Dynamic Control Circuit for LED Dimming Ripple Reduction

The patent implements a dynamic control circuit that adjusts the impedance of the buffer capacitor based on operating conditions. The control circuit monitors LED current and dynamically modifies the capacitor's effective impedance to reduce current ripple at low dimming levels without requiring a physically larger capacitor. This dynamic adjustment allows the same physical capacitor to provide different levels of ripple filtering depending on the operating point.

The patent changes the electrical parameters of the buffer capacitor dynamically by controlling its impedance through an active control circuit. The control circuit adjusts the capacitor's effective impedance value based on the LED current level, enabling the capacitor to provide optimal ripple filtering at each operating point without changing its physical size or capacitance value.

The patent replaces the static power-dissipating resistor with a dynamic control circuit that adjusts the buffer capacitor's impedance only when needed. The control circuit monitors LED current and activates impedance adjustment only at low dimming levels where ripple becomes problematic, rather than continuously dissipating power as a resistor would. This dynamic approach eliminates unnecessary energy loss while maintaining ripple suppression only when required.

The patent uses a control circuit that introduces a temporary, controlled impedance effect only when needed to suppress ripple, rather than permanently inserting a power-dissipating resistor. The control circuit creates a virtual resistance effect through active control that lasts only during the periods when ripple suppression is needed, avoiding continuous energy dissipation.

The patent implements a feedback control circuit that monitors LED current and detects ripple conditions. The control circuit uses this feedback information to dynamically adjust the buffer capacitor's impedance when ripple becomes excessive. This closed-loop control allows high-efficiency LEDs to operate without the ripple problems that would otherwise result from their low ESR, as the control circuit compensates for the decreased natural damping.

The patent changes the electrical parameters of the buffer capacitor dynamically to compensate for the low ESR of high-efficiency LEDs. The control circuit adjusts the capacitor's effective impedance based on the operating point, enabling optimal ripple filtering that adapts to the reduced natural damping provided by low-ESR LEDs. This parameter adjustment allows high-efficiency LEDs to maintain stable operation across all dimming levels.