Pre-Charge Relay Drive Circuit Without a Separate Power Supply
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Solution Overview
Problem
Conventional relay driving circuits for semiconductor switching devices require a separate power circuit, leading to increased complexity, area, and cost.
Innovation Solution
A battery system with an integrated relay driving circuit that generates gate voltages for controlling pre-charge and main relays using power from the battery pack, eliminating the need for a separate power circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate power circuit is provided in the relay driving circuit, then the semiconductor switching device can be driven reliably, but the relay driving circuit becomes complicated and the area increases
Solution Approach 1:
The patent merges the power circuit function into the existing relay driving circuit by utilizing the body diode of the MOSFET as a rectifier and the source resistor as a smoothing element. This integration eliminates the need for separate power circuit components while maintaining the ability to provide stable driving power to the MOSFET gate, thereby reducing circuit complexity without sacrificing reliability
Solution Approach 2:
The patent makes existing components serve multiple functions: the source resistor not only provides current limiting and protection but also acts as a power supply smoothing element; the body diode of the MOSFET not only provides protection during reverse voltage conditions but also serves as a rectifier for the power circuit. This multi-functionality reduces the need for additional components and simplifies the overall circuit
2Reliability
If a separate power circuit is provided in the relay driving circuit, then the semiconductor switching device can be driven reliably, but the area of the circuit increases
Solution Approach 1:
The patent combines the power circuit functionality with existing circuit elements, eliminating the need for separate power circuit components that would occupy additional space. The integration is achieved by using the body diode for rectification and the source resistor for smoothing, which reduces the overall circuit area while maintaining reliable MOSFET driving capability
Solution Approach 2:
The patent employs self-service principles where the MOSFET's own body diode and source resistor are utilized to provide power circuit functions. This eliminates the need for external power circuit components, thereby reducing the circuit area while maintaining the ability to drive the MOSFET reliably
3Reliability
If a separate power circuit is provided in the relay driving circuit, then the semiconductor switching device can be driven reliably, but additional costs occur
Solution Approach 1:
The patent merges the power circuit function into the existing relay driving circuit, eliminating the need for separate power circuit components. This integration reduces the bill of materials and assembly complexity, thereby lowering manufacturing costs while maintaining reliable MOSFET driving through intelligent use of existing components
Solution Approach 2:
The patent implements self-service by using the MOSFET's inherent body diode and source resistor to provide power circuit functions. This eliminates the need for additional components that would increase manufacturing costs, while still ensuring reliable operation of the semiconductor switching device
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
Simplifies the relay driving circuit, reduces its area, and lowers costs by utilizing battery pack power to drive relays directly.
Implementation Method 1
a capacitor, and a second transistor, wherein the capacitor is connected between a positive electrode and a negative electrode of the battery pack, and the gate of the pre-charge relay
Implementation Method 2
a Zener diode, wherein the Zener diode is connected in parallel to the second resistor
Data Source
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AI summary
The present invention relates to a relay driving circuit and a battery system for generating a gate voltage for controlling ON/OFF of a pre-charge relay, and provides a relay driving circuit that controls electrical connection between an external device and a battery pack, including: a transistor that receives a control signal of an enable level to perform an ON operation; a first resistor having a first end connected to a positive electrode of the battery pack and a second end connected to the relay, by the ON operation of the transistor; and a second resistor connected between the second end of the first resistor and the external device, the relay receives power supplied from the battery pack in a ratio of a resistance value of the second resistor to a sum resistance value of the first resistor and the second resistor to perform an ON operation.