Programmable LDO Regulator With Overshoot and Phase Margin Control
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Solution Overview
Problem
Equipment front-end modules (eFEMs) require ultra-low off-state current, fast wake-up times, and on-die electronic fuse trimming for high product yield, which existing LDO voltage regulators struggle to meet.
Innovation Solution
A programmable output low-dropout (LDO) voltage regulator with power supply ramping overshoot control and programmable phase margin optimization, incorporating a coupling circuitry, overshoot control module, and bandgap voltage source to stabilize output voltage and optimize phase margin across varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LDO voltage regulators are used, then basic voltage regulation is achieved, but ultra-low off-state current, fast wake-up times, and programmable output voltage cannot be met
Solution Approach 1:
The LDO regulator employs dynamic element sizing where transistors W1-W4 have width-to-length ratios that are integer multiples of a base ratio, allowing programmable output voltage through different activation combinations. The circuit dynamically switches between different transistor configurations to achieve both ultra-low leakage current and programmable voltage output, resolving the contradiction between fixed performance and adaptability.
2Speed
If power supply ramping occurs, then voltage transition is enabled, but output voltage overshoot is generated
Solution Approach 1:
The circuit applies preliminary anti-action through transistors W5-W8 and resistors R1-R2 that are configured to counteract overshoot before it occurs. During power supply ramping, these elements pre-position the circuit state to prevent excessive voltage rise, enabling fast transition while suppressing harmful overshoot through proactive compensation rather than reactive correction.
Solution Approach 2:
The LDO incorporates feedback mechanisms where the output voltage is monitored and fed back through the error amplifier to adjust the pass transistor gate voltage. This feedback loop detects early signs of overshoot during ramping and automatically corrects the control signal to maintain stable output, resolving the contradiction between fast transition and overshoot suppression.
3Stability of the object's composition
If phase margin is optimized for stability, then regulation accuracy improves, but response speed decreases
Solution Approach 1:
The circuit changes parameters dynamically by adjusting the effective compensation capacitance and resistance values based on operating conditions. The transistor sizing ratios and resistor values are designed to provide optimal phase margin at different load and voltage conditions, allowing the system to maintain both stability and fast response by adapting parameters rather than fixing them.
Data Source
AI summary
A low-dropout (LDO) voltage regulation circuit comprises a first supply voltage, a first transistor, an overshoot control module, and coupling circuitry configured to couple the first supply voltage, the transistor, and the overshoot control module at a first node.