Relay Driver Circuit Using System Basis Chip and Buck Boost Converter
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing driver circuits for relays in battery systems, particularly in automotive vehicles, face issues with complex designs, high costs due to multiple components, and negative EMC performance from large electrolytic capacitors, which affect system lifetime and efficiency.
Innovation Solution
A driver circuit utilizing a system basis chip and a buck boost converter integrated into a single component, eliminating the need for additional PWM signal drives, providing pre-voltage for relay operation and multiple voltage levels, and incorporating diodes and switches for efficient relay control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a PWM signal drive with large electrolytic capacitors is used to drive relays, then the relay can be operated in low power mode, but the system lifetime is reduced due to capacitor aging and degradation
Solution Approach 1:
The patent removes the harmful electrolytic capacitors from the driver circuit by using a MOSFET-based switch circuit that can directly control the relay coil without requiring energy storage capacitors. This extraction of the problematic component eliminates the aging and degradation issues while maintaining the ability to drive the relay in low power mode through pulse width modulation control of the MOSFET gate.
Solution Approach 2:
The patent replaces the traditional capacitor-based energy storage and release mechanism with an electric field-based MOSFET switching mechanism. The MOSFET uses voltage control at the gate to regulate current flow through the relay coil, substituting the mechanical/chemical energy storage of electrolytic capacitors with an electronic field effect device that has no aging electrolyte, thereby improving reliability while maintaining energy efficiency.
2Ease of operation
If a PWM signal drive with multiple components including filters is used, then the relay can be operated, but the design becomes complex and production costs increase
Solution Approach 1:
The patent combines the functions of the PWM signal generator, power switching, and relay control into a single integrated driver circuit using a MOSFET. This merging eliminates the need for separate filter circuits, voltage regulators, and multiple discrete components, thereby reducing design complexity and production costs while maintaining full relay operation capability including low power mode and normal mode switching.
Solution Approach 2:
The MOSFET-based driver circuit is designed to perform multiple functions: it can operate the relay in both normal continuous mode and low power pulse width modulation mode, provide overcurrent protection, and control the relay coil current efficiently. This multi-functionality in a single circuit design reduces the need for additional components and simplifies the overall system architecture.
3Use of energy by moving object
If a PWM signal of 20 kHz is used to drive the relay, then the relay can be operated in economic mode, but the EMC performance of the battery system is negatively influenced
Solution Approach 1:
The patent implements dynamic switching control using the MOSFET's fast switching capability to regulate the relay coil current. By dynamically adjusting the duty cycle of the MOSFET switching, the circuit can operate the relay in low power mode while controlling the frequency and amplitude of current transitions. This dynamic control reduces electromagnetic radiation and switching noise compared to traditional PWM drives, thereby improving EMC performance while maintaining energy efficiency.
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
This solution simplifies the design, reduces production costs, enhances system lifetime, and improves EMC performance by using the system basis chip's pre-voltage to operate relays efficiently in both economic and closed states, while providing safe and efficient voltage levels for microcontrollers.
Implementation Method 1
The driver circuit further includes a buck boost converter including an input and a first output. The input of the buck boost converter is connected to the output terminal of the system basis chip, and the first output of the buck boost converter is electrically connected to the first voltage input.
Data Source
AI summary
A driver circuit configured to control an operation of a relay includes: a voltage output electrically connected with the relay; a first voltage input selectively electrically connected to the voltage output; a buck boost converter including an input and a first output; and a system basis chip including an output terminal connected to the input of the buck boost converter and configured to provide a voltage. The first output of the buck boost converter is electrically connected to the first voltage input.