Reverse Battery Protection via Substrate Clamping and Power Dissipation Shift
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Solution Overview
Problem
Reverse battery protected devices are vulnerable to catastrophic failure due to excessive power dissipation when batteries are installed in reverse polarity or experience sudden loss, particularly with inductive components, leading to destruction of devices and circuitry, and existing protection methods are costly and inefficient.
Innovation Solution
A method involving a substrate switch with clamping voltages to bias and clamp the substrate during reverse polarity and power loss, shifting power dissipation from vulnerable substrate switches to power switches, using semiconductor substrates and clamping devices to manage power distribution and prevent excessive voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external protection circuits or redesign of affected components are implemented to handle power dissipation during loss of battery, then device reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The power switch automatically assumes the role of protecting the substrate switch during loss of battery by dissipating the inductive power through its own high-power capability, eliminating the need for separate protection circuits. The system uses its existing high-power component to protect the vulnerable low-power component without external intervention.
Solution Approach 2:
The power switch performs its primary function of controlling the inductive load while simultaneously serving as a protection device for the substrate switch during battery failure. This multi-functionality eliminates the need for dedicated protection circuits and reduces overall device complexity.
2Reliability
If external protection circuits or redesign of affected components are implemented to handle power dissipation during loss of battery, then device reliability is improved, but manufacturing cost increases
Solution Approach 1:
The power switch automatically assumes the role of protecting the substrate switch during loss of battery by dissipating the inductive power through its own high-power capability, eliminating the need for separate protection circuits. The system uses its existing high-power component to protect the vulnerable low-power component without external intervention.
Solution Approach 2:
The power switch performs its primary function of controlling the inductive load while simultaneously serving as a protection device for the substrate switch during battery failure. This multi-functionality eliminates the need for dedicated protection circuits and reduces overall device complexity.
3Reliability
If the substrate switch is designed to handle large power dissipation during loss of battery, then device reliability is improved, but component efficiency and cost-effectiveness deteriorate
Solution Approach 1:
The power switch automatically assumes the role of protecting the substrate switch during loss of battery by dissipating the inductive power through its own high-power capability, eliminating the need for separate protection circuits. The system uses its existing high-power component to protect the vulnerable low-power component without external intervention.
Solution Approach 2:
The solution applies different functional requirements to different components: the power switch is designed for high-power handling and is assigned the protection function, while the substrate switch maintains its low-power, high-efficiency design for normal operation. Each component operates in its optimal performance regime.
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 effectively prevents catastrophic failures by distributing power dissipation safely, reducing damage to devices and circuitry, and is more cost-effective than traditional redesigns or external protection circuits, as it shifts the burden to power switches designed for high power handling.
Implementation Method 1
clamping, under loss of power, the substrate of the substrate switch to a second substrate clamping voltage, where an absolute value of the second substrate clamping voltage is less than the absolute value of the first substrate clamping voltage for distributing power
Implementation Method 2
Since voltages across inductive components depend upon the rate of change of current in the component, devices having inductive components typically generate excessively large voltages upon loss of power
Implementation Method 3
biasing, when the device is under reverse polarity, a substrate of a substrate switch of the reverse battery protected device at a negative voltage -Vs, where the voltage Vs of the voltage source is less than an absolute value of a first substrate clamping voltage of the substrate switch so that the substrate switch is non-conducting under reverse polarity
Data Source
AI summary
A system and method for protecting a reverse battery protected device during loss of battery are disclosed. An embodiment method includes biasing a substrate of a substrate switch of the reverse battery protected device to a lowest potential selected between a battery voltage and ground when the battery voltage is less than a magnitude of a first substrate clamping voltage during reverse battery, clamping the substrate to the first substrate clamping voltage when the battery voltage is greater than the magnitude of the first substrate clamping voltage during reverse battery, and clamping the substrate to a second substrate clamping voltage during loss of battery, where a magnitude of the second substrate clamping voltage is less than the magnitude of the first substrate clamping voltage.