LED Driving Circuit with Dynamic Current Adjustment for Battery Life Extension
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Solution Overview
Problem
Conventional LED flashlights with DC-DC converter circuits face reduced battery life due to increased internal battery resistance over time, which necessitates maintaining a constant driving current, thereby shortening the battery service life.
Innovation Solution
A driving circuit comprising a boost converter circuit, control circuit, current switch, and series-connected resistors that adjust the duty cycle of the control signal based on the sense voltage to reduce the driving current as battery voltage decreases, incorporating a boost converter circuit with a diode, inductor, and control switch, and a control circuit with a reference, oscillator, PWM, and digital logic circuits to manage the driving current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a DC-DC converter circuit maintains constant driving current, then light emission performance is preserved, but battery service life is shortened
Solution Approach 1:
The patent applies dynamics by transitioning from a static constant current mode to a dynamic current adjustment mode. The control circuit continuously monitors battery voltage and adjusts the driving current accordingly, allowing the system to adapt to changing battery conditions. This resolves the contradiction by making the driving current variable rather than fixed, extending battery life while maintaining adequate light emission performance throughout the battery discharge cycle.
Solution Approach 2:
The patent changes the parameter of driving current from a constant value to a variable value that changes with battery voltage. By establishing a relationship where driving current decreases as battery voltage decreases, the system optimizes power consumption at different battery states. This parameter change resolves the contradiction between maintaining light emission performance and extending battery service life.
2Reliability
If internal battery resistance increases over time, then battery voltage decreases, but constant driving current requirement aggravates battery depletion
Solution Approach 1:
The patent implements feedback by having the control circuit continuously monitor battery voltage and use this information to adjust the driving current. The feedback loop detects changes in battery conditions (including increasing internal resistance) and responds by modifying the driving current to optimize power consumption. This feedback mechanism resolves the contradiction by preventing excessive current draw when battery voltage is low, thereby extending battery service life while maintaining reliable operation.
Solution Approach 2:
The system transitions from a static constant current approach to a dynamic current adjustment approach based on real-time battery voltage monitoring. This dynamic adaptation allows the system to respond to increasing battery internal resistance by reducing driving current when necessary, resolving the contradiction between maintaining driving current stability and extending battery service life.
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
The solution prolongs battery life by gradually reducing the driving current and output voltage as battery voltage decreases, thereby extending the service life of the batteries.
Implementation Method 1
the boost converter circuit (1) receives a DC (direct-current) source voltage (VCC) and a control signal, and converts the source voltage into a DC output voltage higher than the source voltage (VCC) according to the control signal
Implementation Method 2
providing a driving current for driving light emission of the LED (D1)
Data Source
Figure 1
AI summary
A driving circuit includes a control circuit (2) and a boost converter circuit (1). The control circuit (2) receives a sense voltage (SENS) associated with a direct-current (DC) source voltage (VCC), and generates a control signal with a duty cycle that varies with the sense voltage (SENS) in a monotonically increasing manner. The boost converter circuit (1) receives the DC source voltage (VCC) and the control signal, thereby providing a driving current for driving light emission of a light emitting component (D1). The driving current has a magnitude positively correlated to the duty cycle of the control signal.