DC-DC Converter with Auxiliary Current Paths for Fast Settling
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Solution Overview
Problem
Conventional DC-DC converters face a tradeoff between settling time and output voltage ripple, with smaller inductance reducing settling time but increasing ripple, and additional charging paths are difficult to control effectively.
Innovation Solution
A DC-DC converter design incorporating a switch module, pull-up circuit, and pull-down circuit, where the currents provided by these circuits are determined based on the inductor current, allowing for controlled alternation between charging and discharging to optimize settling time without reducing inductance, thereby minimizing ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the inductance of the inductor is reduced to shorten the settling time, then the settling time is improved, but the output voltage ripple increases
Solution Approach 1:
The patent segments the current path by introducing a separate auxiliary inductor (second inductor) parallel to the main inductor (first inductor). This segmentation allows the auxiliary inductor to specifically handle the ripple current component while the main inductor maintains the primary energy storage function, thereby reducing output voltage ripple without compromising settling time performance
Solution Approach 2:
The auxiliary inductor serves multiple functions: it provides an additional current path during switching transitions, suppresses output voltage ripple, and assists in rapid settling. By making this component multi-functional, the patent achieves ripple reduction and fast settling time simultaneously without requiring the main inductor to be downsized
2Loss of time
If an additional charging path is added to shorten the settling time, then the settling time is improved, but the circuit control complexity increases due to inappropriate current setting
Solution Approach 1:
The control circuit monitors the output voltage and dynamically adjusts the duty cycle of the auxiliary inductor's charging path based on the actual voltage level. This feedback mechanism ensures that the additional charging current is appropriately controlled, preventing overshoot and oscillation while achieving fast settling, thereby avoiding the control complexity issue
Solution Approach 2:
The patent implements dynamic control where the auxiliary inductor is selectively enabled or disabled based on the converter's operating state. During transient conditions, the auxiliary path is activated to provide rapid charging; during steady-state, it is deactivated. This dynamic operation simplifies control compared to continuously managing multiple current paths
Data Source
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AI summary
A DC-DC converter (100) includes an inductor (110), a switch module (MP, MN), a pull-up circuit (1 20) and a pull-down circuit (1 30). The inductor (1 10) has a first node and a second node, and the second node is coupled to an output node (Nout) of the DC-DC converter (1 00). The switch module (MP, MN) is arranged for selectively connecting an input voltage or a ground voltage to the first node of the inductor (110) according to a driving signal. The pull-up circuit (120) is arranged for selectively providing a first current to the output node (Nout) of the DC-DC converter (100). The pull-down circuit (130) is arranged for selectively sinking a second current from the output node (Nout) of the DC-DC converter (100). In addition, at least one of the first current provided by the pull-up circuit (120) and the second current sunk by the pull-down circuit (130) is determined based on an inductor current flowing through the inductor (110).