triple switcher
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From: dagmargoodboat on 15 Nov 2009 20:33 On Nov 15, 6:27 pm, Jan Panteltje <pNaonStpealm...(a)yahoo.com> wrote: > On a sunny day (Sun, 15 Nov 2009 14:08:59 -0800) it happened John Larkin > <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote in > <vbu0g5pb9ocob428c3h9h3jadld11rf...(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. Joel prodded me to scout TI nee PowerTrends. They have a bunch of single-output 5-SIP modules that take about the real estate of a TO-220. PTR08060 -- 4.5-14Vin, 0.6 <= Vout <= 5.5V, Iout <=6A, $6 @ 1k (5- SIP) http://focus.ti.com/docs/prod/folders/print/ptr08060w.html PTH08080 -- 4.5-18Vin, 0.9 <= Vout <= 5.5V, 2.25A, $4.30 @ 1k (6-DIP pkg) http://focus.ti.com/docs/prod/folders/print/pth08080w.html Stocking one of those (or brethren) could cover a lot. Homepage @ "TI Home > Power Management > Plug-in Power Modules > Non-Isolated POL" (the URL's too long to post) -- Cheers, James Arthur
From: John Larkin on 15 Nov 2009 20:41 On Sun, 15 Nov 2009 17:33:36 -0800 (PST), dagmargoodboat(a)yahoo.com wrote: >On Nov 15, 6:27�pm, Jan Panteltje <pNaonStpealm...(a)yahoo.com> wrote: >> On a sunny day (Sun, 15 Nov 2009 14:08:59 -0800) it happened John Larkin >> <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote in >> <vbu0g5pb9ocob428c3h9h3jadld11rf...(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. > >Joel prodded me to scout TI nee PowerTrends. They have a bunch of >single-output 5-SIP modules that take about the real estate of a >TO-220. > >PTR08060 -- 4.5-14Vin, 0.6 <= Vout <= 5.5V, Iout <=6A, $6 @ 1k (5- >SIP) > http://focus.ti.com/docs/prod/folders/print/ptr08060w.html > >PTH08080 -- 4.5-18Vin, 0.9 <= Vout <= 5.5V, 2.25A, $4.30 @ 1k (6-DIP >pkg) > http://focus.ti.com/docs/prod/folders/print/pth08080w.html > >Stocking one of those (or brethren) could cover a lot. > >Homepage @ "TI Home > Power Management > Plug-in Power Modules >> Non-Isolated POL" >(the URL's too long to post) We looked at the TI stuff a while back. The external cap requirement is bad, as is the height. They run at 300 KHz! John
From: dagmargoodboat on 15 Nov 2009 20:49 On Nov 15, 8:41 pm, John Larkin <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > On Sun, 15 Nov 2009 17:33:36 -0800 (PST), dagmargoodb...(a)yahoo.com > wrote: > > > > >On Nov 15, 6:27 pm, Jan Panteltje <pNaonStpealm...(a)yahoo.com> wrote: > >> On a sunny day (Sun, 15 Nov 2009 14:08:59 -0800) it happened John Larkin > >> <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote in > >> <vbu0g5pb9ocob428c3h9h3jadld11rf...(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. > > >Joel prodded me to scout TI nee PowerTrends. They have a bunch of > >single-output 5-SIP modules that take about the real estate of a > >TO-220. > > >PTR08060 -- 4.5-14Vin, 0.6 <= Vout <= 5.5V, Iout <=6A, $6 @ 1k (5- > >SIP) > > http://focus.ti.com/docs/prod/folders/print/ptr08060w.html > > >PTH08080 -- 4.5-18Vin, 0.9 <= Vout <= 5.5V, 2.25A, $4.30 @ 1k (6-DIP > >pkg) > > http://focus.ti.com/docs/prod/folders/print/pth08080w.html > > >Stocking one of those (or brethren) could cover a lot. > > >Homepage @ "TI Home > Power Management > Plug-in Power Modules > >> Non-Isolated POL" > >(the URL's too long to post) > > We looked at the TI stuff a while back. The external cap requirement > is bad, as is the height. They run at 300 KHz! > > John That last one's 15x13x9mm, no output cap needed. The 1st one needs 100uF. James
From: MooseFET on 15 Nov 2009 21:43 On Nov 15, 10:41 am, 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. > > > > >I haven't been able to find a way to do it with either a PIC or a 555 > >but I'll keep thinking about it. > > To keep the inductor and cap sizes down, you've got to switch at a MHz > or two. Yes so you need a really fast PIC or 555 The ADC on the PIC isn't fast enough to do cycle by cycle voltage checking so you would have to close the servo loop at way less than Nyquist. Unfortunately this would also make the filter capacitors big.
From: dagmargoodboat on 16 Nov 2009 00:43
On Nov 15, 9:43 pm, MooseFET <kensm...(a)rahul.net> wrote: > On Nov 15, 10:41 am, John Larkin wrote: > > MooseFET wrote: > > 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. > > > >I haven't been able to find a way to do it with either a PIC or a 555 > > >but I'll keep thinking about it. > > > To keep the inductor and cap sizes down, you've got to switch at a MHz > > or two. > > Yes so you need a really fast PIC or 555 > > The ADC on the PIC isn't fast enough to do cycle by cycle voltage > checking so you would have to close the servo loop at way less than > Nyquist. Unfortunately this would also make the filter capacitors > big. I think you actually could do it with an AVR--their PWMs have ~40nS resolution. -- Cheers, James Arthur |