Boost Converter Current Limit Circuit Duty Cycle Tracking

The patent implements a dynamic current limit circuit that tracks the duty cycle of the boost converter. The current limit is adjusted in real-time based on the duty cycle feedback, making the current limit adaptive to input and output voltage variations. This resolves the contradiction by transitioning from a static fixed voltage clamp to a dynamic tracking mechanism that maintains stable current limiting across varying operating conditions.

The patent employs a feedback mechanism where the duty cycle of the boost converter is monitored and used to adjust the current limit reference. The sample-and-hold circuit captures the duty cycle information, and this feedback is fed back to the current limit circuit to maintain a consistent current limit despite voltage variations. This feedback loop resolves the contradiction by continuously adapting the current limit based on actual operating conditions.

The patent creates a dynamic current limit that adapts to voltage changes while maintaining stability. By using the duty cycle as a tracking parameter, the system dynamically adjusts the current limit reference to compensate for voltage variations. This dynamic adaptation prevents inductor current instability while maintaining the ability to respond to different operating conditions, resolving the contradiction between adaptability and stability.

The patent changes the parameter used for current limiting from a fixed voltage reference to a duty-cycle-dependent reference. This parameter change allows the current limit to automatically adjust with operating conditions while maintaining stability through the proportional relationship between duty cycle and required current limit. The parameter transformation resolves the contradiction by linking current limit directly to the converter's operating state.

The patent implements a current limit circuit that serves multiple functions: it provides stable current limiting, tracks duty cycle variations, and works across different input and output voltage conditions. By making the current limit circuit multi-functional and integrating it with the existing control architecture, the patent reduces the need for separate compensation circuits, thereby limiting the increase in complexity while achieving improved stability.

The patent uses the duty cycle signal as an intermediary to link the control loop with the current limit function. Instead of directly sensing voltage variations and responding with complex compensation, the duty cycle serves as a natural intermediary that already contains information about the converter's operating state. This intermediary approach simplifies the current limit circuit by using an existing signal rather than requiring additional sensing and processing circuitry.