Capless Voltage Regulator with Adaptive Compensation for Load Transients

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Capless voltage regulators (CVRs) face challenges in responding quickly and accurately to sudden changes in load demands, often resulting in voltage overshoot or undershoot, particularly as the reference voltage range tightens, leading to increased response times and instability.

Innovation Solution

A quasi-adaptive controller dynamically adjusts the slew rate of the pass device's gate voltage to match the slew rate of the CVR output, using non-linear charging and discharging currents to prevent voltage overshoot and undershoot, enhancing accuracy and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the reference voltage range is tightened to improve voltage regulation accuracy, then voltage regulation precision is improved, but response time increases and stability deteriorates

Engineering Contradiction:
Improvevoltage regulation accuracyVSAvoidresponse time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements dynamic adjustment of the reference voltage range based on operating conditions. The control circuit dynamically selects between a first reference voltage (higher) and a second reference voltage (lower) to adjust the hysteresis window size, enabling the system to adapt between fast response and high precision modes rather than using a fixed reference range

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the reference voltage parameter dynamically to resolve the contradiction. By switching between different reference voltage values, the system adjusts the voltage threshold for triggering the pass device, thereby changing the response characteristics and hysteresis behavior to match different operational requirements

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the reference voltage range is tightened to improve voltage regulation accuracy, then voltage regulation precision is improved, but stability deteriorates

Engineering Contradiction:
Improvevoltage regulation accuracyVSAvoidsystem stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The system dynamically adjusts the reference voltage range based on the operating state, switching between a narrower range for precision and a wider range for stability. This dynamic adaptation prevents the system from operating in a fixed narrow range that would cause instability under varying load conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The reference voltage parameter is changed dynamically to maintain stability. When stability is at risk, the system switches to a higher reference voltage with a wider hysteresis range, which provides greater margin and prevents oscillations, thereby maintaining system stability

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a fixed reference voltage is used to simplify the control circuit, then device complexity is reduced, but the ability to respond to load transients deteriorates

Engineering Contradiction:
Improvecontrol circuit complexityVSAvoidresponse speed to load transients
Core Design Contradiction:
Device complexityVSSpeed

Solution Approach 1:

The patent implements a dynamic reference voltage selection mechanism that automatically adjusts the reference voltage based on detected load conditions. This dynamic behavior enables fast response to transients without requiring a complex multi-reference-voltage design, as the system adapts in real-time rather than requiring pre-configured complex control logic

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control circuit automatically selects the appropriate reference voltage based on its own detection of load conditions, without requiring external control signals or complex external circuitry. The system serves itself by monitoring its own operating state and adjusting the reference voltage accordingly, maintaining simplicity while improving response capability

Inventive Principle:
Principle #25Self-service

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 ensures rapid and stable voltage regulation with minimal oscillation, maintaining system stability across varying loads while reducing response time and preventing overshoot or undershoot.

Implementation Method 1

A first capacitor can be connected to a gate of a pass transistor. The first capacitor can be charged by a first biassing circuit

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

The second biassing circuit comprises a precharge capacitor. The precharge capacitor is preloaded with charge. When the load current prediction circuit activates the second biassing circuit, the precharge capacitor is connected to the first capacitor and charges the first capacitor

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 3

An amplifier drives an output stage

Methodology Applied
Scientific EffectElectrical Amplification:

Data Source

PatentEP3979477B1Capless voltage regulator with adaptative compensation
Publication Date: 2025.11.05 NXP USA INC
  • EP3979477B1 patent drawingFigure 1
  • EP3979477B1 patent drawingFigure 2
  • EP3979477B1 patent drawingFigure 3

AI summary

An integrated circuit (IC) is disclosed that includes a load circuit, and a voltage regulator circuit configured to provide a load voltage and a load current to the load circuit. The voltage regulator circuit can regulate the load voltage based on the load current.