Multiphase Converter Voltage Loop for Phase Charge Balancing
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Solution Overview
Problem
Conventional multiphase switching converters face challenges in accurately balancing charge across phases due to limitations in current sense amplifiers, which restrict switching frequency and increase power consumption, especially at higher frequencies.
Innovation Solution
A voltage control loop is implemented to generate a feedback voltage, error voltage, and error current, which are distributed across phases to regulate the duty cycle of switching devices, enabling charge balancing with reduced complexity and lower power consumption without additional current sense amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional current sense amplifiers are used for charge balancing, then charge balance can be achieved, but switching frequency is limited and power consumption increases
Solution Approach 1:
The patent extracts the charge balancing function from the conventional current sense amplifier and implements it through a voltage control loop that operates independently of the main current sensing path. This allows charge balancing to be achieved without relying on the bandwidth-limited current sense amplifier, thereby enabling higher switching frequencies while maintaining charge balance reliability
Solution Approach 2:
The voltage control loop serves multiple functions: it performs charge balancing across phases, regulates output voltage, and operates across the full switching frequency range. By making the control loop universal, the patent eliminates the need for separate high-bandwidth current sense amplifiers dedicated solely to charge balancing, thus reducing power consumption while maintaining both charge balance and high switching frequency capability
2Reliability
If conventional current sense amplifiers are used for charge balancing, then charge balance can be achieved, but power consumption increases
Solution Approach 1:
The charge balancing function is extracted from the power-intensive current sense amplifier and implemented through a voltage control loop that operates with lower power consumption. This separation allows the main current sensing path to remain high-performance while the charge balancing function achieves adequate performance with reduced energy requirements
Solution Approach 2:
The patent employs a simpler, lower-cost voltage control loop architecture for charge balancing instead of expensive, high-power current sense amplifiers. The voltage control loop provides sufficient charge balancing performance without the high power consumption and cost associated with high-bandwidth current sensing circuits
3Productivity
If voltage control loop is used for charge balancing, then switching frequency can be increased and power consumption reduced, but additional control circuitry is required
Solution Approach 1:
The voltage control loop is designed to perform multiple functions including charge balancing, output voltage regulation, and phase current equalization. By making the control loop universal and multi-functional, the patent avoids adding dedicated separate circuits for each function, thereby minimizing the increase in overall device complexity while achieving higher switching frequencies and reduced power consumption
Data Source
AI summary
A multiphase switching converter includes: a plurality of phases, each phase including a current detection device, a set of switching devices, an output capacitor coupled to each phase of the plurality of phases, and a control circuit. The current detection device of each phase of the plurality of phases is configured to receive an error current from the control circuit and generate a corresponding signal to control a duty cycle of a set of corresponding switching devices such that each phase delivers a substantially equal quantity of charge to the corresponding output capacitor to maintain a charge balance on the corresponding output capacitor.