Correction Circuit for Switched Power Supply Transient Response
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Solution Overview
Problem
Existing switched power supply control systems face challenges in providing a fast enough transient response to maintain output voltage within a narrow window during load transients, often requiring additional components or complexity and still experiencing delays in inductive storage element response.
Innovation Solution
A correction circuit that compares inductor current to load current and provides a computed correction value to rapidly adjust the duty cycle of pulse width modulation, using multipliers and dividers to ensure inductor current matches load current, which can be implemented in either analog or digital circuitry and used with feedback or feed forward control systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If feedback control is used to control output voltage, then output voltage stability is improved, but transient response speed deteriorates due to fixed relationships between operating frequencies and control loop crossover frequencies
Solution Approach 1:
The patent applies preliminary action by measuring the difference between inductor current and output current before the transient response issue fully manifests, and using this measurement to proactively adjust the duty factor through a correction parameter. This allows the system to anticipate and correct transient response issues before they degrade output voltage stability, rather than reacting after the problem occurs.
2Speed
If operating frequency is raised and inductor value is lowered to improve transient response, then transient response speed is improved, but device complexity and component requirements worsen
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the duty factor parameter based on the measured current difference and a computed correction parameter. Instead of changing physical components like inductor values or operating frequencies, the system modifies the control parameter (duty factor) to achieve improved transient response while maintaining the same hardware configuration.
3Stability of the object's composition
If additional components like capacitors or load lines are added to improve transient response, then output voltage control is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies self-service by using the power supply's existing components (inductor, output capacitor, current sensing circuitry) to generate the correction parameter. The inductor current measurement and output current measurement are combined to create a correction signal that adjusts the duty factor, allowing the system to self-correct transient response issues without requiring external assistance from additional components.
4Speed
If feed forward control is used to quickly adjust duty factor, then initial response speed is improved, but inductor current adjustment delay persists due to RL time constant
Solution Approach 1:
The patent applies feedback by continuously measuring the difference between inductor current and output current, and using this feedback information to compute a correction parameter that adjusts the duty factor. This closed-loop approach ensures that the inductor current is actively driven to match the output current, overcoming the natural RL time constant delay through continuous correction based on actual current measurements.
Data Source
AI summary
A correction circuit for use in a switched power supply wherein the correction circuit provides a correction signal indicating a duty cycle adjustment necessary to modify pulse width modulation of the power supply such that the output inductor current matches the load current drawn by a load connected to the power supply. The correction circuit may be used in conjunction with feed forward and/or feed back control circuits. The correction circuit may be implemented using either digital or analog circuit components.