High Current ESK8 Switch - Repair Help - Page 1
Forum section: electronics / repair

author: vitormhenrique
author_rank: Unknown
timestamp: August 21, 2016, 05:39:55 am
content: Hello Everyone,So I think I fried my High Current ESK8 Switch when I turned it on when my ESC was shorted. It was supposed to handle up to 120 amps (which I doubt it would) but now it's on all the time. I'm having problems identifying the following components (I'm just a hobbyist, so please don't be mad if it is too obvious). I searched the part numbers on digikey and findchips.com without success.I'm pretty sure that they are some sort of BJTs, FETs and MOSFETs, but which? What package is this one? The switch is supposed to handle up to 60V and 120A do you guys know replacement parts that I could use?I tried to reverse engineer the schematics, picture attached, but I could not understand the highlighted area, why is it necessary for the circuit to work? What is it doing?I also have another question, my ESC can use the energy generated by the motor when braking to charge the battery, but, can the switch handle the reverse current?Thank you so much for the help

author: singapol
author_rank: Frequent Contributor
timestamp: August 21, 2016, 01:20:16 pm
content: They are all mosfets N and P channel. BV is the company's "logo".At least they use a recognisable namingsystem for mosfets. 4N15 can mean 4= 4A (ampere) N =N channel 15 = 150V or 1500V. Same for P channel, the P in the 2nd. mosfet in the picture is now an "F"..haha. The 3rd. mosfet is probably 2SK2711 to3p package through hole big size.The surface mount package here is also known as D2PAK, TO263 or TO220S (smt technology). So a close equivalent of 2SK3711 could be IRF2805S by Infineon. Note 2SK3711 drain current is rated over 100A.RC model/drone motors need such power.PS I think your drawing is incorrect? The N and P channel could be doing push pull duty. Search online for example circuits.https://en.wikipedia.org/wiki/TO-263http://www.electronics-component.com/product-detail/2SK3711/358658.html

author: amyk
author_rank: Super Contributor
timestamp: August 21, 2016, 01:32:40 pm
content: Quote from: singapol on August 21, 2016, 01:20:16 pmNice try, but no.http://www.aosmd.com/products/mosfets/n-channel/AOB260Lhttp://www.aosmd.com/products/mosfets/n-channel/AOB2608LThe logo is in the top left. The part number is on the right. The bottom line is the date code.

author: singapol
author_rank: Frequent Contributor
timestamp: August 21, 2016, 01:49:12 pm
content: Quote from: amyk on August 21, 2016, 01:32:40 pmYou are right I thought opposite that the markings above were batch code.By "logo" I meaneach company use a certain prefix to identify their products. I'm aware of the graphic logo which is not very recognisable like other famous brands. A chinese led company?PS: Actually the stated equvalent IRF2805 is a close alternative? I still think the 2nd. line is not the date code.https://www.google.com/finance?cid=4140830

author: vitormhenrique
author_rank: Unknown
timestamp: August 21, 2016, 03:05:10 pm
content: Quote from: singapol on August 21, 2016, 01:20:16 pmYeah, The conections are definetlly correct, but I'not sure if all fets are N type.Quote from: amyk on August 21, 2016, 01:32:40 pmIf all fets are N how does it handle reverse current from the motor to the battery?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 21, 2016, 03:30:27 pm
content: MOSFETs handle reverse current just fine, while on. When they're rated for Rds(on), it's not just because it looks somewhat like a resistor... it's a resistor in both directions, basically for as many amps as the transistor is rated for before something else happens.Even when 'off', the body diode (the arrow in the center of the symbol, often redundantly emphasized by putting a backwards diode in there too) will allow reverse current. Which may be undesirable, because "off" isn't always off!The highlighted circuit limits gate voltage, so that the transistors are safely "on" from about 7V, to more than 20V.Tim

author: vitormhenrique
author_rank: Unknown
timestamp: August 21, 2016, 03:35:27 pm
content: Quote from: T3sl4co1l on August 21, 2016, 03:30:27 pmThank you very much!