LED Driver Standby Pre-Charging for Fast Light Startup
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Solution Overview
Problem
Existing LED driving circuits face issues with long delays when switching from standby mode to minimum light emitting level and high standby power consumption, particularly in linear driving circuits.
Innovation Solution
A driving circuit that linearly charges an output capacitor directly from the mains supply in standby mode, with the output voltage set below the LED's turn-on voltage but above a preset lowest voltage, allowing quick charging when switching to illumination mode and reducing power consumption by controlling the linear current source to operate only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a linear driving circuit is used to drive LED loads, then the structure is simple and cost is low, but the delay from standby mode to minimum light emitting level is long and standby power consumption is high
Solution Approach 1:
The patent applies preliminary action by pre-charging the output capacitor to a voltage level close to the LED turn-on voltage during standby mode through linear charging from mains supply. This preliminary charging action ensures that when the illumination mode is activated, the capacitor is already near the required voltage threshold, significantly reducing the delay time to reach minimum light emitting level while maintaining simple linear circuit structure
Solution Approach 2:
The patent implements dynamics by dynamically adjusting the charging current to the output capacitor based on the detected voltage level. The circuit transitions from a static charging approach to a dynamic one where the charging current is modulated to maintain the capacitor voltage within an optimal range, enabling fast response when switching from standby to illumination mode while managing power consumption effectively
2Loss of time
If a linear driving circuit charges the output capacitor from mains supply in standby mode, then the delay to minimum light emitting level is reduced, but standby power consumption increases
Solution Approach 1:
The patent applies partial action by charging the output capacitor only to a voltage level sufficient for fast startup (close to but not exceeding the LED turn-on voltage) during standby mode, rather than fully charging it. This partial charging approach reduces unnecessary energy consumption while still achieving the goal of minimizing delay when transitioning to illumination mode
Solution Approach 2:
The patent implements feedback by continuously detecting the voltage across the output capacitor and using this information to control the charging current. The feedback mechanism ensures that the capacitor is charged to the optimal voltage level for fast startup without overcharging, thereby minimizing standby power consumption while maintaining rapid response capability when illumination is required
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 significantly reduces the delay in switching to minimum light emitting level and decreases standby power consumption by optimizing the charging mechanism and operational states of the driving circuit.
Implementation Method 1
an output capacitor (C1) connected in parallel with the LED load
Implementation Method 2
the capacitor is connected to the mains supply via a linear driver and is charged by the mains with its frequency
Data Source
Figure 1
Figure 2~3
AI summary
Embodiments of the present disclosure provide a driving circuit and a lamp comprising the same. The driving circuit comprises inputs connected to a mains supply; outputs connected to an LED load; an output capacitor connected in parallel with the LED load; an LED driving current source connected to the outputs, and configured to convert the mains supply at the inputs to current at the outputs in an illumination mode, such that the current flows through the LED load and charges the output capacitor; and a control circuit configured to receive a standby signal to enable a standby mode, and to control the mains supply to linearly charge the output capacitor in the standby mode, such that an output voltage at the output can be lower than a turn-on voltage of the LED load and is higher than a preset lowest voltage. With the driving circuit, it is advantageous to reduce the delay from the standby mode to a minimum light emitting level, and meanwhile a lower power loss can be realized by linearly charging the output capacitor through the mains supply.