Fixed Bleed-Time Thyristor Control for LED Dimming Stability

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Solution Overview

Problem

Conventional control systems for electronic circuits with thyristors face inefficiencies due to the inability to control the time period of the bleed-off current, affecting the maintenance of a normal on state during LED dimming processes.

Innovation Solution

A control circuit and method with fixed bleed time, comprising a detection module, timing module, control module, and bleeder module, which obtain and transmit trigger signals, start timing, output control signals, and bleed off currents within a preset time, ensuring efficient operation by maintaining the thyristor in a normal on state even when the main path current is lower than the sustaining current.

Engineering Contradictions & Design Principles

VSEngineering 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 reliably, but the system efficiency deteriorates

Engineering Contradiction:

Improvethyristor on state maintenanceVSAvoidsystem efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The bleed-off current is applied periodically rather than continuously. The control circuit activates the bleed-off current only during specific time periods when the thyristor needs maintaining, using a timing mechanism to control the duration and frequency, thus reducing energy waste while ensuring reliable thyristor operation

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The bleed-off current path transitions from a static always-on state to a dynamic controlled state. The control circuit dynamically adjusts the bleed-off current based on real-time system conditions, activating it only when necessary to maintain the thyristor, thereby optimizing the balance between reliability and energy efficiency

Inventive Principle:

Principle #15Dynamics

2Loss of energy

If the bleed-off current is controlled with fixed time to improve efficiency, then energy loss is reduced, but the control system complexity increases

Engineering Contradiction:

Improveenergy loss during dimmingVSAvoidcontrol circuit complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The control circuit is divided into distinct functional modules: a detection module for monitoring system state, a timing module for controlling duration, and a control module for decision-making. This segmentation allows each module to perform a specific function independently, making the overall complex control task manageable and modular

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A timing module is introduced as an intermediary between the detection module and the bleeder module. The timing module receives detection signals and generates timed control signals, mediating the control process to ensure precise timing without requiring complex logic in the final control stage

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11252801B2Control circuit and control method with fixed bleed time

Publication Date: 2022.02.15 SHENZHEN SUNMOON MICROELECTRONICS

AI summary

The present application 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.