Tunable Voltage Regulator for LED Current Regulation
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Solution Overview
Problem
Existing power supply circuits face inefficiencies due to increased minimum bus voltage requirements over time, leading to excessive power dissipation as the circuit ages, necessitating a dynamic solution to maintain the regulated bus voltage at a level that equals or slightly exceeds the instantaneous minimum necessary for constant current regulation in LED circuits.
Innovation Solution
A tunable voltage regulator system with a control circuit that senses voltages at both nodes and adjusts the variable bus voltage by generating a trimming signal to ensure the voltage remains above the minimum required for current regulation, minimizing power dissipation by operating just above the knee point where current regulation fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fixed regulated bus voltage is set higher than the anticipated minimum voltage range, then the circuit can maintain reliable current regulation throughout its life, but excessive power dissipation occurs
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed regulated bus voltage to a dynamically adjustable bus voltage. The control circuit continuously monitors the voltage across the current regulating circuit and adjusts the bus voltage upward only when necessary to maintain current regulation, rather than maintaining a statically high voltage throughout the circuit's life. This resolves the contradiction by making the voltage adaptive to actual operating conditions.
Solution Approach 2:
The patent changes the parameter of bus voltage from a fixed value to a variable value that can be adjusted based on circuit conditions. The control circuit modifies the bus voltage parameter dynamically based on feedback from voltage sensing, allowing the system to operate at the minimum necessary voltage while maintaining reliability when needed.
2Loss of energy
If the bus voltage is reduced to minimize power dissipation, then energy efficiency improves, but the current regulating circuit may fail to regulate current properly
Solution Approach 1:
The patent implements feedback by having the control circuit continuously sense the voltage across the current regulating circuit and use this information to adjust the bus voltage. This feedback mechanism ensures that the bus voltage is increased only when the sensing indicates that current regulation is at risk, thereby maintaining reliability while minimizing power dissipation during normal operation.
Solution Approach 2:
The system performs self-service by automatically adjusting its own bus voltage based on internal sensing of the current regulating circuit's performance. The control circuit monitors the voltage drop across the regulating circuit and autonomously decides when to increase the bus voltage to maintain proper current regulation without external intervention.
3Reliability
If a fixed high bus voltage is used, then current regulation is maintained throughout circuit life, but power dissipation increases excessively
Solution Approach 1:
The patent transforms the static fixed high voltage approach into a dynamic system where the bus voltage adjusts in real-time based on actual circuit needs. The control circuit enables the voltage to be high only when necessary for current regulation, rather than maintaining it at a high fixed level throughout the circuit's operational life.
Solution Approach 2:
The patent changes the bus voltage parameter from a fixed high value to a variable value that adapts to circuit conditions. This parameter change allows the system to operate efficiently at lower voltages while maintaining the capability to increase voltage when current regulation requires it.
Data Source
AI summary
A tunable voltage regulator has an output generating a variable voltage and an input that receives a trimming signal for controlling the output variable voltage. A current regulating circuit operates to regulate a current flowing through a load in response to the variable voltage. A control circuit senses the variable voltage and a drop voltage of the current regulating circuit, and determines whether the current regulating circuit has failed to regulate the current flowing through the load because the variable voltage is too low. In response thereto, the control circuit generates the trimming signal to set the variable voltage to a value sufficient for the current regulating circuit to successfully regulate the current flowing through the load.