SCR-Compatible Constant-Voltage LED Dimming Circuit
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Solution Overview
Problem
Existing SCR applications primarily operate in constant-current regulation circuits, but there is a growing need for constant-voltage regulation, necessitating improved compatibility and stable voltage provision to loads.
Innovation Solution
A silicon-controlled rectifier (SCR)-compatible constant-voltage circuit is developed, incorporating an input undervoltage control module, overpower protection module, and controllable load module, connected in parallel with a power conversion module to ensure reliable constant voltage delivery to loads, with the power conversion module converting electric signals to a constant voltage and controlling operations based on reference voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SCR is used in constant-current regulation circuits, then the SCR can be effectively controlled, but it cannot provide constant voltage to the loads
Solution Approach 1:
The patent makes the SCR circuit capable of both constant-current and constant-voltage regulation by introducing a parallel power conversion module. This module can operate in different modes to provide either constant current or constant voltage to the load, making the circuit universal and adaptable to different regulation needs while maintaining SCR control reliability.
Solution Approach 2:
The patent introduces a power conversion module as an intermediary component between the SCR and the load. This mediator converts electric signals from the power supply into constant voltage output, enabling the SCR circuit to provide stable voltage to the load without compromising the SCR's control reliability.
2Reliability
If the power conversion module operates continuously, then stable voltage can be provided, but the SCR may turn off under certain conditions
Solution Approach 1:
The patent introduces a controllable load module that provides preliminary action by ensuring a minimum load is always present on the SCR. This prevents the SCR from turning off due to lack of load current, maintaining its conduction state and ensuring continuous stable voltage output from the power conversion module.
Solution Approach 2:
The patent implements feedback control where the controllable load module monitors the SCR's conduction state and adjusts the load accordingly. When the SCR approaches turn-off conditions, the feedback mechanism increases the load to maintain minimum current, thereby stabilizing the SCR's conduction state and ensuring continuous operation of the power conversion module.
3Object-affected harmful factors
If protection modules are added to prevent overpowers and undervoltage, then safety is improved, but the device complexity increases
Solution Approach 1:
The patent merges the protection functions into integrated control modules that work with the existing power conversion module. The input undervoltage control module and overpower protection module are combined with the power conversion module to share control circuitry and processing resources, providing comprehensive protection while minimizing the increase in overall device complexity.
Solution Approach 2:
The control modules in the patent are designed to perform multiple functions: they provide both protection (overpower and undervoltage prevention) and normal operation control. This multi-functionality reduces the need for separate dedicated protection circuits, thereby limiting the increase in device complexity while still achieving comprehensive safety coverage.
Data Source
AI summary
A silicon-controlled rectifier (SCR)-compatible constant-voltage circuit that includes an input undervoltage control module, an overpower protection module, a controllable load module, and a power conversion module is provided. The input undervoltage control module, the overpower protection module, and the controllable load module are connected in parallel between a first sampling point and the power conversion module, and the first sampling point is arranged between an SCR and the power conversion module. The power conversion module is configured to provide a constant voltage to a load module. The input undervoltage control module and the overpower protection module are configured to control the power conversion module to start or stop power conversion based on a voltage at the first sampling point. The controllable load module is configured to maintain the SCR to be on when the power conversion module stops power conversion.