LED Driving Apparatus with Single Current Detection Transistor
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Solution Overview
Problem
Existing LED driving circuits face challenges in efficiently driving LEDs with AC power while maintaining reliability and noise resistance, particularly due to the complexity of circuit design and activation timing precision, which affects power supply efficiency and LED operation.
Innovation Solution
A simplified LED driving apparatus using a rectifying circuit, LED portions, bypass portions, and a current control portion that detects current and adjusts operation based on rectified voltage, allowing common control signals to manage bypass operations and reduce noise, thereby stabilizing the circuit and improving power factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple current detection transistors are used to control LED blocks, then LED current control precision is improved, but device complexity and parts count increase
Solution Approach 1:
The patent combines multiple current detection functions into a single current detection transistor that detects the total current flowing through all LED blocks. This single transistor replaces what would traditionally require multiple transistors, simplifying the circuit while maintaining control precision through unified current monitoring.
Solution Approach 2:
The single current detection transistor serves multiple functions: it detects current for all LED blocks simultaneously, provides a unified control signal for multiple bypass circuits, and enables centralized control of the entire LED array. This multi-functional approach reduces parts count while maintaining comprehensive control capability.
2Ease of operation
If multiple current detection transistors are independently activated, then individual LED block control is improved, but noise sensitivity and reliability worsen due to precise activation timing requirements
Solution Approach 1:
The patent merges multiple independent current detection transistors into a single current detection transistor. This unified detection approach eliminates the need for precise synchronization between multiple independently activated transistors, reducing noise sensitivity and improving reliability while maintaining the ability to control individual LED blocks through bypass circuits.
3Adaptability or versatility
If AC power supply is used for LED driving, then power supply versatility is improved, but current control stability worsens due to voltage variations
Solution Approach 1:
The patent implements a feedback control mechanism where the single current detection transistor continuously monitors the total current flowing through the LED blocks. Based on this real-time detection, the control circuit adjusts the bypass circuit configurations to maintain stable current control despite AC voltage variations, ensuring consistent LED operation across different power conditions.
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 enables reliable and efficient LED driving with improved noise resistance and power factor, suppressing harmonic components and ensuring stable light output by controlling current flow proportionally to AC input voltage.
Implementation Method 1
a rectifying circuit 2, and obtains a rectified voltage by rectifying an AC voltage
Implementation Method 2
a first bypass portion 21 connected in series to the first LED portion 11 and in parallel to a second LED portion 12
Implementation Method 3
a first charging/discharging capacitor 111 connected in parallel to the in-series connection of the first and second LED portions
Data Source
AI summary
An apparatus includes first and fourth bypasses, a current detector, and a current controller. The first bypass is connected serially to a first LED, and controls the current amount in the first LED. The fourth bypass is connected serially to a second LED, and controls the current amount in the first and second LEDs. The detector detects current detection signal based on the current amount on an output line along which the first and second LEDs are connected serially to each other. The controller provides control signal for controlling the first and fourth bypasses based on the detection signal. The controller includes one output for providing the control signal. The first and fourth bypasses are connected in parallel to the one output.