Mid-Range LDO Regulator With Internal Reference for Power-Down Mode

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Solution Overview

Problem

Existing semiconductor designs face challenges in efficiently shifting and stabilizing input voltages for core and IO devices within a Safe Operating Area (SOA), particularly in power-down modes where external reference inputs may be absent.

Innovation Solution

A mid-range Low Dropout (LDO) voltage regulator with sinking and sourcing capabilities, incorporating an amplifier, Voltage Reference Generator (VREFGEN), Power-Down Control Unit (PDCTRL), and high-density decoupling capacitors, which dynamically tracks IO and core power to maintain a stable voltage reference within the SOA.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional voltage regulator is used, then voltage stabilization can be achieved, but the device cannot operate in power-down mode without external reference inputs

Engineering Contradiction:

Improveoperational modesVSAvoidcircuit structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The LDO regulator generates its own internal voltage reference through the VREFGEN circuit, eliminating the need for external reference inputs during power-down mode. The circuit serves itself by creating the reference voltage internally rather than requiring external provision, enabling autonomous operation across all power states.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The LDO regulator is designed to function across multiple operational modes including active mode and power-down mode, with the ability to source and sink current. The single circuit architecture handles both voltage regulation and reference generation universally, eliminating the need for mode-specific external components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If high decoupling capacitor density is implemented, then voltage stability improves, but the circuit area increases

Engineering Contradiction:

Improvevoltage stabilityVSAvoidcircuit area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent utilizes Metal-Oxide-Metal (MOM) capacitor technology which achieves high capacitance density by optimizing the physical and electrical parameters of the capacitor structure. This allows obtaining high decoupling capacitance in a reduced area compared to conventional capacitor implementations.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The MOM capacitor employs a composite structure combining metal layers with oxide dielectric materials, creating a high-density capacitive element. This composite approach enables superior capacitance per unit area by leveraging the properties of both conductive metal layers and insulating oxide layers in a vertically stacked configuration.

Inventive Principle:

Principle #40Composite materials

3Loss of energy

If the LDO operates in power-down mode, then power consumption decreases, but voltage reference stability becomes challenging

Engineering Contradiction:

Improvepower consumptionVSAvoidvoltage reference stability

Core Design Contradiction:

Loss of energyVSStability of the object's composition

Solution Approach 1:

The LDO dynamically adapts its operation between active and power-down modes, with the amplifier and control circuitry adjusting their behavior based on the operational state. The internal reference generation circuit remains functional but operates at reduced power levels, maintaining stability through dynamic parameter adjustment rather than static design.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The error amplifier continuously monitors the output voltage and adjusts the pass transistor control accordingly, even in power-down mode. This feedback mechanism ensures voltage reference stability by detecting and correcting any deviations, maintaining regulated output despite reduced power consumption and altered circuit operating conditions.

Inventive Principle:

Principle #23Feedback

4Adaptability or versatility

If the LDO provides both sourcing and sinking capability, then versatility improves, but circuit complexity increases

Engineering Contradiction:

Improvecurrent control capabilityVSAvoidamplifier and control circuit

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The LDO combines both voltage regulation and current sinking capabilities within a single integrated circuit architecture. The error amplifier and control logic are designed to handle both sourcing and sinking operations through unified control mechanisms, eliminating the need for separate dedicated circuits for each function.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12265411B2Low-dropout (LDO) voltage regulator including amplifier and power down control unit (PDCTRL)

Publication Date: 2025.04.01 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A middle-range (mid) low dropout (LDO) voltage has both sinking and sourcing current capability. The mid LDO can provide a voltage reference in active mode and power mode for core only design to work in a Safe Operating Area (SOA). The output of mid LDO can track IO power and/or core power dynamically. The mid LDO can comprise a voltage reference generator and a power-down controller connected to an amplifier, which output is connected to a decoupling capacitor. The provision of a high ground signal allows the mid LDO provide the sinking and sourcing currents.