Coded Light Modulation Arrangement for LED Power Efficiency
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Solution Overview
Problem
Existing coded light modulation systems for LED light sources suffer from high power consumption due to the need for a post-regulator and resistor to absorb excess energy, leading to inefficient energy use when modulating light intensity for data transmission.
Innovation Solution
A coded light modulation arrangement that uses an energy storage system to divert current during logic low emissions and release stored energy during logic high emissions, eliminating the need for additional power consumption by using switches and energy storage devices like capacitors to modulate the drive current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a post-regulator and resistor are used to modulate LED current for coded light communication, then light intensity modulation is achieved, but power consumption increases significantly
Solution Approach 1:
The patent applies preliminary action by pre-charging energy storage capacitors during periods when LED current is not needed for communication modulation. The capacitors are charged from the rectified DC voltage before the modulation phase, so that when coded light transmission is required, the pre-stored energy is used to drive the LED without requiring additional power from the post-regulator, thus avoiding continuous high power consumption.
Solution Approach 2:
The patent changes the operational parameters by switching between different current paths - during normal operation, LED current flows directly from the DC-DC converter; during coded light transmission, the path switches to use pre-charged capacitor energy. This parameter change allows the system to achieve light intensity modulation for communication while minimizing power consumption by utilizing stored energy rather than continuous regulator operation.
2Loss of energy
If additional energy storage devices and switches are added to reduce power loss, then power efficiency improves, but device complexity increases
Solution Approach 1:
The patent applies multi-functionality by designing the energy storage capacitors to serve dual purposes: they function as filter capacitors for the rectified DC voltage during normal power conversion, and simultaneously serve as energy sources for coded light modulation when communication is required. The existing DC-link capacitors in the power supply circuit are utilized for both power filtering and communication energy storage, eliminating the need for separate dedicated energy storage components and reducing overall circuit complexity.
Solution Approach 2:
The patent implements self-service by enabling the existing power supply capacitors to automatically provide the necessary energy for coded light modulation without requiring external or additional energy storage devices. The system uses its own internal capacitor bank, which is already present for power rectification and filtering, to serve the dual function of power supply stabilization and communication energy source, thereby avoiding added complexity from separate energy storage circuits.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for low power loss coded light modulation, enabling LED light sources to transmit data without significant increases in energy consumption, thus providing added functionality with minimal additional energy costs.
Implementation Method 1
an energy storage arrangement comprising a number of energy storage devices; a switch arrangement comprising a number of switches... in a charging switch configuration corresponding to the logic low, a negative modulation current is diverted from a drive current of the light-emitting load to the energy storage arrangement such that the LED is adapted to emit a low radiant flux level and an energy of the diverted current is adapted to be stored at the energy storage arrangement
Data Source
AI summary
The invention describes a coded light modulation arrangement (1), adapted to be connected between a driver (31) and a LED (3), which coded light modulation arrangement (1) comprises input terminals (10) adapted to connect to the driver (31) and to receive a drive current (IDRIVE), an energy storage arrangement comprising a number of energy storage devices (E1, E2); a data input interface (12) realized to receive a data stream (D), said data stream (D) comprises a sequence of binary symbols comprising a logic high and a logic low; a switch arrangement comprising a number of switches (S1, S2) arranged to connect the energy storage devices (E1, E2) of the energy storage arrangement and to modulate the drive current such that, in a charging switch configuration corresponding to the logic low, a negative modulation current (INEG) is diverted from a drive current (IDRIVE) of the LED (3) to the energy storage arrangement; and, in a discharging switch configuration corresponding to the logic high, a positive modulation current (IPOS) is drawn from the energy storage arrangement and added to the drive current (IDRIVE) of the LED (3); and output terminals (11) adapted to connect to the LED (3) and to provide the modulated drive current directly to the LED (3) to emit the low and high radiant flux level as coded light (Lcoded) to be received by a photosensor of a coded light receiver device. The invention further describes a method of performing coded light modulation for light emitted by a LED (3); a luminaire; and a coded light communication arrangement (5).