Path: ...!news.mixmin.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Phil Hobbs Newsgroups: sci.electronics.design Subject: Re: Designs Date: Thu, 9 May 2024 02:31:11 -0000 (UTC) Organization: A noiseless patient Spider Lines: 36 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Injection-Date: Thu, 09 May 2024 04:31:11 +0200 (CEST) Injection-Info: dont-email.me; posting-host="e32ac61c3fa108018fad465cdface15e"; logging-data="456161"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18ewQIweQz0Qup9o+LfrWia" User-Agent: NewsTap/5.5 (iPhone/iPod Touch) Cancel-Lock: sha1:aW/JT8vT4DFHZb42eQaU3HMGOdw= sha1:cg3oVK7x0sMMX86MFlOhHuuwJIw= Bytes: 2314 Edward Rawde wrote: > "john larkin" wrote in message > news:imvn3jt2fmc579svih93qvj54o41rabc60@4ax.com... >> On Wed, 8 May 2024 20:10:48 -0000 (UTC), jim whitby >> wrote: >> >>> Somebody neds to post a design... so here's one! >>> >>> https://imgs.xkcd.com/comics/circuit_diagram.png >> >> https://www.dropbox.com/s/w8px8z9mf64wpc9/HVamp.JPG?raw=1 >> > > Reminds me of audio amps which used an op amp's supply pins for the upper > and lower drive. > > > That’s a pretty mainstream technique actually. It’s a lot easier to stabilize if the op amp has good supply rejection—lots don’t, especially on the negative side. In the last dozen years or so, AD and TI have come out with a lot of great 36V op amps, but for several years before that, they were dropping lots of good old HV parts such as the LF357 and AD743 , and only introducing 5-V ones. Using the supply pins to drive a Class B output stage lets you use LV parts for higher-voltage applications. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics