LED Field Control Circuit with Voltage Spike Suppression
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Solution Overview
Problem
Existing methods for controlling light-emitting diode (LED) circuits in series connections fail to allow arbitrary adjustment of brightness and can cause voltage increases due to sequential power supply, and do not effectively handle LED failures such as short circuits or current interruptions.
Innovation Solution
The control and/or regulating means activates the current source shortly before the end of a pulse duration and reduces current as the switching element opens, allowing for diagnosis of LED failures by detecting voltage across the series circuit during a dedicated diagnosis time, and adjusts switching times to maintain brightness and prevent voltage spikes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sequential power supply of series circuits is used to enable failure detection, then LED failure detection capability is improved, but voltage increases in the supply line occur and brightness adjustment flexibility is reduced
Solution Approach 1:
The patent applies preliminary action by introducing a diagnosis time period before normal operation, during which only one series circuit is activated to establish a reference voltage state. This preliminary measurement enables detection of LED failures by comparing voltage deviations during subsequent parallel operation, thereby detecting failures without causing harmful voltage spikes during normal brightness control.
2Adaptability or versatility
If controllable switching elements are activated in parallel to allow arbitrary brightness adjustment, then brightness control flexibility is improved, but instantaneous voltage increases occur in the supply line
Solution Approach 1:
The patent implements feedback by continuously monitoring the voltage in the supply line during parallel operation of series circuits. When voltage deviations exceeding a threshold are detected, the system responds by switching to sequential activation mode for affected circuits. This feedback mechanism maintains brightness control flexibility while preventing harmful voltage spikes by dynamically adjusting the operation mode based on real-time voltage conditions.
3Reliability
If diagnosis time is introduced for failure detection, then LED failure detection is improved, but clock period duration increases
Solution Approach 1:
The patent merges the diagnosis function with the normal operation cycles by integrating voltage measurements taken during regular brightness control into the failure detection process. The same voltage sensor and control circuitry used for brightness regulation are also utilized for failure detection, eliminating the need for separate dedicated diagnosis time periods and thus avoiding significant increases in clock period duration.
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 enables reliable detection and handling of LED failures, maintains average brightness, and prevents instantaneous voltage increases in the supply line, ensuring the functionality and longevity of the LED field.
Implementation Method 1
a light-emitting diode field (D1, D2, D3) in series with the power source (I)
Implementation Method 2
with a voltage sensor (V1), wherein the controllable switching elements and the power source are controlled by the control and/or regulating means
Data Source
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AI summary
The present invention relates to a method for operating a circuit arrangement having a power source (I), - having a light-emitting diode field (1, 2, 3) in series to the power source (I), wherein the light-emitting diode field (1, 2, 3) comprises at least two series circuits (1, 2, 3) which comprise at least one light-emitting diode (D1, D2, D3) and a controllable switching element (S1, S2, S3), comprising a control and/or regulation means (C) for the light-emitting diode field (1, 2, 3) and - comprising a voltage sensor (V1), wherein the controllable switching elements and the power source (I) are actuated by the control and/or regulation means (C) in such a way that the control and/or regulation means (C) actuate the closing of the controllable switching element (S1, S2, S3) of at least one series circuit (1, 2, 3) of the light-emitting diode field (1, 2, 3) by a control pulse at the control input of the controllable switching element (S1, S2, S3) during a cycle period (Tcycle) for a pulse duration (T1, T2, T3) determined by the control and/or regulation means (C) and - that the control and/or regulation means (C) actuate the power source (I) shortly before or at the latest simultaneously with the end of a pulse duration (T1, T2, T3) such that the current is reduced, specifically by the amount of current through the series switching (1, 2, 3), the controllable switching element (S1, S2, S3) of which is actuated to open at the end of the pulse duration (T1, T2, T3) by the control and/or regulation means (C). During successive cycle periods (Tcycle), one of each of the controllable switching elements of the series circuits (1, 2, 3) is switched on alone by the control and/or regulation means (C) for a period of time referred to as a diagnosis time (Tdiag).