Hysteretic DC-DC Converter for Multi-Channel LED Drivers
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Solution Overview
Problem
Existing LED driver circuits face complexity in supporting varied numbers of LEDs and dimming duty cycles across channels, complicating the design of DC-DC converters and converter control circuitry, as they struggle to maintain regulated voltage levels efficiently while minimizing power consumption.
Innovation Solution
A control circuit for DC-DC converters that includes a duty cycle control unit responsive to feedback, enabling and disabling based on threshold voltages to maintain output voltage within a narrow range, and a method to track the dominant LED channel dynamically, allowing for independent dimming and current control across channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If LED driver circuits support varied numbers of LEDs and different dimming duty cycles across channels, then illumination functionality and adaptability are improved, but device complexity increases
Solution Approach 1:
The patent divides the control of multiple LED channels into segments by identifying a dominant channel that requires the highest voltage and controlling it separately from other channels. This segmentation allows the DC-DC converter to be optimized for the dominant channel while other channels are controlled independently, reducing overall system complexity despite supporting varied illumination requirements.
Solution Approach 2:
The patent implements dynamic control by enabling the DC-DC converter only during specific time periods when the dominant LED channel is active. The converter is dynamically enabled and disabled based on the operational state of the dominant channel, allowing the system to adapt to varying illumination requirements while simplifying the control circuitry by avoiding continuous operation.
2Use of energy by moving object
If the regulated voltage level is kept to a minimum, then power consumption is reduced, but maintaining adequate power to all channels becomes difficult
Solution Approach 1:
The patent dynamically adjusts the regulated voltage level by keeping the DC-DC converter enabled only during time periods when the dominant LED channel requires power. During these periods, the voltage is maintained at an adequate level; during other periods, the converter is disabled, reducing power consumption. This dynamic approach ensures adequate power supply when needed while minimizing energy consumption overall.
Solution Approach 2:
The patent employs periodic action by enabling the DC-DC converter in periodic intervals corresponding to the activation of the dominant LED channel. Rather than maintaining continuous voltage regulation, the converter operates periodically only when the dominant channel is active, reducing average power consumption while ensuring adequate power is available during each active period.
3Stability of the object's composition
If the DC-DC converter operates continuously to maintain regulated voltage, then voltage stability is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic operation by enabling the DC-DC converter only during specific time periods when voltage regulation is actually needed (when the dominant LED channel is active). This dynamic approach maintains voltage stability during critical periods while avoiding continuous operation that would increase power consumption unnecessarily during periods when all channels are inactive or at minimum voltage requirements.
Data Source
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AI summary
A control circuit used to control a DC-DC converter includes a duty cycle control unit to control a duty cycle of the DC-DC converter and a hysteretic control unit to maintain a voltage at an output of the DC-DC converter within a narrow range during certain operational time periods. The hysteretic control unit may maintain the converter output voltage within the range by alternately enabling and disabling the duty cycle control unit based on feedback from the DC-DC converter output. In at least one embodiment, the control circuit is used within LED driver circuitry for driving a plurality of LED channels.