Efficient Electromagnetic Pulse Driver for Reduced EMI
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Summary
Problems
Classical driver circuits for electromagnetic and electro-permanent magnets in haptic devices dissipate a lot of energy and suffer from Electro-Magnetic Interference (EMI), as they continuously monitor and control current, leading to unwanted oscillations and inefficient energy use.
Innovation solutions
A driver circuit that cuts off the current once it reaches a desired level, using a fast switching circuit with an H-bridge transistor switch and a diode for recirculation, allowing for efficient energy conservation and reduced EMI by maintaining 80% of the capacitor charge for the next pulse.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If continuous current monitoring and control is used, then precise electromagnetic force control is achieved, but energy consumption increases and EMI occurs
Why choose this principle:
The patent implements periodic pulsed current delivery instead of continuous current control. The capacitor charges to a peak voltage and then discharges through the electromagnet in controlled pulses, creating periodic action that reduces average power consumption while maintaining the ability to precisely control electromagnetic force during each pulse cycle
Principle concept:
If continuous current monitoring and control is used, then precise electromagnetic force control is achieved, but energy consumption increases and EMI occurs
Why choose this principle:
The capacitor is pre-charged to a peak voltage before each current pulse is delivered to the electromagnet. This preliminary charging action stores energy in advance, allowing the system to deliver high current pulses without continuous power consumption, thereby reducing overall energy usage while maintaining control precision
Application Domain
Data Source
AI summary:
A driver circuit that cuts off the current once it reaches a desired level, using a fast switching circuit with an H-bridge transistor switch and a diode for recirculation, allowing for efficient energy conservation and reduced EMI by maintaining 80% of the capacitor charge for the next pulse.
Abstract
A driver circuit is provided to connect a charged capacitor through a switch to the inductive windings of an electromagnet for a haptic feedback application. A feedback circuit provides an indication of the current supplied. When the current reaches a desired level, the current is cut off, rather than being controlled. The cutoff level can be slightly below the desired level to allow the desired level to be reached with overshoot. A diode is provided in parallel with the electromagnet winding when the current is shut off, providing a recirculation path that prevents the current from being discharged, thereby dissipating less energy than classical solutions.