Thyristor Dimming Control Circuit With Fixed Bleed Time
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Solution Overview
Problem
Conventional control systems for LED dimming with thyristors face inefficiencies due to the inability to control the time period of the bleed-off current, affecting the maintenance of the thyristor in a normal on state when the main path current is lower than the sustaining current.
Innovation Solution
A control circuit and method with a detection module, timing module, control module, and bleeder module that allows for fixed bleed time, where a trigger signal initiates timing, an end-of-timing signal controls the bleeder module to bleed off current within a preset time, and all modules perform a power-off reset, enabling efficient operation of the thyristor at maximum angle during dimming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bleed-off current path is always on to maintain the thyristor in a normal on state, then the thyristor can be sustained, but the efficiency of the system would be affected
Solution Approach 1:
The patent implements periodic action by controlling the bleed-off current path to operate only during specific time intervals (first time interval) rather than continuously. The control circuit activates the bleed-off current path periodically based on timing signals, allowing the thyristor to be sustained during critical periods while minimizing energy consumption during non-critical periods when the main current is sufficient.
2Reliability
If the current of the control system is less than the minimum sustaining current, then the thyristor will be turned off, but providing continuous bleed-off current reduces system efficiency
Solution Approach 1:
The patent applies dynamics by making the bleed-off current path dynamically controllable rather than static. The control circuit adjusts the activation of the bleed-off current path based on real-time conditions, using a control signal generated by comparing timing signals with threshold values. This dynamic control allows the system to provide bleed-off current only when necessary to maintain the thyristor in the on state, optimizing both reliability and efficiency.
3Reliability
If a bleed-off current path is always on, then the thyristor can be maintained in a normal on state, but the efficiency of the system would be affected
Solution Approach 1:
The patent implements periodic action by controlling the bleed-off current path to operate only during specific time intervals (first time interval) rather than continuously. The control circuit activates the bleed-off current path periodically based on timing signals, allowing the thyristor to be sustained during critical periods while minimizing energy consumption during non-critical periods when the main current is sufficient.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the operational parameters of the bleed-off current path. The control circuit changes the activation state of the bleed-off current path based on timing signals and threshold comparisons, transitioning between active and inactive states. This parameter change allows the system to optimize energy consumption by providing bleed-off current only when the main current is insufficient to maintain the thyristor.
Data Source
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Figure 3
AI summary
The present application relates to a technical field of electronic circuits, and provides a control circuit and a control method with fixed bleed time, a trigger signal is obtained and transmitted via a detection module; a timing module starts timing upon receiving the trigger signal, and outputs an end-of-timing signal when a preset time is reached; a control module outputs a control signal according to the end-of-timing signal; a bleeder module bleeds off a current within the preset time according to the control signal; and when the control circuit is powered off, the detection module, timing module, control module and bleeder module automatically perform a power-off reset. This achieves a new round of logic control performed by all modules after the power-off reset; with a fixed bleed time, the system can achieve a higher efficiency when the thyristor opens at the maximum angle, and during a thyristor dimming process, the thyristor can be maintained in a normal on state via a bleed-off current when the main path current is lower than the sustaining current of the thyristor, so that the system operates normally.