Hysteretic Regulator Delay Compensation for Output Voltage Overshoot
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hysteretic switching regulators face challenges in maintaining accurate and stable output voltage due to overshoot errors caused by duty cycle variations and inductor current changes, which existing methods fail to adequately correct.
Innovation Solution
A delay compensation circuit is introduced that adds an input-voltage-dependent delay to the hysteretic comparator's output, specifically adjusting the delay on the rising or falling edges to balance inductor current slopes and correct overshoot errors, applicable to both voltage-mode and current-mode regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If hysteretic control is used to maintain output voltage within a hysteresis band, then the output voltage stability is improved, but overshoot errors occur due to duty cycle variations and inductor current changes
Solution Approach 1:
The patent applies preliminary action by adding a delay to the comparator output signal before it reaches the switch control. This delay is calculated based on expected overshoot conditions and is applied in advance to counteract the overshoot error. The delay compensation circuit introduces a time delay proportional to the hysteresis band and inversely proportional to the inductor current slope, which pre-adjusts the switching timing to compensate for anticipated voltage overshoot, thereby improving output voltage accuracy while maintaining stability.
2Manufacturing precision
If error amplifiers and compensation networks are added to correct output errors, then the output voltage accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent extracts and eliminates the need for separate error amplifiers and compensation networks by integrating the overshoot correction function directly into the hysteretic control loop. The delay compensation circuit achieves output voltage accuracy correction without requiring additional error amplification stages or external compensation components, thereby improving output voltage accuracy while avoiding increased device complexity.
Solution Approach 2:
The patent applies self-service by making the hysteretic control system self-correcting through the delay compensation mechanism. The system uses its own internal signals (comparator output, inductor current) to generate the compensating delay, eliminating the need for external error amplifiers or compensation networks. The control system serves its own correction needs through the integrated delay compensation circuit, maintaining simplicity while achieving accurate output voltage regulation.
Data Source
AI summary
A hysteretic regulator is provided. The hysteretic regulator includes a delay compensation circuit that adds a delay to the output of the hysteretic comparator. The delay is dependent on the input voltage. For low duty cycles, the slope of the inductor current is much greater for the rising edge than it is for the falling edge. The delay compensation circuit adds sufficient delay to the falling edge so that the undershoot cancels the overshoot.