Power Supply Control Device for Switch Protection
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Solution Overview
Problem
Existing power supply control devices fail to appropriately turn off switches in response to voltage threshold changes, leading to potential damage from excessive current flow and heat buildup due to short circuits, as they cannot differentiate between starter activation and other voltage drops.
Innovation Solution
A power supply control device with a comparison unit and switching unit that turns off the switch when the voltage value of the current input end falls below a predetermined threshold, using a capacitor and resistance configuration to manage voltage and prevent premature shutdowns during disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the potential of the GND terminal is reduced below ground potential to prevent switch turn-off during starter activation, then the switch remains on and power supply to the load continues, but the switch cannot be turned off appropriately when voltage drops occur for other reasons such as short circuits
Solution Approach 1:
The patent applies dynamics by making the GND terminal potential adjustable rather than fixed. The potential control unit dynamically changes the GND terminal potential based on detected voltage drops: reducing it below ground potential during starter activation to maintain power supply, and restoring it to ground potential when voltage drops are caused by other reasons (such as short circuits) to enable appropriate switch turn-off and protect against excessive current and heat.
2Reliability
If the voltage threshold is set to detect voltage drops for switch turn-off, then the switch can be turned off when voltage drops occur, but the switch may be turned off inappropriately during normal starter activation
Solution Approach 1:
The patent applies feedback by using the voltage detection unit to continuously monitor voltage drops and feed this information to the potential control unit. The potential control unit then adjusts the GND terminal potential in response to the detected voltage drop characteristics, creating a closed-loop control system that distinguishes between starter activation (where the threshold should not trigger turn-off) and other voltage drops (where turn-off is appropriate), thereby improving switch control accuracy while maintaining power supply efficiency.
Data Source
AI summary
A power supply control device includes a switch disposed in a first current path of a current flowing from a battery. A first comparator compares a voltage value of a current input end of the switch to which the current is inputted with a voltage threshold. When the voltage value of the current input end is less than the voltage threshold, a drive circuit turns off the switch. The battery supplies, via a second current path, power to a starter that starts an engine of a vehicle. The voltage threshold is less than the voltage value of the current input end of the switch in the case where the battery supplies the power to the starter.