This thread has been locked.
If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.
My application is intended towards drilling holes by the help of Spark (it is known as Electric Discharge Machining). I am using DC Power Supply of 300V, 10A range and the -ve terminal of which I am switching using MOSFET circuit, which then gets connected to the tool and workpiece is connected to +ve terminal of a power supply. As soon as we bring the two electrodes (tool & workpiece) close to each other, sparks occurs. So I need to sense the current and voltage that changes during spark / short circuit, using some Sensing Modules having voltage and current range we have.
Kindly suggest the better solution.
Also i need to buy better Switching MOSFET Modules which can switch high DC Voltages upto 300V upto 1 microsecond or even better.
Also, Protection Circuits for this application, to prevent high flow of current during Short-circuiting and Arcing, which may protect other electronic elements from getting damaged; also needs to be placed.
Are you saying that you will see very fast transients up to 300V when you activate the FET? Our shunt based solutions currently only go up to around 80V in high side configuration, so you would be limited to a low side configuration where the shunt is placed between the load and ground. Would this work for you?
There are other options, the AMC1100 isolated amplifier will support a shunt solution up to 300V (or more), and we also have some magnetic sensing options that are isolated as well (DRV421 and DRV425, for example).
This application looks to me very much like an arc welding application, so maybe you could gain some insight from our welding system design web pages. This may help answer your other questions about MOSFETs and protection circuits. Let us know if that doesn't help you so we can find the right material to get you going, or hook you up with the right people to help you with your design.
Jason Bridgmon, TI Sensing Products Applications Support
Current Shunt Monitor Video Training Series
TI makes no warranties and assumes no liability for applications assistance or customer product design. You are fully responsible for all design decisions and engineering with regard to your products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning your designs.
In reply to Jason Bridgmon:
In our application, we are not looking for any isolated amplifier or shunt based IC. Actually, we are using MOSFETs as a switch. SO our basic concern is that while sparking ,sometimes tool and workpiece come in contact with each other causing short problem. So in that case, the current will rise and voltage drop will be there. So how to handle this problem as increase in current is damaging the MOSFET.
Thus we need to measure / sense the current and voltage too during the case of sparking & shorting, which can handle values of upto 300V.
In reply to Mayank Srivastava:
Correct me if I've misinterpreted your description but I think the attached circuit will help you monitor both the wide-band current and voltage signals at the output of your 300V source.
The current sense circuit is described in detail in this application note. The INA138 or INA168 can be used in this circuit for their high bandwidths (800kHz typical in gain of 1 configuration) and should get you close to your target requirement.
For voltage measurement you will have to attenuate the common-mode signal to fit within the input CM range of the op amp that you select. We have a wide range of op amps suitable for various supply voltage constraints. So what other supply voltages does your system have besides the 300V supply?
Getting Started with Current Sensing Video Training Series
Hall Effect Training Resources
In reply to Harsha Munikoti:
Just wanted to check back with you on whether you were able to find a solution to your problem. We are here to help if you need further support.
All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with respect to these materials. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.
TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs andembedded processors, along with software, tools and the industry’s largest sales/support staff.