Power Source Control Device Multi-Channel PWM Phase Shifting
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Solution Overview
Problem
Conventional power source control devices require multiple timer ports for PWM control of lighting loads, leading to high costs and increased inrush current and noise due to coincident phases, and struggle with immediate lighting control due to synchronization issues between microcomputers and PWM periods.
Innovation Solution
A power source control device that performs multi-channel PWM control without using a timer port by generating operation data sets for each predetermined period within the PWM period, allowing each power source unit to be controlled independently, thereby shifting phases and reducing noise, and enabling immediate lighting control through updated operation data output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple timer ports are used for PWM control of multiple lighting loads, then each load can be controlled independently with phase shifting capability, but the device cost increases and the system complexity increases
Solution Approach 1:
The single timer port is made universal by generating multiple PWM signals through software processing. The control device uses one timer port to generate a base PWM signal, then processes this signal through AND operations with phase shift data to create multiple phase-shifted PWM signals for different lighting loads, eliminating the need for multiple timer ports while maintaining independent control capability.
Solution Approach 2:
Phase shift data serves as an intermediary element between the single timer port and multiple lighting loads. The phase shift data stores timing information that mediates the conversion of a single PWM signal into multiple phase-shifted signals, enabling independent control without additional hardware timer ports.
2Device complexity
If a single PWM period timer is used for all power source units, then the device complexity is reduced, but the phases of lighting loads coincide causing increased inrush current and noise
Solution Approach 1:
Phase shift data is prepared in advance to assign different timing characteristics to each power source unit. By pre-configuring the phase shift data with different ordinal numbers for each unit, the system ensures that power source units operate at different phases within the PWM period, preventing simultaneous ON operations and reducing inrush current and noise before they occur.
Solution Approach 2:
The system changes the timing parameter (phase) of each power source unit by utilizing different cycles of the predetermined period within the PWM period. This parameter variation ensures that even with a single timer port, each power source unit operates at a different phase, preventing coincident phases and their associated harmful effects.
3Object-generated harmful factors
If phase shifting is implemented to reduce inrush current and noise, then harmful factors are reduced, but additional circuits are required for synchronization between microcomputer and PWM period timer
Solution Approach 1:
The microcomputer itself generates and manages the phase shift data without requiring external synchronization circuits. The system uses self-service by having the microcomputer's CPU generate PWM signals through software processing using the phase shift data, eliminating the need for additional hardware synchronization circuits while maintaining phase shifting capability.
Solution Approach 2:
The patent replaces the mechanical/hardware synchronization circuit with a software-based solution. Instead of using physical circuits to synchronize the microcomputer with the PWM period timer, the system uses software processing to generate PWM signals that inherently incorporate phase shifting information, substituting electronic hardware with software logic.
4Illumination intensity
If timer ports are used for PWM control, then brightness maintaining control is achieved, but the cost of the microcomputer increases
Solution Approach 1:
Instead of using multiple physical timer ports, the system creates virtual copies of timer functionality through software. The single timer port's PWM signal is copied and processed multiple times with different phase shift data, creating multiple virtual PWM channels that provide brightness control for multiple lighting loads without requiring a expensive multi-timer microcomputer.
Data Source
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AI summary
Provided is a power source control device that realizes multi-channel PWM control without using a timer port, and a power source control method for the same. A power source control device performs PWM control on a plurality of power source units that repeat an ON operation and an OFF operation in cycles having a predetermined PWM period. The power source control device includes: a generation unit configured to generate operation data for the entire PWM period, the operation data determining whether to cause the individual power source units to perform the ON operation or the OFF operation in cycles having a predetermined period that is shorter than the PWM period; and an output unit configured to output operation data generated by the generation unit to the plurality of power source units in cycles of the predetermined period.