Linear Regulator Ballast Devices for Sleep Transition Voltage Stability
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Solution Overview
Problem
On-chip linear dropout regulators (LDOs) introduce undesirable voltage transients during power mode transitions, causing downstream circuitry to receive voltages below brownout levels, leading to unwanted behavior such as spontaneous resetting.
Innovation Solution
A linear voltage regulator with multiple ballast devices controlled by successively delayed ballast control signals to manage capacitance additions during power mode transitions, preventing output voltage swings below brownout levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If on-chip LDOs use transistors and small capacitors instead of large inductive and capacitive components, then parts count and chip I/O are reduced, but voltage transients and ripples are introduced at the output
Solution Approach 1:
The patent divides the single ballast device into multiple segmented ballast devices (first ballast device, second ballast device, etc.) that are activated sequentially. Each ballast device provides a portion of the total ballast effect, and by activating them in sequence with different delays, the system achieves smoother transient response while maintaining the compact on-chip structure with small capacitors.
Solution Approach 2:
The patent applies preliminary action by activating ballast devices in advance before the main load transitions. The first ballast device is activated with a first delay, and subsequent ballast devices are activated with progressively longer delays, preparing the output capacitance in advance to counteract the upcoming transient effects when the load changes state.
2Stability of the object's composition
If multiple ballast devices are activated simultaneously to counteract voltage transients, then voltage stability is improved, but the complexity of control signals increases
Solution Approach 1:
The control approach segments the simultaneous activation into sequential activation with different delays. Instead of activating all ballast devices at once or using complex simultaneous control logic, each ballast device is controlled by a separate delayed version of the sleep signal, simplifying the control architecture while maintaining voltage stability.
Solution Approach 2:
The patent introduces delay elements as intermediary components between the sleep signal and each ballast device control input. These delay elements act as mediators that automatically create the required time sequencing without complex control logic, transforming a potentially complex simultaneous control problem into a series of simple delayed activations.
3Reliability
If ballast devices are activated with different delays during sleep transitions, then voltage dips below brownout levels are prevented, but the device complexity increases
Solution Approach 1:
The patent applies periodic action through the use of systematically spaced delay intervals. The first ballast device is activated with a first delay, the second ballast device with a second delay greater than the first, and so on. This periodic, progressively delayed activation pattern creates a controlled ramp-up of ballast effect that reliably prevents brownout while maintaining a simple, predictable control structure.
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 stabilizes output voltage during power mode transitions, preventing voltage dips below brownout levels and ensuring reliable operation of downstream circuitry.
Implementation Method 1
activating a first additional ballast device of the linear voltage regulator to add first additional capacitance to a load corresponding to the power mode
Data Source
AI summary
An electronic system having a linear voltage regulator and method of operating the linear voltage regulator. A linear voltage regulator of an electronic system has at least three ballast devices. The method of operating includes producing a voltage at an output terminal that is electrically coupled to a node of a first one of the three or more ballast devices; receiving a power mode indication; activating a first additional ballast device of the linear voltage regulator to add first additional capacitance to a load corresponding to the power mode; generating one or more successively delayed ballast control signals based at least in part on the power mode indication; and activating, using the successively delayed ballast control signals, second additional ballast devices of the linear voltage regulator to add second capacitances to the load of the linear voltage regulator.