Parallel Isolation and Dimming MOS Transistors for LED Backlight Heat Reduction
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Solution Overview
Problem
Conventional LED backlight driving circuits experience high current and heat issues due to the serial connection of dimming and isolation MOS transistors, leading to safety concerns and increased manufacturing costs.
Innovation Solution
The proposed solution involves connecting an isolation MOS transistor and a dimming MOS transistor in parallel, along with resistors and a signal amplification module, to reduce current flow through the isolation MOS transistor, thereby minimizing heat generation and allowing for the use of downgraded MOS transistors to lower costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the isolation MOS transistor and dimming MOS transistor are connected in series, then the circuit can provide isolation and dimming functions, but the current through the isolation MOS transistor becomes excessively high causing heat generation and safety issues
Solution Approach 1:
The patent segments the single transistor function into two separate transistors: an isolation MOS transistor for isolation function and a dimming MOS transistor for dimming function. This segmentation divides the current path and reduces the current burden on the isolation MOS transistor, thereby reducing heat generation and improving circuit safety.
Solution Approach 2:
The patent introduces a dimming MOS transistor as an intermediary component between the control signal and the LED backlight. This intermediary handles the dimming function and current control, preventing excessive current from flowing through the isolation MOS transistor and reducing heat generation.
2Reliability
If high-specification isolation MOS transistors are used to resist high temperature, then circuit safety is improved, but manufacturing cost increases
Solution Approach 1:
By segmenting the transistor functions into isolation and dimming roles, each transistor can be designed with appropriate specifications for its specific function. The isolation MOS transistor does not need to handle high currents, allowing the use of lower-specification, more cost-effective components while maintaining circuit safety.
Solution Approach 2:
The patent changes the operational parameters of the isolation MOS transistor by introducing a separate dimming MOS transistor. This parameter change allows the isolation MOS transistor to operate at lower current levels, enabling the use of lower-specification transistors that are more cost-effective while maintaining reliability.
Data Source
AI summary
The present invention provides an LED backlight driving circuit and an LED backlight driving method. The circuit includes an isolation MOS transistor, a dimming MOS transistor connected in parallel to the isolation MOS transistor, and first and second resistors. The first resistor and the second resistor are connected to each other in parallel and are connected between the dimming MOS transistor and a ground wire. The isolation MOS transistor and the dimming MOS transistor are arranged for electrical connection with an LED light. The LED backlight driving circuit arranges the isolation MOS transistor and the dimming MOS transistor to connect in parallel to each other so as to make the electrical current flowing through the isolation MOS transistor lessened to reduce the amount of heat emitting therefrom and enhance operation safety and also allow the MOS transistor used to be of a downgraded specification to lower down the manufacture cost.