SIMO DC-DC Converter Control for Cross-Regulation Stability
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Solution Overview
Problem
Conventional single-inductor multiple-output (SIMO) DC-DC converters face challenges in managing load variations across multiple outputs, leading to cross-regulation issues, which often require complex solutions that increase size and reduce efficiency, making them unsuitable for mass-market applications.
Innovation Solution
A SIMO DC-DC converter design that uses an inductor to buffer energy and a control structure to generate control signals, allowing the inductor to be energized and de-energized in cycles based on the total current demand of the loads, thereby reducing cross-regulation issues without compromising efficiency or increasing size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solutions are used to prevent or reduce the impact of load variations, then cross-regulation issues are reduced, but energy efficiency decreases and space requirements increase
Solution Approach 1:
The control structure determines the duration of the first time segment (energizing phase) based on the sum of currents required by all loads before the conversion cycle begins. This preliminary determination allows the system to pre-calculate the energy storage requirements, ensuring that the inductor is properly charged to supply all outputs without cross-regulation issues, while avoiding unnecessary energy losses from continuous monitoring and adjustment during operation.
2Reliability
If conventional solutions are used to prevent or reduce the impact of load variations, then cross-regulation issues are reduced, but device size increases
Solution Approach 1:
The single inductor serves multiple functions: it stores energy for all output loads simultaneously, and its charging duration is determined based on the aggregate current requirements of all loads. This multi-functional approach eliminates the need for separate inductors or complex control circuits for each output, thereby maintaining cross-regulation stability while keeping the device compact and suitable for mass production.
3Measurement precision
If precise control of every output voltage is implemented, then output voltage precision is improved, but device complexity increases
Solution Approach 1:
The control structure determines the duration of the energizing time segment based on the sum of currents required by all loads before the conversion cycle begins. This preliminary determination simplifies the control approach by using a single calculated parameter rather than complex real-time feedback for each output, thereby maintaining output voltage precision while reducing overall device complexity.
4Device complexity
If the inductor is energized for a fixed duration, then control simplicity is improved, but adaptability to load variations decreases
Solution Approach 1:
The control structure determines the duration of the energizing time segment based on the sum of currents required by all loads before the conversion cycle begins. This preliminary determination allows the system to adapt to different load conditions by calculating the appropriate charging duration in advance, ensuring that the inductor stores sufficient energy for all outputs without requiring complex real-time adjustments during operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively manages load variations across multiple outputs, reducing cross-regulation issues while maintaining high efficiency and compact size, making it suitable for high-volume production and low-power applications.
Implementation Method 1
an inductor connected to the input node and the output node and being configured to buffer energy; wherein in one time segment the inductor being energized, wherein the duration of the one time segment being determined by the control structure prior to a start of the cycle of operation, based on a sum of the set of currents suppliable to the plurality of loads
Data Source
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AI summary
The invention relates to a single-inductor multiple-output (SIMO) DC-DC converter (1), comprising: - an electrical DC voltage source (Vs) switchable connected to an input node (ni) through an input switch (S1, S2); - a plurality of loads (Ro1, Ro2, RoN) each being switchable connected to an output node (no) through one output switch (So1, So2, SoN) of a plurality of output switches (So1, So2, SoN), wherein the electrical DC voltage source (Vs) and the loads (Ro1, Ro2, RoN) are external to the SIMO DC-DC converter (1); - an inductor (L) connected to the input node (ni) and the output node (no) and being configured to buffer energy; - a control structure arranged to operate in consecutive cycles and being configured to generate control signals for the input switch (S1, S2) and the output switches (So1, So2, SoN), wherein the inductor (L) being energized and de-energized in one cycle of operation (Tcycle) for supplying the plurality of loads (Ro1, Ro2, RoN) with a set of currents (lact) within the said cycle of operation (Tcycle), wherein the control structure being configured to section the cycle of operation (Tcyc/e) into a plurality of consecutive time segments (tup, tdown) with a duration, wherein in one time segment (tup) the inductor (L) being energized, wherein the duration of the one time segment (tup) being determined by the control structure prior to a start of the cycle of operation (Tcycle), based on a sum of the set of currents (lact) suppliable to the plurality of loads (Ro1, Ro2, RoN). The invention also relates to a method for operating a SIMO DC-DC converter (1).