Load Driving Device Overvoltage Protection Circuit
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Solution Overview
Problem
Load driving devices face challenges in withstanding destructive testing without increasing the withstand voltage of components, leading to potential smoking or destruction, and existing solutions either require larger components or additional external protection, increasing costs.
Innovation Solution
A load driving device with an internal circuit, output circuit, fault detection circuit, and power switches that monitor supply voltages and disconnect power when faults are detected, allowing for overvoltage protection without increasing component withstand voltage, using a fault detection signal to manage supply voltage feed lines and transistor gates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the withstand voltage of the output device is raised to withstand overvoltage destruction testing, then the reliability during destructive testing is improved, but the chip area increases due to larger component size
Solution Approach 1:
The patent divides the protection function into two parts: the output device maintains its original rated voltage specification, while a separate overvoltage detection circuit monitors for overvoltage conditions and triggers a protection mechanism. This segmentation allows the output device to remain small while the system as a whole gains overvoltage withstand capability.
Solution Approach 2:
The patent introduces an overvoltage detection circuit as an intermediary between the power supply and the output device. This intermediary monitors the supply voltage and activates protection switches when overvoltage is detected, thereby protecting the output device without requiring it to have higher inherent withstand voltage and larger size.
2Reliability
If additional external protection components are added to provide overvoltage protection, then the reliability during destructive testing is improved, but the product cost increases
Solution Approach 1:
The patent merges the overvoltage protection function with the existing load driving device by integrating the overvoltage detection circuit and protection switches into the same chip. This integration eliminates the need for separate external protection components, thereby maintaining reliability while reducing product cost and simplifying manufacturing.
Solution Approach 2:
The patent makes the load driving device universal by giving it dual functionality: normal load driving operation and overvoltage protection. The integrated protection circuit serves multiple purposes by monitoring supply voltage and protecting against overvoltage conditions, eliminating the need for separate dedicated protection components.
Data Source
AI summary
A load driving device according to the present invention has: an internal circuit (DRV) that operates in response to the supply of a power supply voltage (HV or LV); an output circuit (PD1 and PD2) for driving a load in response to the supply of the power supply voltage (HV or LV); an abnormality detection circuit (12) for monitoring the power supply voltage (HV or LV) and generating an abnormality detection signal (S1); and a power supply switch (P0) for, according to the abnormality detection signal (S1), conducting or cutting off a power-supply-voltage supply line to the internal circuit (DRV).