DC-DC Converter Fixed On-Time Control Eliminates Ripple Generator
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Solution Overview
Problem
Conventional DC-DC converters require complex circuit structures and high current consumption due to the need for a ripple generator, and are vulnerable to noise, necessitating a simpler and more noise-resistant solution.
Innovation Solution
A DC-DC converter design that eliminates the ripple generator by using a power switch with a fixed on-time power driving signal, a voltage-controlled oscillating block, and a target tracking block with PID control to stabilize the output voltage, reducing circuit complexity and current consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ripple generator is used to generate the ramp signal, then the output voltage can be restored to target level, but the circuit structure becomes complicated and current consumption increases
Solution Approach 1:
The patent extracts and removes the ripple generator from the DC-DC converter circuit, replacing it with a fixed on-time control mechanism. The ramp signal generation function is eliminated by using a power driving signal with predetermined fixed on-time, thereby simplifying the circuit structure while maintaining output voltage restoration capability through the target tracking block and feedback mechanism
Solution Approach 2:
The patent implements self-service by using the output voltage feedback itself to generate the control signal for the power switch. The target tracking block compares the feedback voltage with a target reference voltage and automatically adjusts the power driving signal duty cycle, eliminating the need for external ripple generation components and achieving automatic output voltage regulation
2Reliability
If a ripple generator is used to generate the ramp signal, then the output voltage can be restored to target level, but current consumption increases
Solution Approach 1:
The patent extracts and removes the ripple generator from the DC-DC converter circuit, replacing it with a fixed on-time control mechanism. The ramp signal generation function is eliminated by using a power driving signal with predetermined fixed on-time, thereby simplifying the circuit structure while maintaining output voltage restoration capability through the target tracking block and feedback mechanism
Solution Approach 2:
The patent implements self-service by using the output voltage feedback itself to generate the control signal for the power switch. The target tracking block compares the feedback voltage with a target reference voltage and automatically adjusts the power driving signal duty cycle, eliminating the need for external ripple generation components and achieving automatic output voltage regulation
3Reliability
If a conventional ramp signal is used, then the output voltage can be controlled, but the system becomes vulnerable to noise
Solution Approach 1:
The patent replaces the conventional ramp signal with a fixed on-time power driving signal that has inherent noise immunity. By using a predetermined fixed on-time control mechanism rather than a continuously varying ramp signal, the system becomes less susceptible to noise interference while maintaining effective output voltage control through the feedback-based target tracking mechanism
Solution Approach 2:
The patent implements self-service by using the output voltage feedback itself to generate the control signal for the power switch. The target tracking block compares the feedback voltage with a target reference voltage and automatically adjusts the power driving signal duty cycle, eliminating the need for external ripple generation components and achieving automatic output voltage regulation
4Adaptability or versatility
If the cycle of the power driving signal varies, then the output voltage can be adjusted, but the on-time becomes unstable
Solution Approach 1:
The patent applies dynamics by making the duty cycle of the power driving signal adjustable through the target tracking block while keeping the on-time fixed. The system dynamically adapts to different output voltage requirements by varying the duty cycle (ratio of on-time to period) rather than changing the on-time itself, thereby maintaining on-time stability while achieving output voltage adaptability
Solution Approach 2:
The patent changes the parameter being controlled from on-time to duty cycle. By keeping the on-time fixed and adjusting the duty cycle through variations in the power driving signal period, the system achieves output voltage adjustment capability while maintaining on-time stability, effectively decoupling these two parameters
Data Source
AI summary
A DC-DC converter includes a voltage converting block that converts an input supply voltage to an output voltage and includes a power switch turning on at on-time of a power driving signal, a power driving block that generates the power driving signal using an oscillation output signal, wherein a cycle of the power driving signal varies according to a cycle of the oscillation output signal and a length of the on-time of the power driving signal is fixed to a power time regardless of variation of the cycle of the oscillation output signal, a voltage-controlled oscillating block that generates the oscillation output signal, the cycle of which is controlled according to a level of an oscillation control signal, and a target tracking block that generates a feedback voltage and controls the level of the oscillation control signal such that a feedback voltage follows a target reference voltage.