Preprint Article Version 1 Preserved in Portico This version is not peer-reviewed

Discrete-Time Modeling of High Power Asymmetric Half-Bridge LED Constant-Current Driver Controlled by Digital Current Mode

Version 1 : Received: 3 December 2020 / Approved: 4 December 2020 / Online: 4 December 2020 (10:09:24 CET)

How to cite: Qiao, Z.; Wang, S.; Wang, R.; Shi, Y.; Zhang, N.; Liu, Z. Discrete-Time Modeling of High Power Asymmetric Half-Bridge LED Constant-Current Driver Controlled by Digital Current Mode. Preprints 2020, 2020120096 (doi: 10.20944/preprints202012.0096.v1). Qiao, Z.; Wang, S.; Wang, R.; Shi, Y.; Zhang, N.; Liu, Z. Discrete-Time Modeling of High Power Asymmetric Half-Bridge LED Constant-Current Driver Controlled by Digital Current Mode. Preprints 2020, 2020120096 (doi: 10.20944/preprints202012.0096.v1).

Abstract

The high-power Asymmetric half-bridge Converter (AHBC) LED constant current driver controlled by digital current mode is a fourth-order system. Static operating point, parasitic resistance, load characteristics, sampling effect, modulation mode and loop delay will have great influence on its dynamic performance. In this paper, the small-signal pulse transfer function of the driver is established by the discrete-time modeling method for the two operating points corresponding to the three modulation modes of the trailing edge, leading edge and double edge. And, the effects of parasitic parameters, delay effect, sampling effect and load effect are fully considered in modeling. For a large number of complex exponential matrix operations, the first order Taylor formula is used for approximate calculation after the coefficient matrix is obtained by substituting the data. Then, Matlab software is used to compare and analyze the discrete-time model and the discrete-average model. The results show that the proposed discrete-time model can more accurately characterize the resonant peak and high-frequency dynamic characteristics, and is very suitable for the design of high frequency digital controller.

Subject Areas

AHB LED constant-current driver; Digital Current-programmed control; discrete-time modeling; Modulation effect

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