X-Capacitor Discharge Circuit for Distorted Power-Off Detection

The patent applies dynamics by making the discharge circuit configurable between two states: a low-power state during normal operation and a high-power discharge state when needed. The controller dynamically switches between using the small discharge resistor (low power consumption) and the large discharge transistor (high power consumption) based on the actual discharge requirements, thus resolving the contradiction between maintaining discharge capability and minimizing energy loss during normal operation.

The patent segments the discharge function into two distinct circuits: a first discharge circuit with a small discharge resistor for low-power operation, and a second discharge circuit with a large discharge transistor for rapid discharge. By dividing the single discharge function into multiple specialized circuits, the system can select the appropriate circuit based on operational needs, achieving both energy efficiency and effective discharge capability.

The controller dynamically adjusts the discharge strategy by monitoring the voltage across the X-capacitor. When the voltage is high and rapid discharge is needed, the controller activates the large discharge transistor for efficient discharge. When the voltage is already low or during normal operation, the controller uses only the small discharge resistor to minimize power consumption. This dynamic adaptation resolves the contradiction between discharge efficiency and energy savings.

The patent creates two specialized discharge circuits with different characteristics: a first discharge circuit optimized for low power consumption and a second discharge circuit optimized for high discharge efficiency. The controller segments the discharge task by selecting which circuit to activate based on the current voltage level and discharge requirements, thus achieving both energy efficiency and adequate discharge performance.

The controller serves multiple functions: it monitors the voltage across the X-capacitor, determines when discharge is needed, selects which discharge circuit to activate, and controls the discharge process. By making the controller multi-functional, the patent avoids adding separate dedicated monitoring and control circuits, thus achieving safety compliance without proportionally increasing system complexity.

The patent merges the voltage monitoring function, discharge decision-making function, and discharge control function into a single controller unit. This consolidation reduces the overall system complexity compared to having separate dedicated circuits for each function, while still maintaining comprehensive safety monitoring and control capabilities required by safety standards.