Battery Protection Circuit Open-Wire Detection With Low-Power Current Sensing

Solution Overview

Problem

Conventional battery protection circuits require an additional current source for open-wire protection, leading to increased power consumption and circuit size due to the disconnection detection circuit.

Innovation Solution

A protection circuit with a current sensing pin coupled to a path node, incorporating a disconnection detection circuit and a first over-current protection circuit, which generates a detection signal to turn off the protection switch when the current sensing pin is disconnected, utilizing a low-current source and resistor configuration to minimize power consumption and circuit area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an additional current source is configured in the pin P6 for open-wire protection, then the disconnection detection function is improved, but the power consumption and circuit size increase

Engineering Contradiction:

Improvedisconnection detection functionVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The current sensing pin P6 is designed to serve dual functions: normal current sensing during battery operation and open-wire protection detection when disconnected. The circuit uses the existing current sensing path to detect disconnection by monitoring voltage changes, eliminating the need for a separate current source dedicated solely to OWP detection.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The disconnection detection circuit utilizes the battery's own operating current and the existing current sensing pin structure to detect disconnection. When the pin is disconnected, the circuit automatically detects the abnormal voltage state and triggers protection without requiring external power sources or additional active components.

Inventive Principle:

Principle #25Self-service

2Reliability

If an additional current source is configured in the pin P6 for open-wire protection, then the disconnection detection function is improved, but the circuit size increases

Engineering Contradiction:

Improvedisconnection detection functionVSAvoidcircuit size

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The current sensing pin P6 is designed to serve dual functions: normal current sensing during battery operation and open-wire protection detection when disconnected. The circuit uses the existing current sensing path to detect disconnection by monitoring voltage changes, eliminating the need for a separate current source dedicated solely to OWP detection.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The open-wire protection detection function is merged with the existing current sensing circuitry. The disconnection detection shares the current sensing pin, associated transistors, and control logic with the normal current sensing function, consolidating multiple functions into a single integrated circuit block.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If a conventional disconnection detection circuit is used, then the open-wire protection is provided, but the power consumption increases by 10-20uA

Engineering Contradiction:

Improveopen-wire protectionVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The disconnection detection circuit utilizes the battery's own operating current and the existing current sensing pin structure to detect disconnection. When the pin is disconnected, the circuit automatically detects the abnormal voltage state and triggers protection without requiring external power sources or additional active components.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The circuit detects disconnection by monitoring changes in voltage parameters at the current sensing pin rather than using a dedicated current source. The detection mechanism transitions from active current injection to passive voltage monitoring, significantly reducing power consumption while maintaining detection capability.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20260025015A1Protection circuit of battery and operating method thereof

Publication Date: 2026.01.22 UPI SEMICON CORP

AI summary

A protection circuit of battery and an operating method thereof are disclosed. The protection circuit of battery has a current sensing pin coupled to a path node. The path node, a battery cell and a protection switch are coupled in series. The protection circuit includes a disconnection detection circuit and a first over-current protection circuit. The disconnection detection circuit is coupled to the current sensing pin and provides a first detection signal. The first over-current protection circuit is coupled to the disconnection detection circuit and generates a first protection signal according to the first detection signal to turn off the protection switch. When the current sensing pin is disconnected from the path node, the first detection signal causes the first over-current protection circuit to generate the first protection signal.