Charge Control Device for EDLCs Using Switching Regulator Feedback
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Solution Overview
Problem
Conventional charge circuits for electric double-layer capacitors (EDLCs) in drive recorders face challenges in rapid charging due to high heat generation and large circuit losses, especially in linear regulation types, and lack a general-purpose IC for switching-type constant current control, which is necessary for quick and efficient charging.
Innovation Solution
A charge control device with a switching regulator that includes a feedback unit and a control unit to manage the charge current, using a general-purpose current mode switching regulator with voltage dividing resistances to achieve constant current control, reducing harmonic oscillations and enabling quick charging of EDLCs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a linear regulation type charge circuit is used, then the circuit is simple to implement, but heat generation is high and circuit loss is large
Solution Approach 1:
The patent replaces the linear regulation type charge circuit with a switching type charge circuit. This substitution transforms the charging mechanism from a continuous analog regulation system to a discrete switching system, enabling efficient constant current control through PWM (pulse width modulation) techniques. The switching circuit uses MOSFETs or similar switching elements to rapidly switch between on and off states, achieving precise current control while minimizing power dissipation.
2Loss of energy
If a switching type charge circuit is used, then circuit loss is reduced, but a dedicated IC development is required which increases device complexity
Solution Approach 1:
The patent employs a switching type charge circuit that can function as a universal constant current source for charging EDLCs. The circuit design integrates multiple functions including current sensing, PWM control, and protection mechanisms into a single switching regulator architecture. This multi-functional approach eliminates the need for dedicated specialized ICs while maintaining efficient constant current control capabilities.
3Productivity
If fast charging is implemented without constant current control, then charging speed increases, but harmonic oscillation occurs reducing reliability
Solution Approach 1:
The patent implements a feedback control mechanism where the charge current is continuously monitored and compared against a reference value. The difference signal is amplified and used to adjust the PWM duty cycle in real-time, maintaining constant current flow during the charging process. This closed-loop feedback system prevents harmonic oscillations while enabling rapid charging by optimizing the switching frequency and duty cycle.
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 allows for efficient and rapid charging of EDLCs by controlling the charge current to a constant value, reducing circuit losses and heat generation, and is applicable to various onboard apparatuses, including drive recorders, while minimizing size and cost.
Implementation Method 1
a switching regulator for charging a capacitor with electricity supplied from a power supply
Implementation Method 2
feedback unit that feedback-inputs a predetermined control amount into the switching regulator, and control unit included in the switching regulator, the control unit controlling a charge current supplied to the capacitor in accordance with the control amount feedback-input from the feedback unit
Data Source
AI summary
A charge control device includes a switching regulator that charges a capacitor with electricity supplied from a power supply. The charge control device is characterized in that feedback unit that feedback-inputs a predetermined control amount to the switching regulator is provided, and the switching regulator includes a control unit that controls a charge current supplied to the capacitor in accordance with the control amount feedback-input from the feedback unit.