LDO Voltage Regulator Shunt Prebias for Load Transient Stability
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Solution Overview
Problem
Low dropout (LDO) voltage regulators face challenges in efficiently managing large load current transitions, leading to unwanted output voltage droop and overshoot, which requires large reservoir capacitors increasing physical size and power consumption.
Innovation Solution
Incorporating a controllable shunt device that adjusts shunt current based on control signals to prebias the output device, reducing the need for large reservoir capacitors by allowing the LDO to anticipate load current changes, thereby minimizing transient effects on the output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If large reservoir capacitors are used to manage load current transitions, then output voltage stability is improved, but physical size and power consumption increase
Solution Approach 1:
The shunt device is activated in advance of load current transitions to pre-adjust the output voltage. By detecting anticipated load changes (such as during wake-up or mode transitions), the shunt device modifies the output voltage proactively, preventing voltage droop or overshoot before they occur, thereby eliminating the need for large reservoir capacitors
Solution Approach 2:
The shunt device applies counter-action to prevent unwanted voltage transitions. By activating the shunt device before load current changes occur, it creates an opposing effect that cancels out the anticipated voltage droop or overshoot, maintaining output voltage stability without requiring large capacitive storage
2Stability of the object's composition
If large reservoir capacitors are used to manage load current transitions, then output voltage stability is improved, but power consumption increases
Solution Approach 1:
The shunt device performs preliminary voltage adjustment before load transitions occur, eliminating the need for continuous high-power operation of large reservoir capacitors. This on-demand approach reduces average power consumption while maintaining voltage stability during critical transitions
Solution Approach 2:
The shunt device automatically activates and deactivates based on detected load conditions, managing voltage stability without requiring external control circuitry or continuous power supply to large capacitors, thereby reducing overall system power consumption
3Weight of stationary object
If controllable shunt device is used to prebias output device, then need for large reservoir capacitors is reduced, but device complexity increases
Solution Approach 1:
The shunt device serves multiple functions: it prebiases the output device, manages load current transitions, and replaces the function of large reservoir capacitors. This multi-functionality justifies the added complexity by eliminating separate capacitive components and simplifying the overall power management architecture
Solution Approach 2:
The shunt device combines voltage regulation and transient management functions into a single component, merging what would traditionally require separate reservoir capacitors and regulation circuitry. This integration reduces component count and physical size despite the increased functional complexity of the shunt device itself
Data Source
AI summary
The present disclosure relates to voltage regulator circuitry. The voltage regulator circuitry comprises an output device configured to provide a regulated output voltage and a controllable shunt device configured to provide a current path from the output device for a shunt current. The shunt current is variable according to a control signal supplied to the controllable shunt device.