MEMS Sensor Power-Domain Switching for Low-Leakage Power-Down

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Solution Overview

Problem

MEMS sensor devices in low-power applications face significant power consumption issues due to leakage currents in inactive states, particularly in the electronic circuitry, which are not effectively managed by existing multi-domain approaches that increase circuit complexity and require external control.

Innovation Solution

Implementing a microelectromechanical sensor device with two distinct voltage domains: an always-on core and a selectively switchable second domain, where the second domain is powered by a voltage regulator and can be switched off in a deep power-down condition, minimizing power consumption to a few tens of nA, and transitioning to a soft power-down condition to reduce leakage currents further.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If power supply switches are implemented externally to reduce power consumption, then power saving is improved, but circuit complexity and size occupation increase

Engineering Contradiction:

Improvepower consumptionVSAvoidcircuit complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent merges the power supply switch control logic directly into the sensor device's internal circuitry, specifically within the analog-to-digital converter (ADC) and voltage regulator infrastructure. This integration eliminates the need for external power supply switches and their associated control circuits, thereby reducing overall circuit complexity while maintaining the ability to selectively power different operational domains of the sensor device.

Inventive Principle:

Principle #5Merging (Combining)

2Use of energy by moving object

If power supply switches are implemented externally to reduce power consumption, then power saving is improved, but size occupation increases

Engineering Contradiction:

Improvepower consumptionVSAvoidsize occupation

Core Design Contradiction:

Use of energy by moving objectVSArea of stationary object

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If control logic is implemented in digital part to manage power supply switches, then power management capability is improved, but power consumption increases in power-down condition

Engineering Contradiction:

Improvepower management capabilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent segments the sensor device into multiple independent power domains, each with its own power supply switch and control logic. The digital part is divided into domains that can be independently powered on or off. This segmentation allows the control logic to manage power supply switches for specific domains without requiring the entire digital part to remain powered, thereby reducing overall power consumption in power-down conditions while maintaining power management capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements periodic power cycling of different operational domains within the sensor device. Instead of keeping the entire device continuously powered, the system periodically activates only the domains needed for current operations and deactivates others. This periodic action reduces average power consumption while maintaining the ability to quickly activate required functions when needed.

Inventive Principle:

Principle #19Periodic action

4Use of energy by moving object

If multi-domain approach is used to reduce power consumption, then power saving is improved, but device complexity increases

Engineering Contradiction:

Improvepower consumptionVSAvoiddevice complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentEP4390623B1Microelectromechanical sensor device with improved management of a power-down condition

Publication Date: 2025.06.25 STMICROELECTRONICS INT NV

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AI summary

A microelectromechanical sensor device (1) has a detection structure (66) and an associated electronic circuitry (2), configured to receive, when the device is powered, an external power supply voltage (VDD) and provided with a voltage regulator (8) generating a regulated voltage (VREG) and with at least one voltage domain (6) powered by the regulated voltage. The electronic circuitry has a power supply management core (10), always powered by the external power supply voltage and which controls the voltage regulator to selectively interrupt the power supply of the voltage domain to implement: a first power-down condition wherein the voltage regulator is disabled; and a second power-down condition wherein the voltage regulator is enabled to power the aforementioned voltage domain through the regulated voltage, the first and the second power-down conditions being associated with absence of data acquisition by the sensor device. The power supply management core automatically enables the first or second power-down condition upon a first power-on of the sensor device, as a function of a configuration signal (Sconf), programmable, for example, during a factory calibration step.