>-----Original Message----- >From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] >On Behalf Of Bob Axtell >Sent: 31 October 2007 15:13 >To: Microcontroller discussion list - Public. >Subject: Re: [EE] Amplified diode regulator > > >David VanHorn wrote: >>> I was thinking about regulating the Vdd using an amplified diode >>> circuit. Basically the input voltage could be varied between 4-7.2V >>> and I am going to set this circuit to 3.3V. The load is >around 1-2mA. >>> I was wondering if there is any con about this? >>> >> >> As shown, this is not a regulator. >> I think what you're intending is an emitter follower on a zener >> regulator, but a single component monolythic solution would be much >> better, and probably more efficient as well. >> >I think his verbiage is correct, tho... he is amplifying a >zener diode. >At 2mA you could use a 3.3V >zener by itself, methinks. An amplified diode can use Vbe to do the regulating. A potential divider connected accross the collector and emitter feeds a fraction of Vce to the base, thus you get some multiple of Vbe appearing accross Vce (the OP's circuit is not quite correct). A fairly low performance circuit anyway. Regards Mike ======================================================================= This e-mail is intended for the person it is addressed to only. The information contained in it may be confidential and/or protected by law. If you are not the intended recipient of this message, you must not make any use of this information, or copy or show it to any person. Please contact us immediately to tell us that you have received this e-mail, and return the original to us. Any use, forwarding, printing or copying of this message is strictly prohibited. No part of this message can be considered a request for goods or services. ======================================================================= -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist