Switching Regulator Afterglow Suppression via Capacitor Discharge
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Solution Overview
Problem
Existing switching regulators for light sources, such as LEDs, often experience undesirable afterglow effects due to stored charge, which are difficult to control and can vary with different lamp colors and power levels, leading to inconsistent results when switching off.
Innovation Solution
A switching regulator with a control circuit that drives a second switch to discharge a capacitor, replacing the diode in step-down or step-up converters, allowing for controlled afterglow reduction by managing the discharge via a resistor or potential isolation switches, ensuring efficient disconnection from ground potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a capacitor is used for voltage stabilization in the switching regulator, then voltage stability is improved, but afterglow effect occurs due to stored charge
Solution Approach 1:
A discharge switch is introduced as an intermediary component between the capacitor and the light source circuit. This switch acts as a mediator that can redirect the stored charge from the capacitor away from the light source during the off-state, preventing afterglow while maintaining voltage stability during operation. The discharge switch enables controlled discharge paths without affecting the normal voltage stabilization function.
2Object-generated harmful factors
If the stored charge in the capacitor is reduced by current flow through the light source to suppress afterglow, then afterglow is reduced, but the light source power consumption increases and control precision is lost
Solution Approach 1:
The current path is segmented into two separate paths: one through the light source for normal operation control, and another through the discharge switch for capacitor discharge. This segmentation allows independent control of each function - the light source current can be precisely controlled for dimming and operation, while the discharge switch handles capacitor charge removal separately, preventing interference with light source control precision.
3Adaptability or versatility
If different lamps of different color and power are switched off simultaneously, then the operating device can handle various lamp types, but afterglow effects vary and become difficult to control
Solution Approach 1:
The discharge switch is controlled based on detection of the light source off-state, creating a self-adjusting discharge mechanism. When any light source is switched off, the control circuit detects this state and automatically activates the discharge switch to discharge the capacitor, regardless of the specific lamp type, color, or power rating. This self-service approach eliminates the need for complex manual control adjustments for different lamp configurations.
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 effectively reduces afterglow effects by controlled discharging and potential isolation, providing a simple and cost-effective method to manage afterglow across various LED configurations and power levels.
Implementation Method 1
a capacitor connected in parallel with the light-emitting diode for voltage stabilization. The charge contained in this smoothing capacitor/filter capacitor can cause the light source or light-emitting diode to glow or glow after the switching regulator has been switched off
Implementation Method 2
a second switch coupled to the capacitor for discharging the capacitor. The control circuit is designed to at least partially discharge the capacitor by driving the second switch when the operation of the light-emitting diode is terminated
Data Source
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AI summary
The present invention relates to a switching regulator for at least one light source (6) comprising a control circuit (7) designed to actuate a first switch (S1) of the switching regulator (1) coupled to a coil (L), a capacitor (C) coupled to the coil (L) to which the light source (6) is connected or can be connected, and a second switch (S2) coupled to the capacitor (C) for discharging the capacitor (C). The control circuit (7) is designed to at least partially discharge the capacitor (C) when the operation of the light source (6) ceases by actuating the second switch (S2) in order to suppress afterglow.