Reference Voltage Regulating Circuit for LED Constant Current Driver
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Solution Overview
Problem
Conventional constant current sources for LED drivers face challenges in maintaining stable output current and minimizing power losses, as the output voltage often needs to be higher than a threshold voltage, leading to inefficiencies when the ideal output current or equivalent resistor varies.
Innovation Solution
A reference voltage regulating method and circuit that sets a proportion between the first resistor and ideal equivalent resistor, and between the first current and ideal output current, ensuring the reference voltage is slightly higher than the threshold voltage, thereby maintaining a stable constant current source operation and improving system efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the output voltage is set higher than the threshold voltage to maintain stable constant current operation, then the reliability of constant current output is improved, but the power losses increase and system efficiency deteriorates
Solution Approach 1:
The reference voltage is made dynamically adjustable through a capacitor connected to the reference voltage terminal. The capacitor charges or discharges to modify the reference voltage level, allowing the system to adapt the output voltage to the minimum required threshold rather than maintaining a fixed high voltage, thus reducing power losses while ensuring stable operation
Solution Approach 2:
The system changes the reference voltage parameter dynamically based on operational requirements. By adjusting the reference voltage terminal through capacitor charging/discharging, the output voltage is optimized to be just above the threshold voltage needed for stable constant current operation, rather than maintaining a consistently high voltage level, thereby minimizing energy losses
2Adaptability or versatility
If the reference voltage is set significantly higher than the threshold voltage to ensure stable operation under varying conditions, then the adaptability to current variations is improved, but the system efficiency deteriorates due to increased power losses
Solution Approach 1:
The system employs feedback through the capacitor connected to the reference voltage terminal. When output current varies, the capacitor charges or discharges to adjust the reference voltage accordingly, providing adaptive response to current variations. This feedback mechanism ensures stable operation under varying conditions while maintaining the reference voltage at the minimum necessary level, thus preserving system efficiency
Data Source
AI summary
The present invention relates to reference voltage regulating methods and circuits for a constant current driver. In one embodiment, a method can include: setting a reference voltage circuit matching with a current output channel of a constant current source; setting a first resistor of the reference voltage circuit to follow an ideal equivalent resistor of the current output channel, and maintaining a proportion of the first resistor and the ideal equivalent resistor to be no less than a predetermined value M; setting a first current of the reference voltage circuit to follow an ideal output current of the current output channel, and maintaining a proportion of the first current and the ideal output current to be no less than 1/M; and setting a product of the first current and the first resistor to be a reference voltage of the reference voltage circuit.