end of the capacitor, the resistor and the capacitor being contained in the phase advance compensation circuit; and a drain connected with the load.