LED Driver Power Switch Periodic Control for Heat Reduction
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Solution Overview
Problem
Existing LED drivers face inefficiencies due to fluctuating input voltages affecting current flow and power consumption, leading to increased heat and reduced system efficiency, particularly in linear drive schemes and complex control systems with multiple transistors.
Innovation Solution
A power converter with a capacitor and power switch in series with the LED load, controlled by a circuit to turn off during sinusoidal half-wave periods, concentrating current flow in periods with minimal conduction voltage drop, thereby reducing power consumption and maintaining constant current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the power switch is continuously on to maintain constant current to the LED load, then the current stability is improved, but the power consumption and heat generation of the power switch increase
Solution Approach 1:
The power switch is controlled to operate in periodic on/off cycles rather than continuously. The control circuit turns the power switch on during specific intervals (when input voltage is rising or falling) and off during other intervals, creating a periodic action pattern that reduces average power consumption while maintaining adequate current delivery to the LED load through the capacitor
2Loss of energy
If the power switch is turned off during sinusoidal half-wave periods to reduce power consumption, then the power losses are reduced, but the current flow to the LED load may be affected
Solution Approach 1:
The capacitor is charged in advance during specific intervals when the power switch is on (during input voltage rising or falling edges). This preliminary charging action ensures that when the power switch is turned off during sinusoidal half-wave periods, the capacitor can immediately discharge to maintain current flow to the LED load, thus reducing power losses without significantly affecting current stability
Solution Approach 2:
The capacitor serves as an intermediary energy storage element between the power switch and the LED load. When the power switch is off, the capacitor acts as a temporary power source, mediating the energy transfer to maintain current flow to the LED load. This intermediary role allows the power switch to be turned off for reduced power consumption while the capacitor bridges the gap to maintain current stability
3Measurement precision
If multiple transistors are used in complex control systems to regulate current, then the current control precision is improved, but the device complexity and power consumption increase
Solution Approach 1:
The patent extracts and eliminates unnecessary transistors from the control system. By using a simplified control circuit that directly controls a single power switch based on input voltage characteristics (rising/falling edges), the design removes the need for complex multi-transistor control arrangements while maintaining adequate current control precision through the capacitor's energy storage and release mechanism
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 reduces power losses and heat in the power switch, improves system efficiency, and maintains constant current to the LED load, balancing power consumption and linear adjustment rate.
Implementation Method 1
a capacitor and an LED load coupled in parallel to receive an output signal of a rectifier circuit
Implementation Method 2
a power switch coupled in series with the LED load, and being configured to control a current path from the rectifier circuit to the LED load
Data Source
AI summary
A power converter for an LED drive circuit, can include: a capacitor and an LED load coupled in parallel to receive an output signal of a rectifier circuit; a power switch coupled in series with the LED load, and being configured to control a current path from the rectifier circuit to the LED load; and a control circuit configured to control the power switch to be turned off in accordance with an error between an output current flowing through the LED load and a desired current value to decrease power consumption of the power switch, where the operation of the power switch is controlled to transition between on and off states in each sinusoidal half-wave period.