Design Goals
Nominal Current | Overcurrent Level | High-Side Supply | Low-Side Supply | Transient Response Time |
---|---|---|---|---|
50 A | 55 A | 3 V–27 V | 2.7 V–5.5 V | ≤ 1000 ns |
Design Description
This high-speed, isolated bidirectional overcurrent detection circuit is implemented with the AMC23C12. The AMC23C12 features an isolated window comparator and an adjustable threshold level via a fixed internal precision current source and user-selectable resistor. This circuit is designed for fast detection of overcurrent situations allowing the controller to disable pulse width modulation (PWM) control of high-speed switches used in motor control, traction inverter, and other industrial control systems.
Design Notes
Design Steps
Design Simulations
The following images are SPICE simulations of the overcurrent protection circuit. The simulations show the time until the edges trigger which is approximately 360 ns.
Design Results
The following images are the waveform captures of the physical circuit. Overcurrent Protection Circuit Waveform shows the output on line 1 with relation to input on line 3. Overcurrent Protection Circuit Waveform - Rising shows the rising edge of the output line 1 and the time delay from the triggered current to the output. Overcurrent Protection Circuit Waveform - Falling shows the falling edge of the output line 1 and the time delay from the triggered current to the output.
Design Featured Devices
Device | Key Features | Device Link |
---|---|---|
AMC23C12 |
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Device: AMC23C12 Similar Devices: Isolated amplifiers |
Design References
See Analog Engineer's Circuit Cookbooks for TI's comprehensive circuit library.
Texas Instruments, AMC23C12 Fast Response, Reinforced Isolated Window Comparator With Adjustable Threshold and Latch Function data sheet
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