LED Chain Control via Common Line and Voltage Dividers
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Solution Overview
Problem
Existing light-emitting diode (LED) chain systems require extensive wiring and incur additional costs due to individual comparators and drive lines, making them inefficient and costly, especially in applications like motor vehicles.
Innovation Solution
A light-emitting diode chain design where each control circuit has a series circuit with a reference voltage sink and a controlled switch, using a common control line for all LEDs, reducing wiring to three lines and employing transistors (MOSFETs) with protective diodes and resistors to manage voltages, allowing for a compact and inexpensive drive circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual comparators are assigned to each controlled switch, then switching control precision is improved, but wiring complexity and cost increase
Solution Approach 1:
The patent merges the comparator functionality into a single shared comparator that is common to all controlled switches. Instead of having separate comparators for each LED, one comparator is used to compare the control voltage with reference voltages generated by voltage dividers, thereby reducing wiring complexity while maintaining switching control precision through the shared comparison mechanism.
Solution Approach 2:
The single comparator serves multiple functions by being shared across all controlled switches in the LED chain. It universally compares the control voltage against different reference voltages (generated by different voltage dividers) to control multiple LEDs, thereby eliminating the need for individual comparators and reducing overall system complexity.
2Adaptability or versatility
If individual drive lines are provided for each LED, then individual LED control capability is improved, but wiring effort increases
Solution Approach 1:
The patent merges multiple drive lines into a single common control line that is shared by all controlled switches. The individual LED control capability is maintained through the use of different reference voltages generated by voltage dividers, which allow the single comparator to selectively control different LEDs based on the control voltage level, thereby reducing wiring effort while preserving individual control capability.
Solution Approach 2:
The patent introduces voltage dividers as intermediary elements that generate different reference voltages from a common reference voltage source. These voltage dividers act as mediators that enable the single comparator to differentiate between multiple LEDs and control them individually through a single control line, thereby maintaining adaptability while reducing wiring complexity.
3Measurement precision
If comparators are provided for each switch, then switching accuracy is improved, but cost increases
Solution Approach 1:
The patent merges multiple comparator functions into a single shared comparator, thereby reducing the number of expensive comparator components required. The switching accuracy is maintained through the use of different reference voltages generated by voltage dividers, which allow the single comparator to accurately control multiple LEDs without requiring multiple expensive comparator ICs, thereby reducing manufacturing cost while preserving switching accuracy.
Solution Approach 2:
The patent replaces expensive comparator ICs with a single comparator combined with simple voltage divider circuits using passive resistors. The voltage dividers act as disposable, low-cost elements that generate the necessary reference voltages without requiring expensive active components, thereby reducing manufacturing cost while maintaining switching accuracy through the comparator's precise voltage comparison capability.
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 solution significantly reduces wiring complexity and cost, enabling a compact and efficient LED drive circuit suitable for motor vehicle applications, with reliable switching and lighting control using a common control line and voltage ramp generator.
Implementation Method 1
the reference voltage sink is formed by at least one reference voltage diode, with the reference voltage diode advantageously being a zener diode
Implementation Method 2
A practical variant provides for the semiconductor switches (Q1) to be transistors, in particular MOSFETs
Implementation Method 3
a light-emitting diode chain with a plurality of light-emitting diodes connected in series
Data Source
Figure 1
Figure 2~8
Figure 3
AI summary
A light-emitting diode chain comprising a plurality of light-emitting diodes (LED1....LED4) which are connected in series and fed by a power source, in which each light-emitting diode is assigned an actuating circuit (5) that has a series circuit of a reference voltage sink (D1) of the voltage (Uref) and of a controlled switch (Q), said circuit being connected in parallel to the light-emitting diode and designed to compare the control voltage (Ust) on a common control line (4) for all actuating circuits, measured against a base point of the LED series circuit, to the voltage at the connection of the switch to the subsequent LED in the chain or the base point and to close or open the switch if the control voltage (Ust) falls below a specified value or exceeds a specified value.