Multi-Stage LDO Regulator for Low Quiescent Current Switching
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Solution Overview
Problem
Conventional low dropout (LDO) voltage regulators for battery-operated devices face challenges in maintaining high performance in active modes while consuming low current in low power modes, and they often experience voltage drops during mode transitions, requiring more silicon area and introducing ripple in low power modes.
Innovation Solution
A novel LDO voltage regulator design utilizing a single input stage and multiple output stages within an error amplifying module, where the first output stage is activated during high performance mode and the second output stage is active in both high performance and low power modes, allowing for smooth transitions and reduced quiescent current consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional LDO voltage regulator uses a single pass transistor design, then the circuit complexity is low, but it cannot simultaneously achieve low quiescent current in low power mode and high performance in active mode
Solution Approach 1:
The error amplifying module is segmented into multiple output stages (first output stage and second output stage), each optimized for different power modes. The first output stage drives the first pass transistor during high performance mode, while the second output stage drives the second pass transistor during low power mode, enabling mode-specific optimization without requiring a completely separate LDO for each mode.
Solution Approach 2:
The error amplifying module is designed with multi-functionality to serve both high performance and low power modes through its multiple output stages. A single error amplifying module with multiple output stages can adapt to different operating conditions, eliminating the need for separate dedicated LDO circuits for each power mode while maintaining optimal performance in both scenarios.
2Adaptability or versatility
If separate LDOs are used for high performance mode and low power mode, then performance in both modes is optimized, but the silicon area increases
Solution Approach 1:
Multiple LDO functions are merged into a single integrated circuit. The error amplifying module combines multiple output stages that can drive different pass transistors depending on the power mode, effectively consolidating what would traditionally require separate LDO circuits into one unified structure, thereby reducing silicon area while maintaining mode-specific optimization.
Solution Approach 2:
The error amplifying module is designed as a universal component that can adapt to different power modes through its multiple output stages. This multi-functional design allows a single component to replace multiple dedicated components, achieving both high performance mode and low power mode optimization without the area overhead of separate LDO circuits.
3Loss of energy
If mode transitions are implemented in conventional LDOs, then power saving is achieved, but voltage drops (undershoot/overshoot) occur during transitions
Solution Approach 1:
The error amplifying module with multiple output stages is prepared in advance to handle mode transitions smoothly. By having multiple output stages ready and configured, the system can switch between high performance mode and low power mode without abrupt changes, as the transition path is pre-established through the modular architecture of the error amplifying module.
Solution Approach 2:
The LDO voltage regulator employs dynamic switching between different output stages based on the power mode requirements. The error amplifying module can dynamically activate or deactivate specific output stages to match the current operating conditions, enabling smooth transitions that maintain voltage stability while optimizing power consumption.
Data Source
AI summary
A simultaneous low quiescent current and high performance low dropout (LDO) voltage regulator is disclosed. In some implementations, the LDO voltage regulator includes a first and a second pass transistors configured to receive an input voltage (Vin). The LDO voltage regulator further includes an error amplifying module having a first output, a second output, a first input, and a second input. The error amplifying module can further include a first output stage configured to drive the gate of the first pass transistor during a high performance (HP) mode, and a second output stage configured to drive the gate of the second pass transistor during the HP mode and during a low power (LP) mode.