Stability analysis of a universal LED driver

In the present work, stability analysis of a universal LED driver, when it operates 18W-72W LED modules on universal AC supply, is carried out. The stability analysis is performed by formulating the mathematical model of the LED driver and obtaining the system characteristics from the phase margin test using Bode plots. The nature of step response of the modeled universal LED driver for all the considered LED modules is found to be similar to the corresponding current waveforms obtained from MATLAB Simulink simulation. The variation of phase margin and settling time with the ratio of number of LED chips connected in series to number of LED chips connected in parallel (N
_s
/N
_p
ratio) are studied to ascertain the N
_s
/N
_p
ratio of LED modules for optimized performance of the LED driver in the given output power range.