Multimode SMPS Control With High-Resolution PWM and Slope Generation
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Solution Overview
Problem
Existing SMPS converters face challenges in switching between operating modes while maintaining high resolution control signals, particularly in low load conditions, due to the need for costly hardware and complex software interactions, and lack of efficient slope generation capabilities without external components or high-cost PLLs.
Innovation Solution
A controller circuit with multiple signal sources and a selecting circuit that allows dynamic switching between signal sets, coupled with a high resolution signal forwarding circuit for generating precise PWM signals, and a digital ramp generation circuit using bit inversion and pulse swallowing techniques to produce high resolution slope signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a complete software control is used to reconfigure the control loop for different operation modes, then the adaptability between different operation modes is improved, but the device complexity and computing power requirements increase
Solution Approach 1:
The patent implements dynamic switching between different operation modes (CCM, DCM, CRM) through a multimode controller that can reconfigure the control loop in real-time. The controller dynamically adjusts the PWM generation parameters and control loop characteristics based on operating conditions, enabling seamless transition between continuous conduction mode, discontinuous conduction mode, and critical conduction mode without requiring complete hardware reconfiguration.
Solution Approach 2:
The patent employs a universal control architecture that can handle multiple operation modes using the same hardware resources. The multimode controller integrates functionality for both peak current control and time-fixed control within a single control loop, allowing the system to operate in CCM, DCM, or CRM depending on load and input voltage conditions without requiring separate dedicated control circuits for each mode.
2Reliability
If hardware resources are doubled to provide separate control loops for different operation modes, then the reliability of mode-specific control is improved, but the device complexity and cost increase
Solution Approach 1:
The patent implements a universal control architecture where a single multimode controller handles multiple operation modes (CCM, DCM, CRM) with different control strategies. The controller dynamically reconfigures the same hardware resources to provide mode-appropriate control characteristics, eliminating the need for separate dedicated control loops while maintaining reliability through adaptive control parameter adjustment based on operating conditions.
Solution Approach 2:
The control loop exhibits dynamic reconfiguration capability, transitioning between different control modes seamlessly. The controller adjusts PWM generation parameters, comparator thresholds, and feedback gain dynamically based on the detected operation mode, ensuring optimal control performance for each mode without requiring static hardware duplication.
3Measurement precision
If high resolution PWM signal generation is provided for low load conditions, then the measurement precision is improved, but the device complexity and cost increase
Solution Approach 1:
The patent implements dynamic resolution adjustment in the PWM signal generation circuit. The controller adapts the PWM signal resolution based on the detected operation mode and load conditions, providing high resolution (e.g., 10-bit equivalent) during low load operation where precision is critical, and automatically reducing to lower resolution during high load conditions where the absolute timing precision requirements are relaxed, thereby optimizing resource utilization.
4Manufacturing precision
If external slope generator components are used, then the manufacturing precision of the control signal is improved, but the device complexity and size increase
Solution Approach 1:
The patent integrates the slope generation functionality directly into the PWM controller IC, merging previously separate external components (oscillator, ramp generator, comparator) into a unified integrated circuit. This integration eliminates the need for external slope generator components while maintaining the precision required for accurate PWM duty cycle control across different operating modes.
Solution Approach 2:
The integrated PWM controller provides multiple functions within a single device, including oscillation generation, slope/ramp signal generation, PWM comparison, and multi-mode control logic. This universal controller replaces what would traditionally require multiple discrete external components, reducing board space and assembly complexity while maintaining control signal accuracy.
5Device complexity
If software emulation of slope generator is used, then the device complexity is reduced, but the productivity and resolution of the generated ramp signal decrease
Solution Approach 1:
The patent replaces software-based slope generation with dedicated hardware circuitry integrated into the PWM controller. The hardware slope generator uses analog or digital circuits to produce the ramp signal at the required switching frequency (hundreds of kHz to MHz) with sufficient resolution, eliminating the computational overhead and resolution limitations of software-based approaches while maintaining low device complexity through integration.
Data Source
AI summary
In various embodiments a controller for controlling the operation of a switched mode power supply is provided, the controller comprising: a first signal source configured to provide a first set of signals including a set signal and a clear signal, wherein the first set of signals may correspond to a first mode of operation of the switched mode power supply; a second signal source configured to provide a second set of signals including a set signal and a clear signal, wherein the second set of signals may correspond to a second mode of operation of the switched mode power supply; a selecting circuit coupled to the first signal source and to the second signal source, the selecting circuit being configured to select either the first set of signals or the second set of signals; a switching signal generating circuit coupled to the selecting circuit and configured to provide a switching signal to the switched mode power supply based on the set of signals received from the selecting circuit.