Satellite LNB Power Supply Adaptive Load Waveform Control
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Solution Overview
Problem
Satellite receiver systems face challenges in maintaining a proper 22 kHz waveform shape due to insufficient current sinking, especially with the transition from high to low output voltage, which affects signal selection and polarization switching, particularly with increasing capacitive loads and zero load current specifications.
Innovation Solution
An adaptive load system is introduced that supplies varying currents based on control signal transitions and tone presence, utilizing high and low current segments to ensure proper waveform preservation and efficient current management, even at high capacitive loads up to 750 nF.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a linear pass element with emitter follower circuit is used to provide LNB power supply, then the circuit can produce output voltage, but it causes waveform distortion and cannot properly remove charge from external capacitance
Solution Approach 1:
A current sink circuit is introduced as an intermediary component between the emitter follower circuit and the capacitive load. This current sink acts as a mediator that properly removes charge from the external capacitance, enabling the circuit to produce proper 22 kHz waveforms while maintaining the voltage output capability of the emitter follower.
Solution Approach 2:
The patent modifies the circuit parameters by adding controlled current sinking capability. The current sink dynamically adjusts the charge removal rate from the capacitance, changing the electrical parameters to achieve proper waveform shaping while maintaining voltage output.
2Loss of energy
If zero load current specification is implemented at LNB/Switch, then power consumption is reduced, but insufficient sinking current prevents proper 22 kHz waveform production with 750 nF load
Solution Approach 1:
The current sink is designed to be dynamically controllable, adjusting its sinking current based on operational conditions. During tone burst transmission, the current sink provides sufficient current (up to 50 mA) to properly drive the 750 nF capacitive load and produce accurate waveforms. During normal operation, the current sink operates at minimal levels to maintain zero load current specification and reduce power consumption.
Solution Approach 2:
The current sink operates in periodic bursts synchronized with the 22 kHz tone transmission. It provides high sinking current only during the brief periods when tone bursts are transmitted, then returns to minimal operation, thus achieving proper waveform shaping during critical moments while maintaining low average power consumption.
3Manufacturing precision
If simple resistor is added to provide current sink for minimum 30 ma current, then proper waveform can be produced, but it cannot satisfy zero load current specification
Solution Approach 1:
The patent replaces the static resistor-based current sink with a dynamic, controllable current sink circuit. This allows the system to provide high sinking current (30-50 mA) only when needed for waveform shaping during tone transmission, then reduce to minimal current for zero load current operation, achieving both proper waveform and low power consumption.
Solution Approach 2:
The current sink parameter (sinking current magnitude) is dynamically changed based on operational mode. The circuit transitions between high current mode (for waveform shaping during tone bursts) and zero/minimal current mode (for normal operation), thereby satisfying both waveform quality and power consumption requirements.
Data Source
AI summary
A method of processing an LNB power supply output signal comprising providing an LNB selection signal to select a first of the plurality of LNB signals as the input signal, superimposing a tone onto the LNB selection signal to select a second of the plurality of LNB signals as the input signal, providing a first transponder selection voltage to select a first set of transponders within the input signal, providing a second transponder selection voltage to select a second set of transponders within the input signal, and activating an adaptive load to preserve the tone if the second of the plurality of LNB signals is selected.