Return-Path: X-Spam-DCC: paranoid 1290; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, FORGED_RCVD_HELO,SUBJ_RE_NUM autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id t7AFWp8N025795 for ; Mon, 10 Aug 2015 17:32:51 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ZOp1k-0005BZ-45 for rs_out_1@blacksheep.org; Mon, 10 Aug 2015 16:30:16 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ZOp1j-0005BQ-S4 for rsgb_lf_group@blacksheep.org; Mon, 10 Aug 2015 16:30:15 +0100 Received: from smarthost01c.mail.zen.net.uk ([212.23.1.5]) by relay1.thorcom.net with esmtp (Exim 4.86) (envelope-from ) id 1ZOp0f-0002dH-Oc for rsgb_lf_group@blacksheep.org; Mon, 10 Aug 2015 16:30:14 +0100 Received: from [82.70.254.222] (helo=OfficeWin7.lan) by smarthost01c.mail.zen.net.uk with esmtp (Exim 4.80) (envelope-from ) id 1ZOp0P-0004yM-VC for rsgb_lf_group@blacksheep.org; Mon, 10 Aug 2015 15:28:54 +0000 Date: Mon, 10 Aug 2015 16:28:53 +0100 From: Chris Wilson Organization: Gatesgarth Developments X-Priority: 3 (Normal) Message-ID: <1407871247.20150810162853@chriswilson.tv> To: Andy Talbot In-Reply-To: References: <1892164761.20150810130954@chriswilson.tv> <7E7DFBB4D102A04DB5ADC88D66628A4A443E0BC1@ICTS-S-MBX1.luna.kuleuven.be> MIME-Version: 1.0 X-Originating-smarthost01c-IP: [82.70.254.222] X-Scan-Signature: 64437c466041e93ffedda7fb96b22b71 Subject: Re[2]: LF: Protecting a MOSFET driver chip from MOSFET failure? Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 3847 Hello Andy, Monday, August 10, 2015 > No, capacitive coupling with diode restorationends up with > near-enough  the same voltage applied to the gate as you had in thr first place. > A 0/12v output from the driver chips ends up at -0.7 /+ 11.3 V (assuming 0.7V diode drop) > As for the question of the dual drive with resistors.    The > resistors may as well say in, just to smooth off edges and reduce > dissipation in the driver.     i doubt you'll notice any difference. > Andy  G4JNT OK, thanks and sorry for the naive questions, lots to learn, I was amused by my friend calling power FET's "Fire Emitting Transistors". I see his point now, they do go with a good bang and sizzle! The wife smelt them downstairs and asked wearily if it meant a longer wait before a job she attached great importance to, but I classed as a boring irrelevance, got done... -- Best regards, Chris mailto:chris@chriswilson.tv