This digest presents small-signal design methods for the CMC architectures using a type-II controller, and the performance limits are identified using a stable pole/zero cancelation approach. Thereafter, a trajectory-based design approach is developed to identify critical performance limits using a resettable PI controller, which can achieve near time optimal performance with and without a peak current limit. Start-up performance is shown to be further improved by using a low voltage LED string, however, at the cost of an increasing pin count. Finally, a method is identified to achieve smooth controller transitions in a peak current based constant on/off-time multimode controller. Experimental results of a few commercial LED drivers are presented, and the performance limits are identified. For the same specs, the performance improvement using the proposed design framework is demonstrated using simulation results.
