Flying Capacitor Power Converter Extended Voltage Ratio
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Solution Overview
Problem
Conventional buck converters are limited by significant conduction losses and electromagnetic interferences, and multi-phase buck converters with extended duty cycle can only operate with a maximum output-to-input voltage conversion ratio of ¼, which is not sufficient to maintain desired output voltage when the input voltage drops due to battery depletion.
Innovation Solution
A power converter design that includes a network of switches and flying capacitors, with a driver controlling the switches to operate in specific sequences of states, allowing the converter to achieve an extended output-to-input voltage conversion ratio greater than ¼, enabling efficient operation as both a step-down and step-up converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multi-phase buck converters with extended duty cycle are used, then conduction losses and electromagnetic noise are reduced, but the output-to-input voltage conversion ratio is limited to maximum 1/4
Solution Approach 1:
The converter is divided into multiple phases with separate inductors and flying capacitors, where each phase operates independently but cooperatively. This segmentation allows the converter to achieve extended voltage conversion ratios while maintaining the low conduction losses and electromagnetic noise characteristics of multi-phase topologies.
Solution Approach 2:
The invention introduces flying capacitors that operate in a different voltage dimension, enabling voltage multiplication beyond the traditional duty cycle limits. By utilizing the voltage across flying capacitors in addition to the input voltage, the converter achieves output-to-input ratios greater than 1/4 while maintaining multi-phase benefits.
2Object-affected harmful factors
If multi-phase buck converters with extended duty cycle are used, then electromagnetic noise is reduced, but the output-to-input voltage conversion ratio is limited to maximum 1/4
Solution Approach 1:
The converter is divided into multiple phases with separate inductors and flying capacitors, where each phase operates independently but cooperatively. This segmentation allows the converter to achieve extended voltage conversion ratios while maintaining the low conduction losses and electromagnetic noise characteristics of multi-phase topologies.
Solution Approach 2:
The invention introduces flying capacitors that operate in a different voltage dimension, enabling voltage multiplication beyond the traditional duty cycle limits. By utilizing the voltage across flying capacitors in addition to the input voltage, the converter achieves output-to-input ratios greater than 1/4 while maintaining multi-phase benefits.
3Reliability
If the maximum duty cycle is reduced to enable regulation, then output voltage regulation capability is improved, but the maximum output voltage decreases to VIN/6
Solution Approach 1:
The converter incorporates feedback control that monitors the output voltage and adjusts the duty cycle of each phase accordingly. The flying capacitor voltages are regulated through feedback control, enabling precise output voltage regulation while maintaining the ability to achieve higher output voltages through the extended topology.
Solution Approach 2:
The invention introduces flying capacitors that operate in a different voltage dimension, enabling voltage multiplication beyond the traditional duty cycle limits. By utilizing the voltage across flying capacitors in addition to the input voltage, the converter achieves output-to-input ratios greater than 1/4 while maintaining multi-phase benefits.
4Device complexity
If conventional buck converters are used, then circuit simplicity is maintained, but conduction losses are significant
Solution Approach 1:
The converter is divided into multiple phases with separate inductors and flying capacitors, where each phase operates independently but cooperatively. This segmentation allows the converter to achieve extended voltage conversion ratios while maintaining the low conduction losses and electromagnetic noise characteristics of multi-phase topologies.
Solution Approach 2:
The invention merges the benefits of multi-phase topologies with extended voltage conversion capability by combining multiple inductors, flying capacitors, and switches in a coordinated manner. This merging achieves low conduction losses through current sharing while enabling voltage ratios beyond conventional limits.
Data Source
AI summary
A power converter includes two flying capacitors coupled to a network of switches, two inductors and a driver. The network of switches has a first switch to couple the first flying capacitor to a first port, a first ground switch to couple the first flying capacitor to ground, a second switch to couple the second flying capacitor to the first port, a second ground switch to couple the second flying capacitor to ground. The driver drives the network of switches with a sequence of states comprising a first state. In the first state the first port is coupled to a second port via a first path and a second path. The first path includes the first switch, the first flying capacitor and the first inductor. The second path includes the second switch, the second flying capacitor and the second inductor; the ground port is decoupled from the second port.