Adaptive On-Time Switched-Mode Power Supply Ripple Control
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Solution Overview
Problem
Conventional switching regulator DC-DC converters with adaptive on-time function in ripple control methods require an additional terminal for output voltage monitoring, increasing costs and limiting the number of external terminals, which can prevent the mounting of the adaptive on-time function due to terminal limitations.
Innovation Solution
A switched-mode power supply with a control circuit on a semiconductor chip that includes a simulated voltage generation circuit to smooth the voltage at the node connecting the drive switching element and inductor, generating a simulated voltage corresponding to the output voltage, and a timer that measures time based on input and simulated voltages to control the pulse width of the drive pulse, maintaining a constant switching cycle without the need for an additional terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an adaptive on-time function is implemented in a ripple control method DC-DC converter, then the load response speed is improved, but the number of external terminals increases leading to cost increase
Solution Approach 1:
The patent introduces an intermediary circuit that generates a simulated voltage corresponding to the output voltage. This simulated voltage serves as a mediator that allows the adaptive on-time function to operate without direct access to the actual output voltage terminal, thereby maintaining high load response speed while avoiding the need for additional external terminals.
Solution Approach 2:
The patent creates a copy of the output voltage signal in the form of a simulated voltage generated by the voltage generation circuit. This copied signal enables the timer to function with adaptive on-time control without requiring a direct connection to the output voltage terminal, thus resolving the terminal limitation while preserving the adaptive control capability.
2Stability of the object's composition
If an adaptive on-time function is implemented in a ripple control method DC-DC converter, then the switching frequency stability is improved, but the number of external terminals increases limiting IC mounting
Solution Approach 1:
The voltage generation circuit acts as an intermediary that provides the timer with a simulated voltage representation of the output voltage. This intermediary mechanism enables the timer to adjust the on-time period based on input voltage and simulated voltage variations, maintaining switching frequency stability without requiring additional external terminals that would limit IC mounting.
Solution Approach 2:
The patent generates a copied version of the output voltage signal through the voltage generation circuit. This copied simulated voltage allows the adaptive on-time function to maintain switching frequency stability by compensating for voltage variations without requiring direct access to the output terminal, thus enabling IC implementation with limited external terminals.
3Speed
If an adaptive on-time function is implemented in a ripple control method DC-DC converter, then the load response speed is improved, but the manufacturing cost increases
Solution Approach 1:
The voltage generation circuit serves as a cost-effective intermediary that enables adaptive on-time control without requiring additional external terminals. By generating a simulated voltage internally, the system achieves high load response speed while avoiding the cost increase associated with additional terminals and their associated PCB routing and assembly complexities.
Solution Approach 2:
The patent creates an internal copy of the output voltage signal through the voltage generation circuit, eliminating the need for additional external terminals. This copying approach reduces manufacturing costs by simplifying the terminal structure while maintaining the high load response speed capability through adaptive on-time control.
Data Source
AI summary
A ripple-control switched-mode power supply includes a control circuit to switch on/off a drive switching element. The control circuit includes a simulated voltage generation circuit that smoothes a voltage at a node connecting the drive switching element and an inductor and that generates a simulated voltage corresponding to an output voltage; a timer that measures a time corresponding to an input voltage and the simulated voltage; a voltage comparison circuit that compares a feedback voltage and a predetermined voltage; and a control pulse generation circuit that generates a control pulse having a pulse width corresponding to the time based on outputs from the timer and the voltage comparison circuit. The control circuit varies the pulse width of the control pulse in accordance with a variation in the input voltage to maintain a constant switching cycle.