Semiconductor Light Source Circuit Bypass Resistor Power Loss
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Solution Overview
Problem
Existing semiconductor light source lighting circuits experience significant power loss in transistors due to high input voltages, exceeding the transistor's threshold power loss, which can lead to inefficiency and potential damage.
Innovation Solution
Incorporating a bypass resistor in series with the transistor and a current detection resistor, along with a control circuit that adjusts the transistor's operation to minimize power loss by providing a bypass path for the current, allowing the circuit to operate within ranges where power loss is reduced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a transistor is used to control current flowing to the LED, then the LED brightness can be controlled, but the power loss in the transistor increases with higher input voltages
Solution Approach 1:
The current control function is divided between two components: the transistor handles low-voltage precision control (0-5V range) while the PWM controller handles high-voltage switching. This segmentation allows each component to operate in its optimal voltage range, reducing overall power loss.
Solution Approach 2:
A 5V voltage conversion circuit acts as an intermediary between the high-voltage input and the transistor. It converts the high input voltage to a stable 5V supply for the transistor, enabling the transistor to control LED brightness without being directly exposed to high voltages that would cause excessive power loss.
2Power
If the input voltage to the lighting control circuit is increased, then the power delivery capability is improved, but the power loss in the transistor exceeds the threshold
Solution Approach 1:
The system dynamically switches between two operating modes based on power requirements: PWM mode for high-power delivery and transistor control mode for low-power precision control. This dynamic operation allows the system to handle high input voltages without continuously exceeding the transistor's power loss threshold.
Solution Approach 2:
The system changes the operating parameters of the transistor by converting the input voltage to a fixed 5V supply through the voltage conversion circuit. This parameter change isolates the transistor from high-voltage conditions, allowing it to operate reliably within its power loss threshold regardless of the input voltage level.
3Loss of energy
If a bypass circuit is added to reduce transistor power loss, then the energy efficiency is improved, but the device complexity increases
Solution Approach 1:
The voltage conversion circuit serves multiple functions: it converts high input voltage to 5V for the transistor, provides a stable power supply for the control circuitry, and acts as a protective barrier against voltage spikes. This multi-functionality reduces the need for additional separate components, minimizing overall circuit complexity.
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
The solution effectively reduces power loss in the transistor, ensuring it remains below the maximum threshold even at high input voltages, enhancing efficiency and extending the transistor's lifespan.
Implementation Method 1
a bypass resistor RB to configure a bypass path By for the current supplied to the semiconductor light source
Implementation Method 2
a transistor M1 and a current detection resistor RS provided in series in a path of current supplied to a semiconductor light source
Data Source
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AI summary
A semiconductor light source lighting circuit includes a transistor and a current detection resistor provided in series in a semiconductor light source current supply path, a control circuit for controlling the transistor so as to decrease any difference between the voltage occurring at the current detection resistor and a reference voltage, and a bypass resistor to establish a bypass path for the current supplied to the semiconductor light source, where a first end of the bypass path is located at a connection node between the transistor and the semiconductor light source.