Current Compensation Circuit for LED Driver Turn-On Delay

The patent implements a feedback mechanism where the turn-on delay time is measured and fed back into the control system. This measured delay information is then used to adjust the turn-off timing of the MOSFET, creating a closed-loop control system that automatically compensates for delays. The feedback approach maintains control accuracy without requiring overly complex external circuitry, as the system uses its own operational characteristics to self-correct.

The control circuit uses the MOSFET's own turn-on delay characteristic to determine its optimal turn-off point. By measuring the delay inherent in the specific MOSFET device and using that measurement to control the same device's operation, the system makes the device self-regulating. This self-service approach simplifies the overall control architecture compared to using complex external compensation circuits.

The patent measures the turn-on delay time in advance before peak current mode control operations begin. This pre-measured delay value is then used to predict and adjust the turn-off point, ensuring that even with fast response speeds, the current doesn't drop below zero. The preliminary measurement allows the system to maintain both speed and accuracy.

The system prepares compensation for the turn-on delay by measuring it beforehand and using this information to set appropriate operating parameters. This beforehand cushioning ensures that when the MOSFET does exhibit its inherent delay, the control parameters are already adjusted to account for it, preventing the current from dropping below zero while maintaining fast response.