Inductive Load Driver Circuit for Fast Magnetic Energy Dissipation
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Solution Overview
Problem
Existing circuit arrangements for driving inductive loads, such as those in motor vehicles, require multiple connections and complex wiring to efficiently dissipate magnetic energy, which increases complexity and wiring harness requirements.
Innovation Solution
A circuit arrangement utilizing a series connection of a reverse-biased zener diode and a forward-biased diode between the drain and gate terminals of a MOS field effect transistor, along with an AND circuit controlling both transistors, allows for quick dissipation of magnetic energy using only one connection to the inductive load and few power switching elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a freewheeling diode is used for dissipation of magnetic energy, then the circuit design remains simple with few components, but the dissipation process takes an undesirably long time
Solution Approach 1:
The patent changes the voltage parameter dynamically by introducing a second supply voltage source with higher voltage than the first. During the dissipation phase, this higher voltage is applied to the inductive load, which increases the rate of magnetic energy dissipation. This parameter change allows fast dissipation without requiring complex additional circuitry, thus resolving the contradiction between simple design and fast dissipation.
2Speed
If multiple MOS field effect transistors and supply voltage sources are used to enable fast dissipation of magnetic energy, then the dissipation speed increases, but the number of components and wiring complexity increases
Solution Approach 1:
The first MOS field effect transistor serves multiple functions: it acts as a switch during the current buildup phase and also functions as a switch during the dissipation phase when controlled by the second control signal. This multi-functionality allows the circuit to achieve fast dissipation using the same transistor that is already present, avoiding the need for additional power switching elements and reducing overall circuit complexity.
3Device complexity
If the inductive load is connected with one connection only, then the wiring harness requirements are reduced, but the ability to quickly dissipate magnetic energy is compromised
Solution Approach 1:
The patent introduces a temporal dimension to the voltage application by using different supply voltage sources at different time phases. During the dissipation phase, the higher second supply voltage is applied to the inductive load through the same single connection, effectively adding a voltage dimension that enables fast dissipation without requiring additional physical connections or wiring complexity.
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 configuration enables rapid dissipation of magnetic energy in the inductive load by utilizing the freewheeling diode during the hold phase and the zener diode during turn-off, reducing the number of components and connections needed while maintaining efficient energy discharge.
Implementation Method 1
a series connection comprising at least one reverse-biased zener diode and a forward-biased diode connected up between them
Implementation Method 2
a series connection comprising at least one reverse-biased zener diode and a forward-biased diode connected up between them
Implementation Method 3
the magnetic energy stored in the inductive load dissipates as a result of an induced flow of current via the freewheeling diode
Implementation Method 4
the final dissipation of the magnetic energy stored in the inductive load is possible only by means of a flow of current via the freewheeling diode with its low forward voltage
Data Source
AI summary
A circuit arrangement for driving an inductive load is connectable to a load terminal. A first MOS field effect transistor is connected between a terminal for a high potential of a first supply voltage source and the load terminal. A series connection with a freewheeling diode and a second MOS field effect transistor has its freewheeling diode connected between the load terminal and a second terminal for a low potential of the first supply voltage source. The freewheeling diode has its cathode connected to the load terminal. A series connection with a reverse-biased zener diode and a forward-biased diode is connected between the drain and gate terminals of the first MOS field effect transistor. A first control signal terminal is connected to the gate terminal of the second MOS field effect transistor and via an AND circuit to the gate terminal of the first MOS field effect transistor.