triple switcher
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From: dagmargoodboat on 15 Nov 2009 17:16 On Nov 15, 4:09 pm, John Larkin <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > On Sun, 15 Nov 2009 12:37:31 -0800 (PST), "langw...(a)fonz.dk" > > > > <langw...(a)fonz.dk> wrote: > >On 15 Nov., 19:41, John Larkin > ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > >> On Sat, 14 Nov 2009 13:40:27 -0800 (PST), MooseFET > > >> <kensm...(a)rahul.net> wrote: > >> >On Nov 14, 10:40 am, John Larkin > >> ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > >> >> We keep running into the requirement to turn +12 or +5 volts into 3.3, > >> >> 1.2 (fpga core), and usually a third voltage, 1.8 (for drams) or 2.5 > >> >> (fpga Vccint). We'd like to consolidate this to save board area and > >> >> general complexity. Any suggestions? > > >> >> LTM4615 looks interesting, a bit expensive but very small. > > >> >>http://www.linear.com/pc/productDetail.jsp?navId=H0,C1,C1003,C1424,P8... > > >> >> And other ideas? > > >> >> John > > >> >How about LT3507? > > >> Lots of external parts, schottkies and inductors. > > >> >LT3564 seems to get a lot of switcher into a small package. > > >> We already stock the LTC3407, 3411, and 3412, all similar. But it > >> would be great if somebody did a minimal-parts, minimal-size triple > >> synchronous switcher, ideally with internal inductors. I *told* LTC to > >> do this, and, incredibly, they haven't got around to it. It's not as > >> if FPGAs are losing popularity. > > >> The Spartan 6 parts will run from two supplies (Vccint can run from > >> 3.3) but we want to use a DDR dram, at 1.8 volts, so we're back up to > >> three. > > >something like a ISL65426 and an ldo? > > >-Lasse > > The LTM4615 has all that inside, including the inductors and LDO. That > may be the most compact solution, for $24. > > Still no magic bullet. > > John That LTM4615 looks pretty stinkin' nice--I can think of cheaper ways, and smaller ways, but not cheaper, simpler and smaller ways. I have some Power Trends modules, older models that drop into 78xx slots. Cute. I wonder if they've expanded their line... James Arthur
From: langwadt on 15 Nov 2009 17:35 On 15 Nov., 23:08, John Larkin <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > On Sun, 15 Nov 2009 21:48:22 GMT, Jan Panteltje > > <pNaonStpealm...(a)yahoo.com> wrote: > >On a sunny day (Sun, 15 Nov 2009 13:09:30 -0800) it happened John Larkin > ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote in > ><abr0g5pgk26nsabqgu2jr9q6r1rmcrm...(a)4ax.com>: > > >>>> I *told* LTC to > >>>> do this, and, incredibly, they haven't got around to it. It's not as > >>>> if FPGAs are losing popularity. > > >Voltages and how many change all the time, better have separate switchers, > >Havin ga 3 in 1 would reduce the market by a factor 9 :-) > > The LTC switcher voltages are usually programmed with one or two > resistors per output. An SPI interface to a nonvolatile memory would > be even better. > > > > > > >>>> The Spartan 6 parts will run from two supplies (Vccint can run from > >>>> 3.3) but we want to use a DDR dram, at 1.8 volts, so we're back up to > >>>> three. > > >>>something like a ISL65426 and an ldo? > > >>>-Lasse > > >>The LTM4615 has all that inside, including the inductors and LDO. That > >>may be the most compact solution, for $24. > > >You make small series with high profits. > >No reason not to use 3 switchers. > > We're space constrained by the fixed size of a VME module. The current > project is a 16 channel differential-input digitizer with BIST and a > 32-bit interface (requiring two DIN connectors and lots of buffers to > the backplane.) It's very tight, and the more features we include the > more we can sell. Wasting 2 or 3 square inches on voltage regs is > silly. > > We commonly build products with 8 or 9 separate power rails, with the > power regulators over a third of the board area. This is getting > silly. SIPs would be useful, to use available height instead of > valuable board surface area. The thermals might be better, too. > > John traco has some 1A SIP modules , http://www.farnell.com/datasheets/328966.pdf they also have some 6A/10A sil modules -Lasse
From: Jan Panteltje on 15 Nov 2009 18:27 On a sunny day (Sun, 15 Nov 2009 14:08:59 -0800) it happened John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in <vbu0g5pb9ocob428c3h9h3jadld11rfml9(a)4ax.com>: >We commonly build products with 8 or 9 separate power rails, with the >power regulators over a third of the board area. This is getting >silly. SIPs would be useful, to use available height instead of >valuable board surface area. The thermals might be better, too. Can you not make small vertical boards with each a switcher? The disadvantage of vertical is that it is more sensitive to mechanical vibration causing bad contacts or broken solder joints.
From: Joel Koltner on 15 Nov 2009 19:58 <dagmargoodboat(a)yahoo.com> wrote in message news:af498889-885b-4f34-a82f-e44762b0da94(a)p8g2000yqb.googlegroups.com... > I have some Power Trends modules, older models that drop into 78xx > slots. Cute. I wonder if they've expanded their line... TI bought Power Trends (in 1999!) and, yes, they have expanded the line since then.
From: dagmargoodboat on 15 Nov 2009 20:14
On Nov 15, 7:58 pm, "Joel Koltner" <zapwireDASHgro...(a)yahoo.com> wrote: > <dagmargoodb...(a)yahoo.com> wrote in message > > news:af498889-885b-4f34-a82f-e44762b0da94(a)p8g2000yqb.googlegroups.com... > > > I have some Power Trends modules, older models that drop into 78xx > > slots. Cute. I wonder if they've expanded their line... > > TI bought Power Trends (in 1999!) and, yes, they have expanded the line since > then. Hmmm, no luck. I went to the TI pages to look for power supplies, but all they had were power management solutions. -- Cheers, James Arthur |