Third Order Converters with Current Output for Driving LEDs

Light emitting diodes LEDs are highly efficient in changing electrical energy into light. The applications are lightning, but also medical treatments, and disinfection. After a short discussion of the simplest converter which is based on the Buck converter several third order current converters, which are suitable to drive an LED load, are treated. The Buck converter with input filter, the output current Boost converter, and the output current Cuk converter are shortly treated, but for the other topologies simple control techniques are given. These converters are the current output converter based on the Zeta converter, two converters with a quadratic term of the duty cycle in the voltage transformation ratio, the quadratic step-down converter with current output and the D square divided by one minus d current output converter, which is a step-up-down converter, and two converters which function only for a limited duty cycle, the (2d-1)/d step-down and the (2d- 1)/(1-d) step-up-down output current converters. The dynamics of example converters is shown with the help of LTSpice simulations.