Solid State relay Very high current >50-100 Amps 3-5 VDC form "C" MBB ("D ") - Page 1
Forum section: electronics / projects

author: HCT203
author_rank: Newbie
timestamp: October 16, 2017, 04:52:58 am
content: Seeking help in finding a source or maybe designing a high current solid state relay SPDT > 50-100 ADC form " D" it is essentially a form "C" EXCEPT MBB ( make before break ) working voltage 3-5 Vswitching speed < 10 msec rep rate less than 5/minutes or every 12 second . seeking very low ON impedance ( Less than 2 milliohms )Willing and able to compensate anyone helping me in solving successfully this requirement .Please do not underestimate this project will require serious solid state relay experience as well very strong FET Gate driving design skill,Looking to use HT0440 by Microchip , as well as sub-milliohm Power MosFET such as IRF1324S-7PPbF or IPT004N03L .

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 16, 2017, 07:14:56 am
content: Gate charge is going to be more than you'll want to drive with a PV array (or whatever that thing is; maybe a charge pump, actually).Load: capacitive, resistive, inductive? Mixed? Any transients?How much power is available? Must it be strictly logic-level, or is a DC supply available?How about the nature of the isolation: is it actually common ground, or floating with a modest compliance range? Or does it need 400V or more of transient or continuous isolation? Is it actually, say, 250VAC continuous but then also exposed to mains transients?I think I'd be more inclined to use a transformer or DC-DC converter for drive, and target a switching speed in the 1ms range. This will have less risk of damaging transistors during switching. A large TVS can be added across the transistors if heavily inductive loads must be switched. Current limiting (fault protection) may be a knock-on bonus for not much added cost.What about budget, timeline, and estimated production rate?Tim

author: HCT203
author_rank: Newbie
timestamp: October 16, 2017, 06:05:05 pm
content: Good afternon , TimReally appreciate your response , it is clear you know what you are talking,I looking to use the HT0440 , for several reasons 1) isolation , 2 ) have experience with it 3) have about 10,000 in stock , 4) fairly cost effective gate driver 5) rather not use additional power source cost , space and reliability reason .The HT0440 when used in a form "C" arrangement with 4 FETs to creating the N.C. Common and N.O contacts , the circuit pretty much does what we are seeking Solid State relay form " D" make before break this is accomplished by the much longer turn off time than the turn on time of he HT0440 please take a long a the specification of the part and some fairly decent application notes from Microchip.It function fairly well with low Gate charge FET , less than 600 picofarad , trying to figure out how to store the charge on a outside cap before dumping into the gate ounce the switch comment is initiated ( have no probleme waiting a couple second after command to do actual switching from NC to NO , what is important that we have MBB , working with DC , could be high voltage , and inductive .The idea is to never open the circuit , but change the impedance value.from 2X to X ( example 4 milliohms to 2 milliohms using 4 FET ),

author: jumpshowhigh
author_rank: Newbie
timestamp: October 17, 2017, 07:30:49 pm
content: http://www.perfectswitch.com/

author: henryinsydney
author_rank: Contributor
timestamp: January 01, 2018, 01:32:18 am
content: Interesting products there at "perfectswitch". I've used 4 MOSFETs in parallel for that, two for one direction, two for the other, driven by an LTC1255 high side driver.