Microcontroller Internal Voltage Divider for LED Current Control
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Solution Overview
Problem
Existing circuit arrangements for operating LEDs with controllable constant current sources are inefficient due to the need for digital potentiometers, which increase complexity and introduce time delays in adjusting current levels.
Innovation Solution
The use of a microcontroller with digital-to-analog functionality to generate an analog voltage signal, utilizing internal voltage divider components as a variable resistor to control the constant current source, eliminating the need for digital potentiometers and enabling rapid adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a digital potentiometer is used to control the constant current source, then the current level can be adjusted during operation, but the device complexity increases and response time is delayed
Solution Approach 1:
The invention extracts the resistance control function from an external digital potentiometer and relocates it to the microcontroller's internal voltage divider components. This eliminates the need for a separate digital potentiometer component while maintaining the ability to adjust current levels through software control of the DAC output.
Solution Approach 2:
The microcontroller's internal voltage divider components, originally designed for DAC functionality, are made multi-functional by using them also as a variable resistor for controlling the constant current source. This universal usage eliminates the need for dedicated external control components.
2Adaptability or versatility
If a digital potentiometer is used to control the constant current source, then the current level can be adjusted during operation, but the response time is delayed due to conversion requirements
Solution Approach 1:
The invention removes the time-consuming digital-to-analog conversion step that occurs in external digital potentiometers by using the microcontroller's existing DAC output directly to control the resistance. The voltage divider components provide immediate resistance changes without additional conversion delays.
3Device complexity
If the resistance is permanently fixed to set the current flow, then the circuit is simple, but the current level cannot be adjusted during operation
Solution Approach 1:
The invention transforms the static, fixed resistance into a dynamic, software-controllable resistance by using the microcontroller's DAC output to vary the effective resistance value. This allows the circuit to maintain simplicity while gaining the ability to adjust current levels dynamically during operation.
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 simplifies and accelerates the control of constant current sources, allowing for efficient and immediate adjustments to current levels without the delays associated with digital potentiometers, thereby optimizing LED operation.
Implementation Method 1
internal voltage divider components of the microcontroller form an internal resistance which is part of the resistance used to control the constant current source
Data Source
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AI summary
A circuit arrangement for operating light sources (100) has a controllable constant current source (50) which, depending on a resistor connected to a control terminal (53) of the constant current source (50), sets a current (ILED) intended for operating the light sources (100), wherein the circuit arrangement further includes a microcontroller (10) with digital-to-analog functionality and the control terminal (53) of the constant current source (50) is connected to a DAC terminal (11) of the microcontroller (10), such that internal voltage divider components of the microcontroller (10) form an internal resistor (20) which is part of the resistor used to control the constant current source (50).