Current Source Circuit Duty Cycle Control
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Solution Overview
Problem
Existing power supply circuits require complex and costly designs with amplitude modulation and low pass filters to correlate output voltage with duty cycle information, leading to accuracy loss and increased complexity.
Innovation Solution
A current source circuit that directly controls output current with duty cycle information using an operational transconductance amplifier and shunt circuit, eliminating the need for amplitude modulation and low pass filters, thereby simplifying the design and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If amplitude modulation circuit and low pass filter are introduced to correlate output voltage with duty cycle information, then the power supply can meet load requirements, but circuit complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the unnecessary amplitude modulation circuit and low pass filter from the conventional power supply design. By directly using the duty cycle information to control the switching elements, the patent achieves the same load adaptation function without these additional components, thereby reducing circuit complexity while maintaining versatility.
Solution Approach 2:
The patent makes the switching elements perform multiple functions: they both switch the power flow and directly encode the duty cycle information in their control signals. This multi-functionality eliminates the need for separate amplitude modulation circuits, as the switching control itself carries the modulation information needed to meet various load requirements.
2Adaptability or versatility
If amplitude modulation circuit and low pass filter are introduced to correlate output voltage with duty cycle information, then the power supply can meet load requirements, but conversion accuracy is lost
Solution Approach 1:
The patent removes the amplitude modulation circuit and low pass filter that cause accuracy loss during conversion. By directly controlling the switching elements with duty cycle information, the patent preserves the original signal accuracy without the degradation introduced by analog modulation and filtering processes.
Solution Approach 2:
The patent replaces the analog amplitude modulation mechanism with a direct digital control approach. Instead of using continuous analog signals that require modulation and filtering, the patent uses discrete switching control signals that directly embody the duty cycle information, eliminating conversion accuracy loss.
3Adaptability or versatility
If additional amplitude modulation circuit and low pass filter are introduced, then the output signal can be correlated with duty cycle information, but chip area and cost increase
Solution Approach 1:
The patent extracts and removes the additional amplitude modulation circuit and low pass filter from the design. By implementing direct duty cycle control through switching elements, the patent achieves output correlation with duty cycle information without requiring these space-consuming analog processing circuits, thereby reducing chip area.
Solution Approach 2:
The patent merges the duty cycle control function directly into the switching element control. Instead of having separate amplitude modulation and filtering stages, the control signal for the switching elements directly contains the duty cycle information, combining multiple functions into a single integrated control mechanism that reduces chip area.
Data Source
AI summary
A current source circuit and an LED driving circuit applying the same. A current at an output terminal of an operational transconductance amplifier is shunted based on a first control signal that includes duty cycle information, or an input signal at at least one input terminal of the operational transconductance amplifier is controlled to be switched between different voltage signals based on the first control signal, so as to adjust an output current of a current adjustment circuit. A driving voltage for driving a current generation circuit is adjusted based on the output current. Thereby, a driving current generated by the current source circuit is correlated with the duty cycle information. An amplitude modulation circuit used, a low-pass filter and the like for processing the first control signal are not used, effectively simplifying circuit design and improving system efficiency.