Linear-nonlinear control applied to buck converters to get fast transient response

To feed the latest generation of microprocessors and DSP is one of the main challenges for power supply designers. Both high current slew rates together with low output voltage are required. Firstly, the designer tries to comply with previous requirements optimizing the power stage and the control loop bandwidth, but if it is not enough then new strategies are needed. In this paper, a novel control technique is presented. The proposed combined linear-nonlinear control (LnLC) increases significantly the capability of a conventional linear control to reduce the recovery time of the output voltage drop produced when a load current step occurs. Experimental results have been obtained for two cases: a synchronous rectifier buck converter, with a conventional voltage loop and the same converter with the novel LnLC. The comparison of these experimental results validates the proposed idea.

[1]  A. Barrado,et al.  Theoretical study and implementation of a high dynamic performance, high efficiency and low voltage hybrid power supply , 2001, 2001 IEEE 32nd Annual Power Electronics Specialists Conference (IEEE Cat. No.01CH37230).

[2]  J. Sebastian,et al.  Optimized synchronous rectification stage for low output voltage (3.3 V) DC/DC conversion , 1994, Proceedings of 1994 Power Electronics Specialist Conference - PESC'94.

[3]  P. Wood,et al.  Synchronous rectifiers versus Schottky diodes: a comparison of the losses of a synchronous rectifier versus the losses of a Schottky diode rectifier , 1994, Proceedings of 1994 IEEE Applied Power Electronics Conference and Exposition - ASPEC'94.

[4]  Peng Xu,et al.  The active-clamp couple-buck converter-a novel high efficiency voltage regulator modules , 2001, APEC 2001. Sixteenth Annual IEEE Applied Power Electronics Conference and Exposition (Cat. No.01CH37181).

[5]  Peng Xu,et al.  Comparison of three topology candidates for 12 V VRM , 2001, APEC 2001. Sixteenth Annual IEEE Applied Power Electronics Conference and Exposition (Cat. No.01CH37181).