SIMO Regulator Switching Control for Cross-Regulation Stability
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Solution Overview
Problem
Single inductor multiple output voltage regulators face challenges in stability and cross-regulation, where variations in one output can affect other outputs due to shared inductors, leading to inefficiencies and instability.
Innovation Solution
A control circuit with output switches and a controller that manages switching periods to prioritize outputs and adjust connected time durations, using a Charge Controlled Energizing Cycle per Switching Period (CCECSP) method to reduce cross-regulation and enhance stability, allowing independent regulated voltages across multiple outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single inductor is shared among multiple outputs, then the circuit area and number of components are reduced, but cross-regulation and stability issues arise
Solution Approach 1:
The patent implements dynamic priority assignment where the controller can switch which output has priority access to the inductor based on real-time conditions. This dynamic control allows the system to adapt to varying load conditions while maintaining stability, resolving the contradiction between component reduction and reliability.
Solution Approach 2:
The control circuit continuously monitors output voltages and adjusts switching timing accordingly. This feedback mechanism ensures that even with a shared inductor, each output maintains stable voltage regulation by compensating for changes in real-time, thus maintaining reliability while using fewer components.
2Device complexity
If a single inductor is shared among multiple outputs, then the number of discrete components is reduced, but cross-regulation occurs
Solution Approach 1:
The control circuit segments the inductor's usage by assigning different priority levels to different outputs at different times. By dividing the inductor access into prioritized time slots based on output needs, the system reduces cross-regulation effects while maintaining the benefit of using a single inductor component.
Solution Approach 2:
The controller dynamically changes switching parameters such as connected time duration and switching timing based on which output currently has priority. This parameter adjustment allows the system to minimize cross-regulation by optimizing inductor usage patterns for different output conditions.
3Productivity
If outputs are connected to the inductor simultaneously, then all outputs can be regulated, but instability and incorrect control of switching instances occur
Solution Approach 1:
The controller implements periodic switching with defined phases where different outputs are connected to the inductor in sequence rather than simultaneously. This periodic action with structured timing ensures stable switching control while still providing regulation capability to all outputs over time.
Solution Approach 2:
The system dynamically adjusts which outputs are connected to the inductor based on current conditions and priority assignments. This dynamic control prevents simultaneous connection conflicts while ensuring all outputs receive regulation attention, maintaining both productivity and switching stability.
Data Source
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AI summary
Disclosed are control circuits for a SIMO voltage regulator, and associated voltage regulators. The control circuit comprises output switches for selective connection of each output to a first inductor terminal; and a controller. In an embodiment, the controller such that each output is periodically connected to the first inductor terminal for a respective connected time duration which are each dependent on at least one historical voltage value sampled in an earlier switching period on at least one of the outputs. In another embodiment, the output for which at least a first portion of its corresponding connected time duration is first calculated is periodically switched. In yet another embodiment, it is determined whether the SIMO is in a locked condition; whether the locked condition is valid; and if invalid, a respective alternative voltage regulator is used to supply one or more of the outputs.