DC/DC Converter Drive Unit with Parallel Capacitors
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Solution Overview
Problem
Existing drive units for LEDs and other loads face challenges in accurately controlling brightness at lower levels and in reducing noise and vibration caused by capacitors in DC/DC converters, leading to inefficiencies and increased device size.
Innovation Solution
The implementation of a drive unit with a PWM drive method, soft-start function, and parallel capacitors to smooth alternating-current signals, along with a DC/DC converter that uses parallel input and output capacitors to minimize noise and vibration, enabling precise brightness control and reduced sound production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large capacitance capacitor is used to smooth input voltage or output voltage in a DC/DC converter, then the smoothing effect is improved, but the device size increases and causes expansion/contraction vibrations producing sound
Solution Approach 1:
The patent divides a single large-capacitance capacitor into multiple smaller capacitors connected in parallel. This segmentation maintains the total capacitance value needed for effective voltage smoothing while reducing the physical size of each individual capacitor, thereby minimizing expansion/contraction vibrations and sound production during operation.
2Reliability
If the capacitance of input bypass capacitor or output capacitor is increased to improve smoothing, then the smoothing performance is improved, but the device size and weight increase
Solution Approach 1:
The patent segments the required total capacitance into multiple smaller capacitors connected in parallel. This approach achieves the necessary voltage smoothing performance while using smaller individual capacitor components, thereby reducing both the weight of the capacitors themselves and the overall device weight.
3Device complexity
If a single large capacitor is used to achieve desired capacitance, then the circuit complexity is reduced, but the sound and vibration problems worsen
Solution Approach 1:
The patent divides one large capacitor into multiple smaller capacitors connected in parallel. While this increases the component count slightly, it dramatically reduces sound and vibration issues by minimizing the physical size of each capacitor, thereby reducing expansion/contraction effects during operation.
Solution Approach 2:
The patent combines multiple smaller capacitors in parallel to achieve the equivalent electrical effect of a single large capacitor. This merging approach maintains the desired total capacitance value for proper voltage smoothing while avoiding the vibration and sound problems associated with large individual capacitors.
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
This solution allows for high-accuracy control of LED brightness at low levels, reduces noise and vibration, and minimizes the size of capacitors, enhancing efficiency and longevity of the drive units.
Implementation Method 1
an output capacitor which is an output smoother of the DC/DC converter
Implementation Method 2
an input bypass capacitor which is an input smoother of the DC/DC converter
Data Source
AI summary
A drive unit has a load driving portion driving a load by a PWM drive method; a soft-start function portion for achieving a soft-start function; and a soft-start disabling portion counting a time elapsed after a PWM signal is turned on at start-up of the unit, and disabling the soft-start function when a count value reaches a predetermined value.