Trailer Detection Circuit Using Capacitive Current Pulses
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Solution Overview
Problem
Current systems fail to detect the presence of trailers equipped with LED rear lamps, as they rely on the low cold resistance of filament bulbs, which is not applicable to LED lamps, leading to incorrect detection and operational issues.
Innovation Solution
A circuit that simulates the presence of a filament bulb by generating a short-time high current sink during test pulses, mimicking the behavior of a bulb-equipped trailer, while minimizing power consumption and avoiding light emission from the LED lamp.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a resistor is added in parallel to the LED device to increase current consumption, then the current consumption increases to a value similar to bulb-equipped rearlamps, but the current in the resistor is parasitic and ever present, having no functional sense and increasing power consumption
Solution Approach 1:
The patent applies periodic action by using a capacitor to generate test pulses at specific intervals (e.g., when ignition is activated) rather than maintaining continuous current flow. The capacitor charges during normal operation and discharges in periodic test pulses to simulate filament behavior temporarily, enabling detection only when needed. This resolves the contradiction by providing accurate detection during test pulses while avoiding continuous parasitic current consumption.
2Measurement precision
If test pulses are applied with duration of 1ms to 3ms to measure current flow, then the filament does not heat up and emit light, but the current on LED-equipped rearlamps is only about 200mA to 350mA, which is insufficient for detection
Solution Approach 1:
The patent introduces a capacitor as an intermediary component that bridges the gap between LED lamps and the detection system designed for filament bulbs. The capacitor temporarily stores and releases energy to create high-current test pulses that simulate filament behavior, allowing the detection system to recognize LED-equipped trailers as compatible with bulb-equipped ones. This intermediary enables both short-duration non-heating test pulses and sufficient current magnitude for reliable detection.
3Measurement precision
If the circuit uses the low cold resistance of filaments in bulbs to detect trailer connection, then the detection system works with bulb-equipped rearlamps, but it does not work on trailers equipped with rearlamps with LEDs as light sources
Solution Approach 1:
The patent applies parameter changes by dynamically altering the electrical characteristics of the LED circuit during test pulses. The capacitor causes a temporary change in current magnitude and flow pattern that transforms the LED lamp's electrical signature to match the cold filament resistance profile. This parameter transformation allows the detection system to interpret LED lamps as filament bulbs, achieving compatibility across different lamp types while maintaining accurate detection.
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
Enables accurate detection of trailer connection by simulating the current consumption of a bulb-equipped trailer, allowing for consistent operation with LED lamps without heating them, thus resolving the detection issues with LED-equipped trailers.
Implementation Method 1
a capacitor (14) is connected in parallel to the LED device (12)
Data Source
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AI summary
It is described a circuit for controlling the presence of a trailor connected to a towing truck, via the control of the electric current flow in the rear LED lamps (2) of the trailor, comprising means (1) for simulating the presence of a filament of a bulb lamp in a LED lamp, by increasing the current consumption of the LED lamp (2) with an additional current component in the form of one or more current pulses, only for a given dedicated time such that the LED lamp (2) does not emit light.