DC-DC Converter Continuous Current Mode Control
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Solution Overview
Problem
Existing power supply devices for semiconductor light sources, such as LEDs, face challenges in managing current ripples and noise due to their low-impedance nature, which affects efficiency and noise levels, especially when used in various load configurations.
Innovation Solution
A power supply device with a DC-DC converter and a controller that regulates the timing of the switching element's operation to maintain a continuous current mode, using a flyback converter and a drive frequency setter to determine the frequency for driving the switching element, ensuring the current supplied to the load has a small ripple component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a DC-DC converter operates in current boundary mode to reduce loss, then energy efficiency is improved, but current ripple increases significantly
Solution Approach 1:
The patent applies dynamics by transitioning from a static operating mode (current boundary mode) to a dynamic continuous conduction mode where the switching element operates continuously. The controller dynamically adjusts the switching timing to maintain continuous current flow through the inductance element, ensuring the current never reaches zero, thus maintaining continuous operation while reducing ripple.
Solution Approach 2:
The patent implements continuity of useful action by ensuring the current through the inductance element never discontinues. The controller regulates the switching element Q1 to maintain continuous current mode operation, where energy transfer from the inductance element to the load is continuous rather than intermittent, eliminating the zero-current periods that cause large ripples in boundary mode operation.
2Object-generated harmful factors
If switching frequency is increased to reduce current ripple, then current ripple is reduced, but device complexity and loss increase
Solution Approach 1:
The patent applies feedback by using a current detection circuit to monitor the actual current through the inductance element and feeding this information back to the controller. The controller compares the detected current with the target current value and adjusts the switching element's ON/OFF timing accordingly, creating a closed-loop control system that maintains continuous conduction mode without requiring excessively high switching frequencies.
3Manufacturing precision
If semiconductor light source loads are standardized, then manufacturing precision is improved, but adaptability decreases
Solution Approach 1:
The patent applies universality by designing a power supply device that can handle multiple load configurations through standardized interface circuits. The system uses a universal controller that can adapt to different LED load arrangements (series, parallel, or combinations) by receiving current detection signals from standardized detection circuits, allowing one power supply design to serve multiple loading scenarios without requiring custom designs for each configuration.
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 provides a power supply device capable of efficiently handling various semiconductor light source loads with reduced current ripples and noise, enhancing efficiency and functionality while being cost-effective for vehicle lamp fittings.
Implementation Method 1
a DC-DC converter (1) having an inductance element (T1) and a switching element (Q1); the DC-DC converter (1) performs voltage conversion by storing energy in the inductance element (T1) from an input power source (E) when the switching element (Q1) is on, and discharging the energy, which is stored in the inductance element (T1), to a load (2) side when the switching element (Q1) is off
Data Source
AI summary
Provided is a power supply device, which is capable of coping with semiconductor light source loads to be set in various ways, and has high efficiency, in which a current to be supplied to each of the loads has a small ripple. The power supply device supplies power to a semiconductor light source load and lights the semiconductor light source load, and includes: a DC-DC converter; and a controller. The DC-DC converter includes an inductance element and a switching element, and performs voltage conversion by storing energy in the inductance element from an input power source when the switching element is on, and discharging the energy, the energy being stored in the inductance element, to a load side when the switching element is off. The controller controls ON/OFF operations of the switching element so that an output current of the DC-DC converter can be the same as a target value. In the power supply device, means for regulating timing of turning on the switching element so that a current flowing through the inductance element can flow in a continuous mode operation is provided at least in the controller.