Variable Reset Current Control for LED Dimmer TRIAC
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Solution Overview
Problem
Conventional LED driving circuits experience significant circuit loss during the reset process of a dimmer TRIAC, as they require a large reset current to reliably reset the dimmer, leading to inefficiencies and increased energy consumption.
Innovation Solution
A reset current control circuit and method that generates a variable reset current, adjusting it in a step mode after the dimmer is turned off, maintaining it at different current levels based on LED driving current and direct current bus voltage thresholds to minimize circuit loss and improve efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large reset current is supplied to reset the dimmer TRIAC, then the reset reliability is improved, but the circuit loss increases
Solution Approach 1:
The patent applies dynamics by making the reset current variable rather than constant. The control circuit dynamically adjusts the reset current in two stages: initially providing a larger current to ensure reliable dimmer reset, then reducing to a smaller maintenance current once reset is achieved. This dynamic adjustment resolves the contradiction by providing high current only when necessary for reliability, rather than continuously, thereby reducing overall circuit loss.
Solution Approach 2:
The patent implements periodic action through its two-stage reset current strategy. The first stage provides a higher reset current for a limited initial period to ensure reliable dimmer turn-off. The second stage transitions to a lower maintenance current for the remaining period. This periodic variation in current magnitude achieves reliable reset while minimizing energy loss during the extended reset process.
2Speed
If a large reset current is supplied to reset the dimmer TRIAC, then the reset speed is improved, but the voltage drop causes increased loss on parallel resistor
Solution Approach 1:
The control circuit dynamically adjusts the reset current in two stages: initially providing a larger current to ensure reliable dimmer reset, then reducing to a smaller maintenance current once reset is achieved. This dynamic adjustment resolves the contradiction by providing high current only when necessary for reliable reset, rather than continuously, thereby reducing overall circuit loss.
Solution Approach 2:
The patent applies partial action by providing a large reset current only for the initial portion of the reset process when it is most needed to ensure reliable dimmer turn-off. Once the dimmer is successfully reset, the current is reduced to a smaller maintenance level. This partial application of high current achieves the necessary reset speed while avoiding excessive current that would cause unnecessary voltage drops and resistor losses.
Data Source
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AI summary
A reset current control circuit (42), a reset current control method and an LED driving circuit are provided. A reset current is generated in a case that it is detected that a dimmer is in an off state, to reset the dimmer. The reset current is variable and has a contrary variation trend to a direct current bus voltage of the LED driving circuit, such that a circuit loss of the dimmer during the reset process is reduced, thereby improving the efficiency of the circuit.