Path: ...!news.mixmin.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: piglet Newsgroups: sci.electronics.design Subject: Re: Another design Date: Fri, 10 May 2024 21:26:11 +0100 Organization: A noisesome patent Spinner Lines: 207 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Fri, 10 May 2024 22:26:12 +0200 (CEST) Injection-Info: dont-email.me; posting-host="4daac1e766a33a5176c37d6d6e936f3a"; logging-data="1642782"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18g7Y18pzuNwXg1H8Jh6wRC" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:jSqS/l8zx0NMkCgJ5luLm8Sc7hQ= Content-Language: en-GB In-Reply-To: Bytes: 6562 On 10/05/2024 7:57 pm, Edward Rawde wrote: > "piglet" wrote in message > news:v1li00$1eir3$1@dont-email.me... >> On 10/05/2024 4:11 am, Edward Rawde wrote: >>> "Edward Rawde" wrote in message >>> news:v1ho21$4ps$1@nnrp.usenet.blueworldhosting.com... >>>> Now with 9V to 15V input range, direct gate drive and 500mA LED current. >>>> >>>> Startup behaviour is not ideal but maybe that can be fixed if it needs >>>> fixing. >>>> >>>> What's the cheapest op amp I can use for U2 instead of OP07? >>>> >>>> Is there a cheaper comparator instead of LT1719 which will work? >>>> Also the fet is bigger than it needs to ne. >>>> >>>> Is there a better device for D4? Particularly if R4 can be reduced. >>>> >>>> Will it work at all? Except in simulation. >>>> >>> >>> I think I've answered my own question for the current controller but I >>> don't >>> think it's feasible to attempt a discrete comparator on cost grounds. >>> > ... >> >> >> The venerable LM311 is still a good value comparator, if you want to penny >> pinch omit the gate driver buffers and lower the pullup resistor but >> efficiency will drop a lot from 85% to ca 72%. >> > > Thanks, that works but I was hoping for a smaller inductor at about 1MHz and > filtered LED feed referenced to ground for up to three LEDs. > > I'm probably done with my circuit unless there's a cheaper comparator which > can do the same job or a cheaper op amp which can run on lead acid voltage. > Or preferably up to 15V. > Also a cheaper fet. > > Ground referenced output is possible, rearrange the sense resistor and stand the reference on top of the LEDs. As in ... Version 4 SHEET 1 996 708 WIRE -544 -112 -704 -112 WIRE -48 -112 -544 -112 WIRE 48 -112 -48 -112 WIRE 192 -112 48 -112 WIRE 336 -112 192 -112 WIRE 48 -96 48 -112 WIRE 192 -48 192 -112 WIRE -544 -16 -544 -112 WIRE 48 0 48 -16 WIRE 128 0 48 0 WIRE 336 64 336 -112 WIRE 192 80 192 48 WIRE 288 80 192 80 WIRE -544 176 -544 64 WIRE -448 176 -544 176 WIRE -240 224 -288 224 WIRE 336 224 336 160 WIRE 336 224 -160 224 WIRE -448 240 -448 176 WIRE 336 272 336 224 WIRE 416 272 336 272 WIRE 528 272 496 272 WIRE 624 272 528 272 WIRE -704 320 -704 -112 WIRE 528 320 528 272 WIRE 528 320 400 320 WIRE 624 320 624 272 WIRE -160 336 -192 336 WIRE -48 336 -48 -112 WIRE -48 336 -80 336 WIRE -544 352 -544 176 WIRE -48 384 -48 336 WIRE 192 384 192 80 WIRE -448 416 -448 320 WIRE -288 416 -288 224 WIRE -288 416 -448 416 WIRE -80 416 -288 416 WIRE 48 432 48 0 WIRE 48 432 0 432 WIRE 128 432 48 432 WIRE -192 448 -192 336 WIRE -80 448 -192 448 WIRE 480 448 432 448 WIRE 624 448 624 400 WIRE 624 448 480 448 WIRE -448 464 -448 416 WIRE 336 464 336 272 WIRE 624 480 624 448 WIRE -192 496 -192 448 WIRE 480 496 480 448 WIRE -544 560 -544 416 WIRE -448 560 -448 544 WIRE -448 560 -544 560 WIRE -704 592 -704 400 WIRE -64 592 -64 480 WIRE -64 592 -704 592 WIRE -48 592 -48 480 WIRE -48 592 -64 592 WIRE 192 592 192 480 WIRE 192 592 -48 592 WIRE 336 592 336 528 WIRE 336 592 192 592 WIRE 480 592 480 560 WIRE 480 592 336 592 WIRE 624 592 624 544 WIRE 624 592 480 592 WIRE -704 640 -704 592 WIRE -192 672 -192 576 WIRE 400 672 400 320 WIRE 400 672 -192 672 WIRE -448 688 -448 560 WIRE 432 688 432 448 WIRE 432 688 -448 688 FLAG -704 640 0 SYMBOL schottky 352 528 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D1 SYMATTR Value 1N5817 SYMATTR Description Diode SYMATTR Type diode SYMBOL ind 400 288 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 5 56 VBottom 2 SYMATTR InstName L1 SYMATTR Value 0.22m SYMATTR SpiceLine Rser=50m SYMBOL LED 608 480 R0 SYMATTR InstName D2 SYMATTR Value LXK2-PW14 SYMATTR Description Diode SYMATTR Type diode SYMBOL voltage -704 304 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value 12 SYMBOL res 608 304 R0 SYMATTR InstName R8 SYMATTR Value 0.15 SYMBOL zener -528 416 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D3 SYMATTR Value 1N750 SYMATTR Description Diode SYMATTR Type diode SYMBOL res -560 -32 R0 SYMATTR InstName R1 SYMATTR Value 2k SYMBOL res -464 448 R0 SYMATTR InstName R3 SYMATTR Value 100 SYMBOL res -464 224 R0 SYMATTR InstName R2 SYMATTR Value 4.3k SYMBOL res 32 -112 R0 SYMATTR InstName R7 SYMATTR Value 10k SYMBOL cap 464 496 R0 SYMATTR InstName C1 SYMATTR Value 0.1m SYMBOL res -144 208 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 33k SYMBOL res -176 592 R180 ========== REMAINDER OF ARTICLE TRUNCATED ==========