Electronic Fuse Standby Circuit for Low Battery Current Drain

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Solution Overview

Problem

Electronic fuses in automotive power distribution systems face challenges in managing current absorption during standby states, leading to increased energy consumption and reduced battery life due to the inability to completely switch off the current, which complicates their use in applications requiring prolonged standby operations.

Innovation Solution

A current absorption management circuit with an integrated secondary switch, controlled by a low-current consumption driver, allows for an ON standby state that can be entered via direct microcontroller command, featuring load current detection for automatic deactivation and reactivation, thereby minimizing current drain during quiescent states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If an electronic fuse operates in ON state to supply current to load, then the load receives power, but current is continuously consumed even during standby states

Engineering Contradiction:
Improvecurrent consumptionVSAvoidstandby operation capability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The electronic fuse implements dynamic operation by transitioning between three states: full ON state for normal operation, OFF state for complete disconnection, and a novel ON standby state with controlled minimal current. This dynamic state management allows the system to adapt current consumption to actual load requirements, enabling prolonged standby operation without excessive battery drain.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the current parameter from a fixed binary state (fully ON or fully OFF) to a variable state that can be precisely controlled. By adjusting the current magnitude to a minimal level during standby while maintaining the ON state, the system achieves both low power consumption and operational readiness, resolving the contradiction between energy use and reliability.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the electronic fuse is switched to OFF state to reduce current consumption, then energy saving is achieved, but the system cannot quickly resume full operation

Engineering Contradiction:
Improveenergy savingVSAvoidswitching response speed
Core Design Contradiction:
Loss of energyVSSpeed

Solution Approach 1:

The system enters an ON standby state that serves as a preliminary intermediate condition between full operation and complete shutdown. This preliminary state maintains the circuit in a ready configuration with minimal current flow, allowing instant transition to full power when needed, thus avoiding the delay associated with cold startup from complete OFF state.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The electronic fuse implements periodic or on-demand transitions between operational states based on system requirements. The ability to quickly switch between ON standby and full ON states creates a flexible response pattern that minimizes energy loss while ensuring rapid availability when load demand arises.

Inventive Principle:
Principle #19Periodic action

3Reliability

If a small current flows to load during standby state, then the electronic fuse remains functional, but overall current consumption increases

Engineering Contradiction:
Improvefunctional readinessVSAvoidcurrent consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The invention applies local quality by differentiating current magnitude across different operational contexts. During standby, a localized minimal current is supplied to maintain functional readiness of critical components, while the overall system current consumption is kept very low. This selective current distribution achieves both reliability and energy efficiency.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system applies partial action by supplying only the minimal necessary current during standby state - enough to maintain functional readiness but insufficient to drive full load operation. This partial current supply optimizes the balance between maintaining reliability and minimizing energy consumption.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4012866B1Current absorption management circuit, corresponding system and method
Publication Date: 2023.12.27 STMICROELECTRONICS SRL
  • EP4012866B1 patent drawingFigure 1
  • EP4012866B1 patent drawingFigure 2
  • EP4012866B1 patent drawingFigure 3

AI summary

A current absorption management circuit (10) for use in an electronic fuse, for instance, comprises a first node (VBAT+) and a second node (OUT) coupled to an electrical supply source (for instance a battery SS in a motor vehicle V) and an electrical load (L) supplied by the electrical supply source (SS) via an electronic switch (such as a power MOSFET transistor 12) having a control node). A third node (GD) of the circuit is coupled to the electronic switch (12) to switch the electronic switch (12) between a conductive state (1000), wherein the electrical load (L) is coupled to the supply source (SS) via the electronic switch (12), and a non-conductive state (1000A). A secondary electronic switch (12A) is arranged intermediate the first node (VBAT+) and the second node (OFF) and control logic circuitry (20) is provided configured to operate alternately: in a first (full ON) mode of operation (1000), wherein the electronic switch (12) is in a conductive state and the electrical load (L) is coupled to the supply source (SS) via the electronic switch (12), and the secondary electronic switch (12A) is in a non-conductive state, and in a second (ON active-standby) mode of operation (1002), wherein the electronic switch (12) is in a non-conductive state and the secondary electronic switch (12A) is in a conductive state and the electrical load (L) is coupled to the supply source (SS) via the secondary electronic switch (12A).