Improved LNB power circuit design for enhanced reliability by current limiting control

Abstract

Low Noise Block (LNB) circuits are an essential component of satellite receiving systems in televisions. LNB converts high-frequency satellite signals into a lower frequency range for transmission to the receiver. Also, LNB ensures low-noise signal reception, enables polarization control, supports multiple frequency bands, and amplifies signals. The LNB power circuits provide power to the LNB. Voltage-controlled boost converters are commonly used in these circuits; the current limiting feature used in these circuits can be insufficient to handle sudden current spikes, leading to feedback from end users. They are not immune to short circuits because of installation problems with satellite cables, which are a common failure mode that potentially damages the LNB power or other components in the television, resulting in a loss of satellite signal. Hence, leading to a poor user experience and harming the manufacturer's reputation. Replacing a damaged LNB power circuit is also difficult b ecause i t i s o ften i ntegrated i nto t he T V's d esign and is not easily replaceable. To mitigate this problem, a parallel resonant converter approach is introduced that limits the output current up to a pre-defined l evel b y f requency c ontrol, which provides an alternative to voltage-controlled boost converters. Parallel resonant converter circuits operate as current sources so maximum current cannot exceed this defined operation frequency point under any circumstances. In this study, the mathematical equations of the proposed circuit were obtained, and then the operating conditions were determined. The operation frequency ranges were interpreted graphically using Matlab, and the parallel resonant converter design was evaluated using simulation model by using MATLAB's Simulink Toolbox. These results show that the parallel resonant converter approach maintaining a stable current and reducing the risk of short circuit damage. The proposed design is expected to reduce repair costs due to LNB power circuits for TV manufacturers.