Lighting Power Control Circuit Inductor Capacitor Charging
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Solution Overview
Problem
Portable lighting devices face challenges in implementing switches remotely from the power source, leading to weight and bulk issues due to conductive sleeves or mechanical switch failures under high current conditions.
Innovation Solution
A power control circuit with an inductor and power transistor, where capacitors are periodically charged by voltage spikes to keep the transistor on, allowing high current operation without passing currents through the mechanical switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive sleeve is added to accommodate circuit paths between the tailcap switch and head end components, then the electrical connection is improved, but the weight and bulk of the flashlight increase
Solution Approach 1:
The patent extracts the high current carrying function from the mechanical switch and places it in a separate power transistor located in the head end electronics. This allows the mechanical switch to be lightweight and positioned remotely in the tailcap, while the power transistor handles the high currents near the light source, eliminating the need for heavy conductive sleeves.
Solution Approach 2:
The patent introduces a power transistor as an intermediary component between the mechanical switch and the light source. The mechanical switch controls a control signal that activates the power transistor, which then handles the high current delivery to the LED. This intermediary allows the mechanical switch to remain lightweight and remotely positioned without requiring heavy current-carrying conductors.
2Device complexity
If a mechanical switch is used to provide the ground path for the light source, then the device complexity is reduced, but the switch fails under high current conditions
Solution Approach 1:
The patent replaces the mechanical switch's high current carrying function with an electronic power transistor. The mechanical switch retains only its low-current control function, while the power transistor handles the high current delivery to the light source. This substitution allows the mechanical switch to operate reliably without being subjected to high currents that would cause failure.
Solution Approach 2:
The patent segments the switch function into two separate components: a mechanical switch for control signaling and a power transistor for high current delivery. This segmentation allows each component to be optimized for its specific function - the mechanical switch for reliable actuation and the power transistor for high current handling - thereby improving overall system reliability.
3Reliability
If mechanical switches capable of sustaining high currents are used, then the reliability is improved, but the weight and cost increase and user force requirements increase
Solution Approach 1:
The patent replaces the need for heavy-duty mechanical switches with a combination of a lightweight mechanical switch and an electronic power transistor. The mechanical switch only needs to handle control signals, allowing it to be lightweight and easy to actuate, while the power transistor handles the high current delivery, providing the necessary reliability without the weight and force requirements of a heavy mechanical switch.
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 enables reliable high current operation without mechanical switch failure, reducing weight and bulk, and allowing for efficient control of high power light sources using a small mechanical switch.
Implementation Method 1
an inductor, a power transistor configured to pass an operating current associated with the light source, and one or more capacitors configured to keep the power transistor turned on to pass the operating current, wherein the one or more capacitors are configured to be periodically charged in response to a voltage spike generated across the inductor
Data Source
AI summary
A lighting device power control circuit configured to charge one or more capacitors through the pulsing of an inductor is provided. In one example, a lighting device includes a light source and a power control circuit. The power control circuit comprises an inductor, a power transistor configured to pass an operating current associated with the light source, and one or more capacitors configured to keep the power transistor turned on to pass the operating current. The one or more capacitors are configured to be periodically charged in response to a voltage spike generated across the inductor. Related methods and additional embodiments are also provided.