Backlight Driving Apparatus Current Mirror Circuit
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Solution Overview
Problem
Existing backlight driving apparatuses for LED arrays are complex in circuit configuration and lack uniformity in current balance, requiring multiple power sources and controllers, which increases cost and complexity.
Innovation Solution
A backlight driving apparatus that uses a power source and current generator with a current mirror circuit to ensure uniform current distribution across multiple LED arrays, simplifying the circuit configuration and using choke coils and mirror transistors to equalize current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple power sources and controllers are used to drive multiple LED arrays, then each LED array can be driven independently, but the circuit configuration becomes complex and cost increases
Solution Approach 1:
The patent combines multiple power sources into a single shared power source that supplies current to all LED arrays through a current generator. The current generator produces multiple currents from one input current, and a current mirror circuit distributes these currents to multiple LED arrays. This merging approach eliminates the need for separate power sources and controllers for each LED array, thereby simplifying the circuit configuration while maintaining independent driving capability through current control.
Solution Approach 2:
The current generator serves multiple functions: it receives a single input current from the power source and generates multiple output currents to drive multiple LED arrays simultaneously. The current mirror circuit further enhances this universality by automatically balancing the currents across all LED arrays. This multi-functional design allows one component to replace what would traditionally require multiple separate components, reducing circuit complexity.
2Ease of operation
If multiple power sources are used to drive multiple LED arrays, then each array can be controlled separately, but the current balance among arrays becomes non-uniform
Solution Approach 1:
The current mirror circuit implements a feedback mechanism that automatically monitors and balances the currents flowing through multiple LED arrays. By using mirror transistors that replicate the current from a reference LED array, the circuit ensures that all LED arrays receive uniform current despite variations in LED characteristics or aging. This feedback-based current balancing maintains manufacturing precision while allowing separate control of each array through the current generator.
Solution Approach 2:
The current mirror circuit creates equipotential conditions across all LED arrays by ensuring that the voltage and current conditions are identical for each array. The mirror transistors are configured to maintain equal voltage drops across corresponding LEDs in different arrays, thereby achieving uniform current distribution. This equipotential approach ensures precise current balance while preserving the ability to independently control each array's operation.
3Device complexity
If a single power source is used with a current generator, then circuit configuration is simplified, but achieving uniform current distribution across LED arrays becomes difficult
Solution Approach 1:
The current mirror circuit acts as an intermediary between the current generator and the LED arrays. It receives the generated currents and automatically balances them before distributing to each LED array. The mirror transistors serve as mediators that transfer and equalize the current levels, ensuring uniformity without requiring complex control circuits. This intermediary function resolves the contradiction by maintaining current uniformity while preserving the simplicity of the single power source configuration.
Solution Approach 2:
The current mirror circuit uses the current from a reference LED array as a template to replicate and distribute to other LED arrays. By copying the current characteristics from one array to others through mirror transistors, the system ensures that all arrays receive identical current levels. This copying mechanism achieves precise current uniformity while maintaining the simplicity of the overall circuit configuration with a single power source.
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 solution simplifies the circuit configuration and achieves uniform current balance across LED arrays, reducing the need for multiple power sources and controllers, thereby lowering costs and enhancing efficiency.
Implementation Method 1
a current mirror circuit for allowing the same amount of currents to flow respectively through the light emitting diode arrays based on current from any one of the n light emitting diode arrays
Implementation Method 2
a current generator for generating currents to drive the light emitting diode arrays using the driving current, respectively
Data Source
AI summary
A backlight driving apparatus is disclosed which is capable of simplifying a circuit configuration for driving of a plurality of light emitting diode arrays and making the current balance of the light emitting diode arrays uniform. The backlight driving apparatus includes n light emitting diode arrays that include a plurality of light emitting diodes connected in series, a power source for generating a driving current, a current generator for generating currents to drive the light emitting diode arrays using the driving current, respectively, and a current mirror circuit for allowing substantially the same amount of currents to flow respectively through the light emitting diode arrays based on current from any one of the n light emitting diode arrays.