Switched Capacitor Buck Regulator with Phase Interleaving
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Solution Overview
Problem
Modern microprocessors with multiple cores require separate voltage regulators for each core to support dynamic voltage and frequency scaling, but existing voltage regulators face challenges such as charge sharing losses and inefficiency when deviating from target operation points, and integration of high-efficiency regulators on chip is difficult due to large magnetic components.
Innovation Solution
A voltage regulator device using a switched capacitor circuit that periodically switches between multiple voltage levels, combined with a low pass filter and phase interleaving techniques, to reduce inductor and capacitor sizes while maintaining high efficiency, allowing for step-up, step-down, and step-up/down conversions, and incorporating a controller for optimal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional buck converters are used to achieve high efficiency voltage regulation, then voltage conversion efficiency is improved, but inductor size increases making on-chip integration difficult
Solution Approach 1:
The patent segments the voltage conversion function into multiple switched capacitor circuits operating in parallel with different conversion ratios. Instead of using a single large inductor for continuous voltage conversion, the system divides the conversion task across multiple discrete capacitor-based conversion stages, each handling a portion of the total power conversion requirement.
Solution Approach 2:
The patent replaces the magnetic inductor-based voltage conversion mechanism with a capacitor-based switched capacitor system. This substitution eliminates the need for large magnetic components while achieving similar voltage conversion functionality through capacitive charge transfer and switching networks.
2Area of stationary object
If switched capacitor voltage regulators are used to reduce component size, then inductor area is reduced enabling on-chip integration, but charge sharing losses increase and efficiency degrades when deviating from target operation point
Solution Approach 1:
The patent divides the switched capacitor voltage regulation into multiple parallel conversion ratios (e.g., 1:1, 2:1, 3:1). Each ratio is optimized for specific output voltage ranges, allowing the system to operate at peak efficiency for multiple different target voltages without suffering from charge sharing losses that plague single-ratio designs.
Solution Approach 2:
The patent creates a multi-ratio switched capacitor voltage regulator that can universally provide multiple different voltage conversion ratios using the same capacitor bank and switching network. This multi-functional design allows a single circuit to replace what would traditionally require multiple separate regulators, maintaining high efficiency across different operating points.
3Area of stationary object
If multiple voltage levels are switched periodically to reduce inductor size, then inductor area is reduced, but switching losses increase
Solution Approach 1:
The patent employs periodic switching of capacitor configurations to achieve voltage conversion. By systematically cycling through different capacitor connection topologies at optimized frequencies, the system achieves continuous voltage regulation while managing switching losses through predictable, rhythmic operation patterns that allow for efficient heat dissipation and timing optimization.
Solution Approach 2:
The patent maintains continuous voltage conversion by ensuring that capacitor charging and discharging operations overlap in time. While one capacitor is charging, another is discharging to the output, eliminating idle periods and ensuring that the useful voltage conversion action continues without interruption, thereby reducing overall switching losses.
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 enables high-efficiency voltage regulation with reduced switching losses and smaller component sizes, making it suitable for on-chip integration and various electronic devices, including multi-core processors and energy harvesting systems, with improved power management and reduced area consumption.
Implementation Method 1
A voltage regulator having a switched capacitor circuit (SCC) capable of switching its output voltage periodically between two or more voltage levels
Implementation Method 2
The switched capacitor circuit is followed by a low pass filter to give a regulated output voltage
Data Source
AI summary
A voltage regulator provides a regulated output voltage [108] from an input voltage [100] using control unit [106] to control a switched capacitor circuit [102] to periodically produce different output voltage levels Vx followed by a low pass filter [104] to give a regulated output voltage. Phase interleaving is used where the phases of different voltage levels are interleaved allowing for increased effective switching frequency and reduced switching losses. By controlling the average voltage on the flying capacitors, output voltage is regulated by modulating the resistance of the switches using a duty cycle. A control unit [106] is used to determine the operation region of the voltage regulator device and configure the switched capacitor circuit in each operation region. The controller contains a state machine that determines the switches configuration in each phase of a complete switching cycle.