Dual-Timer DC-DC Converter Control Beyond Minimum On-Off Time Limits
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Solution Overview
Problem
Conventional DC-DC converter systems have limited operational ranges due to minimum on-time and off-time constraints, restricting the duty cycle and output-to-input voltage ratio, which hampers their efficiency and adaptability.
Innovation Solution
The proposed DC-DC converter system incorporates a controller with timers and logic circuitry that dynamically adjusts the on and off durations of the switch based on target switching frequencies and input/output voltages, extending the off-time and on-duty cycle ranges by generating an expiration signal upon expiration of predetermined durations, thereby enhancing the voltage ratio and duty cycle flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional fixed frequency or adaptive on-time/off-time control is used, then the switching frequency can be maintained, but the duty cycle range is limited due to minimum on-time and off-time constraints
Solution Approach 1:
The controller is segmented into multiple independent timer units (first timer for off-time, second timer for on-time) that can be selectively activated. This segmentation allows the system to achieve extended duty cycle range without requiring a complete redesign of the controller structure, as each timer handles specific timing functions independently.
Solution Approach 2:
The system dynamically switches between different timer configurations based on operating conditions. The controller can activate either the first timer for off-time control or the second timer for on-time control, creating a dynamic adaptation mechanism that extends the duty cycle range while maintaining manageable controller complexity through conditional activation.
2Adaptability or versatility
If minimum on-time and off-time constraints are enforced, then reliable switching operation is ensured, but the output-to-input voltage ratio range is restricted
Solution Approach 1:
The system changes the timing parameters dynamically by switching between different timer configurations. When the first timer is activated, it extends the off-time; when the second timer is activated, it extends the on-time. This parameter change approach allows the voltage ratio range to be extended while maintaining reliable switching operation through controlled timing adjustments.
Solution Approach 2:
The controller preliminarily determines which timer configuration is needed based on the desired voltage ratio before actual switching occurs. By pre-configuring the appropriate timer (first or second) based on operating conditions, the system ensures that timing constraints are met before switching begins, maintaining reliability while achieving the desired voltage conversion ratio.
3Adaptability or versatility
If dual timer configuration is implemented, then the duty cycle and voltage ratio ranges are extended, but the controller complexity increases
Solution Approach 1:
Both timer units are designed with identical functional capabilities but different timing parameters. The first timer handles off-time control while the second timer handles on-time control, creating a universal timing mechanism that can adapt to different operational requirements. This multi-functionality allows a single controller architecture to support extended operational ranges without proportionally increasing complexity.
4Productivity
If selective timer activation is used, then efficiency is improved by avoiding unnecessary switching, but control logic complexity increases
Solution Approach 1:
The control logic dynamically selects which timer to activate based on real-time operating conditions and desired voltage ratios. This dynamic selection mechanism improves efficiency by activating only the necessary timer for each operating mode, avoiding unnecessary switching operations. The conditional activation logic, while adding some complexity, enables significant efficiency gains through optimized switching behavior.
Data Source
AI summary
A converter system includes a first switch and a controller configured to switch the first switch between first and second states based on input and output voltages of the converter system, wherein the controller includes: a timer unit including a first timer configured to determine a first duration based on a target switching frequency of the converter system, and a second timer configured to determine a second duration based on a predetermined duration equal to or greater than a minimum duration of the first state of the first switch and the input and output voltages; and a control logic unit, configured to switch the first switch from the second state to the first state upon expiration of both the first and second durations.