PMOS Power Switch for Combined DC-DC and Linear Regulation
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Solution Overview
Problem
Integrated circuit devices face inefficiencies and high silicon real estate costs due to the need for both DC-DC converters and linear regulators to achieve optimal voltage regulation across a wide supply voltage range, as existing solutions either require large silicon areas or compromise on efficiency by using one or the other based on voltage levels.
Innovation Solution
A voltage regulator that utilizes a common PMOS power transistor for both DC-DC and linear regulation modes, switching between modes based on measured supply voltage to optimize efficiency, sharing a common voltage reference and operational amplifier, and employing signal switches to select between DC-DC and linear regulation configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If both DC-DC converter and linear regulator are integrated into a single circuit device, then optimal efficiency across wide supply voltage range is achieved, but silicon real estate area and manufacturing cost increase
Solution Approach 1:
The patent merges the DC-DC converter and linear regulator into a single integrated circuit device, allowing both voltage regulation modes to coexist on the same silicon die. The power pass transistor is shared between both regulators, and the control circuits are integrated to manage switching between modes based on supply voltage conditions, achieving optimal efficiency across wide voltage ranges while controlling area usage.
Solution Approach 2:
The power pass transistor is designed to serve dual functions as both the DC-DC converter power switch and the linear regulator pass transistor. The control circuitry is configured to universally manage both regulation modes, selecting the appropriate mode based on supply voltage levels, thereby maximizing the utility of each component and reducing overall area requirements.
2Reliability
If DC-DC converter and linear regulator are kept separate and independent, then each regulator can be optimized for its specific function, but silicon real estate area increases due to duplicate power circuits
Solution Approach 1:
The patent combines the power circuits of the DC-DC converter and linear regulator into a shared configuration. The power pass transistor is commonly used by both regulators, and the inductor and capacitor networks are integrated to serve both functions. This merging eliminates duplicate power components while maintaining the independent optimization capabilities of each regulation mode through shared control logic.
3Area of stationary object
If only one regulator type is used based on supply voltage level, then silicon area is reduced, but efficiency is compromised across the entire voltage range
Solution Approach 1:
The patent implements dynamic switching between DC-DC converter and linear regulator modes based on the supply voltage level. The control circuit continuously monitors the supply voltage and automatically selects the optimal regulation mode: DC-DC converter mode for higher supply voltages where switching efficiency is superior, and linear regulator mode for lower supply voltages where linear regulation is more efficient. This dynamic adaptation maintains optimal efficiency across the entire voltage range while using a single integrated circuit.
Solution Approach 2:
The patent changes the operating parameter (regulation mode) based on the supply voltage parameter. When supply voltage exceeds a threshold, the system switches to DC-DC converter mode; when supply voltage is below the threshold, it operates in linear regulator mode. This parameter-based mode selection ensures optimal efficiency at all operating conditions while avoiding the need for separate dedicated circuits for each mode.
Data Source
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AI summary
A P-MOS transistor may be used as either a switch in a DC-DC converter or as a pass transistor of a linear regulator. When a supply voltage is above a certain voltage, the P-MOS transistor will be used in the DC-DC converter and when below the certain voltage the P-MOS transistor will be used in the linear regulator. The supply voltage may be monitored with a voltage comparator that compares the supply voltage to the certain voltage. Above the certain voltage the DC-DC converter is more efficient than the linear regulator and below the certain voltage the linear voltage regulator is more efficient than the DC -DC converter. Alternatively, selecting either the DC-DC converter or linear regulator may be done by using bonding, a jumper, a fuse link or programming a bit for different product applications during integrated circuit package fabrication or end product manufacturing.