LED Driver Circuit Reducing Switch-On Delay With Diode Bypass
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Solution Overview
Problem
Existing light emitting diode (LED) circuit driving technologies require additional switches to prevent capacitor discharge, which are complex, expensive, and require control, leading to increased complexity and cost.
Innovation Solution
The use of diodes instead of switches to prevent capacitor discharge in conducting mode, simplifying the apparatus and eliminating the need for additional control, with diodes connected to terminals and switches configured to bypass LED circuits, allowing for independent color temperature and dimming control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an additional switch is used to prevent capacitor discharge via the first switch, then the capacitor discharge prevention is achieved, but the device complexity and cost increase
Solution Approach 1:
A second diode is introduced as an intermediary component to prevent capacitor discharge through the first switch. The second diode is connected in parallel with the first switch, with its anode connected to the switch's input terminal and cathode to the output terminal. When the first switch conducts, the second diode blocks reverse current flow that would otherwise discharge the capacitor, thereby preventing discharge without requiring additional active control elements.
Solution Approach 2:
The patent replaces complex controllable switches with simple passive diodes for the discharge prevention function. Diodes are cheaper, more reliable, and require no control signals compared to additional switches. The second diode provides the necessary protection function indefinitely without degradation or control requirements, eliminating the complexity of switch coordination.
2Reliability
If an additional switch is used to prevent capacitor discharge, then the capacitor discharge prevention is achieved, but the manufacturing cost increases
Solution Approach 1:
The patent substitutes expensive controllable switches with inexpensive passive diodes for the discharge prevention function. Diodes are among the cheapest semiconductor components, requiring no control circuitry, drivers, or synchronization logic. The second diode provides robust discharge protection at minimal cost, significantly reducing the bill of materials compared to additional switch implementations.
3Ease of operation
If switches are used to bypass LED circuits, then the switching function is achieved, but the switch-on delay increases
Solution Approach 1:
The first capacitor is pre-charged through the first switch during normal operation. When bypass mode is activated, the pre-charged capacitor immediately supplies current to the LED circuit without waiting for switch closure. This preliminary energy storage eliminates switch-on delay, as the capacitor acts as an instantaneous energy source upon activation.
Solution Approach 2:
The first capacitor serves as an intermediary energy storage element between the power source and the LED circuit. During bypass operation, the capacitor directly supplies current to the LED circuit without requiring the main switch to close, thereby eliminating the switch-on delay associated with inductive circuits or complex switch arrangements.
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 reduces switch-on delay without additional switches, resulting in a simpler, cheaper, and more robust LED circuit driving apparatus that can control color temperature and dimming modes independently.
Implementation Method 1
a first diode for, in the first conducting mode, preventing the first capacitor from being discharged via the first switch
Implementation Method 2
a first light emitting diode circuit to be connected to a current source
Data Source
Figure 1
Figure 2
AI summary
An apparatus for driving a light emitting diode circuit (1) comprises first and second terminals (11,12) to be connected to the light emitting diode circuit (1), a capacitor (31) connected to the first and second terminals (11,12), a switch (41) for,in a conducting mode,bypassing the light emitting diode circuit (1), and a diode (51) for,in the conducting mode,preventing the capacitor (31)from being discharged via the switch (41). In this way, a reduced switch-on delay is realized without an additional switch being required for activating and deactivating said capacitor (31). The diode (51) is simpler and cheaper and more robust than such an additional switch and does not require a control. Preferably, the apparatus comprises a further terminal(13),wherein the diode (51) is connected to the further terminal (13) and to one of the first and second terminals (11,12),and the switch (41) is connected to the further terminal (13) and to the other one of the first and second terminals (11,12).