Power Supply Controller Transient Response via Variable Frequency Reference
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Solution Overview
Problem
Existing PWM power supply controllers exhibit poor transient response due to limited response time, leading to variations in output voltage and restricted current supply during transient events.
Innovation Solution
A power supply controller is configured to utilize a plurality of variable reference signals with different frequencies, allowing the selection of a higher frequency during transient events to enhance response time, comprising a variable reference generator section, a selector, a PWM control section, and an error amplifier to adjust the switching signal based on feedback signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single frequency reference signal is used in PWM power supply controllers, then the device complexity is reduced, but the transient response performance deteriorates
Solution Approach 1:
The reference signal generation is segmented into multiple independent oscillators operating at different frequencies. Each oscillator generates a reference signal at a specific frequency, and these segmented signals are then combined through a selector circuit. This segmentation allows the system to switch between different frequency ranges (e.g., 650 kHz to 1 MHz) depending on transient conditions, improving transient response without requiring complete redesign of the reference generation system.
Solution Approach 2:
The reference signal frequency is made dynamic rather than fixed. The system automatically adjusts the reference frequency based on transient detection - using higher frequencies (1 MHz) during transient events and lower frequencies (650 kHz) during steady-state operation. This dynamic adaptation resolves the contradiction by allowing the system to optimize for transient response when needed while maintaining simpler operation during normal conditions.
2Speed
If the response time is increased to improve transient response, then the current supply capability during transient is improved, but the output voltage stability deteriorates due to variations
Solution Approach 1:
The system changes the frequency parameter of the reference signal based on operating conditions. During transients, the frequency is increased to 1 MHz to improve response time and current supply capability. During steady-state operation, the frequency is reduced to 650 kHz to minimize output voltage variations and maintain stability. This parameter change allows optimization of both response speed and voltage stability for different operational phases.
Solution Approach 2:
The system uses feedback mechanisms to detect transient conditions and automatically adjusts the reference frequency accordingly. The feedback loop monitors the operating state and triggers frequency switching when transients are detected, ensuring that the response time is improved only when actually needed, thereby maintaining output voltage stability during normal operation while enabling fast response during transients.
3Reliability
If a higher frequency reference signal is used continuously, then the transient response is improved, but the energy consumption increases
Solution Approach 1:
Instead of continuous high-frequency operation, the system employs periodic switching between frequency modes. The high frequency (1 MHz) is activated only periodically when transients are detected, while the lower frequency (650 kHz) is used during normal steady-state periods. This periodic action pattern ensures that energy-intensive high-frequency operation occurs only when necessary for transient response, significantly reducing overall energy consumption while maintaining reliable transient performance.
Data Source
AI summary
In one embodiment, a power supply controller utilizes a plurality of reference signals that operate at different frequencies to form a switching signal that is suitable to control a power device to regulate an output voltage.