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View Full Version : Nice Buck/Boost Converter chip for Propeller



Philldapill
03-22-2009, 01:31 PM
I was looking over some parts from TI, and came across THIS (http://focus.ti.com/lit/ds/symlink/tps63000.pdf). It's a buck/boost converter chip that boasts 96% efficiency, and can boost voltages as low as 1.9V up to 3.3V for the propeller or other devices. Also, it can output up to 1.2A. Pretty beefy IMO. Oh, and Quiescent current at 50uA. Seems great for low power applications.

I might order a few of these, and brew some PCB's up for them. If anyone wants one, let me know.

TreeLab
03-22-2009, 01:51 PM
THis is very nice, but note that the current limit drops to 800 mA when boosting the voltage. I did not see any spec on the cross-over between buck/boost modes. Is there any chance the power would drop enough to cause the prop to reset?

Cheers!
Paul Rowntree

Dr_Acula
03-22-2009, 02:36 PM
I got really excited about these last year and even got TI to send me some samples (for free, too!). When they arrived I couldn't find them. The entire chip is 3mm x 3mm. I'd have to go off coffee for a week to even attempt to try to solder them. Probably would need solder paste and a reflow oven. I wonder if there is a board out there with the chip already soldered on the board?

Post Edited (Dr_Acula (James Moxham)) : 3/22/2009 11:12:24 AM GMT

Cluso99
03-22-2009, 03:33 PM
Nice but too small for me to see :-(

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Ale
03-22-2009, 08:13 PM
I got some of those. They are tiny!. So I settled for a boost-only model with a larger package (I think a TSP61070).

mctrivia
03-22-2009, 11:06 PM
I can make a breakout board for these ic(or for any ic for that matter I build custom modules cheap and can even do bga)

if any want I will assemble some

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Need to make your prop design easier or secure? Get a PropMod (http://propmodule.com) has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.

Philldapill
03-22-2009, 11:34 PM
Ha! You may beat me to it, mctrivia.

As for the idea of power loss when the chip switches from buck to boost, or vise versa, the datasheet says it's automatic. I assume that with adequate capacitors, the transition wouldn't cause a problem since it happens so quickly(microseconds). I'll try and make a few breakout boards and see how they work.

Treelab, are you seriously complaining about 800mA??? 800mA coming out of a 3x3mm package? I was amazed at the current... :)

mctrivia
03-23-2009, 02:09 AM
well if you have ability to assemble small parts go for it. I can have it made and assembled in 1 week. with all needed supporting parts and pin compatible with analog regulators

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Need to make your prop design easier or secure? Get a PropMod (http://propmodule.com) has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.

TreeLab
03-23-2009, 10:44 AM
No, 800 mA should be enough for most folks (including me) and most apps (including mine). I was just drawing attention to the difference between the buck/boost modes. To be honest, I hadn't even considered the form factor.

Cheers!
Paul Rowntree

Dr_Acula
03-23-2009, 12:54 PM
mctrivia/philldapill, sounds an interesting offer. What would be the ballpark cost?

I'm interested in getting 3.3V and 5V from two batteries. Something that replaced a TO220 reg would be cool. There was a similar one I found that stepped up from one nicad. I can't find the product number right now. Dual cell would be fine though because it drops out at 1.8V so it would stop working when the first cell goes flat - which would prevent reverse polarity on the cell which is the #1 cause of premature failure of rechargeables.

Post Edited (Dr_Acula (James Moxham)) : 3/23/2009 5:00:52 AM GMT

mctrivia
03-23-2009, 01:50 PM
cost depends on quantity I make.

2 modules is my minimum and is 30 can + parts

100 modules is 12 + parts

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Need to make your prop design easier or secure? Get a PropMod (http://propmodule.com) has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.

mctrivia
03-23-2009, 05:36 PM
Ok finally got home and looked through datasheet and everything. To build modules pin compatible with analog regulators I can make in quantities of 10 for $30 CAN($24.27 US at current exchange) each + shipping($15 max world wide for regular air)

Quantity of 10 meaning in total I need to sell 10 not that you need to buy 10 yourself. So anyone interested? If I send out for PCB Tuesday I will be able to ship next Monday(March 30)

Will make both 3.3V,5V, and variable models

Modules are fully assembled and tested.*



*Variable model requires you soldering on two 0603 resisters for reference voltage.

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Need to make your prop design easier or secure? Get a PropMod (http://propmodule.com) has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.

Mike Huselton
03-23-2009, 07:30 PM
What is the part number?

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JMH

mctrivia
03-23-2009, 11:05 PM
TPS63000 to TPS63002.

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Need to make your prop design easier or secure? Get a PropMod (http://propmodule.com) has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.

mctrivia
03-24-2009, 03:21 AM
forgot to mention there will be 1 extra pin then analog regulators. enable pin will be on back but can be removed if you don't need to shut off.

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Need to make your prop design easier or secure? Get a PropMod (http://propmodule.com) has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.

Philldapill
03-24-2009, 06:55 AM
Ok, so here is a rough draft of what the final layout for my regulator would be. It's the same pinout as a standard 7805 regulator(Vin - GND - Vout). They would either be in a fixed 3.3V, or 5V package(just different chips).

EDIT: 2nd picture is the most recent. I had to change the inductor to a through-hole component.

Post Edited (Philldapill) : 3/24/2009 12:04:11 AM GMT

mctrivia
03-24-2009, 07:51 AM
just so you know the inductor can not be found in that package

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Need to make your prop design easier or secure? Get a PropMod (http://propmodule.com) has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.

Philldapill
03-24-2009, 07:53 AM
mctrivia, you're right. I've been trying to source that part. Luckily, I've found a 790mA TH package that would easily fit. I'm changing the uploaded image to show it.

Timothy D. Swieter
03-24-2009, 08:13 AM
I would recommend spacing your SMD packages out a little more. There are very close or nearly overlapping which could cause trouble during hand or automated assembly.

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Timothy D. Swieter, E.I.
www.brilldea.com (http://www.brilldea.com) - Prop Blade, LED Painter, RGB LEDs, 3.0" LCD Composite video display, eProto for SunSPOT
www.tdswieter.com (http://www.tdswieter.com)

mctrivia
03-24-2009, 09:06 AM
also interesting thing. the formulas show you need at least a 3.5uH inductor for full range though schematics show a 2.2uH


I just figured out I can produce this for $12US if I can make 25 of each. Though it would be a 2 week turn around not my normal 1 week.

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Need to make your prop design easier or secure? Get a PropMod (http://propmodule.com) has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.

mctrivia
03-24-2009, 11:02 AM
here is a diagram with all recomended parts. Enable pin is on back behind Vin(left). Dimensions are exactly the same as a 220 pack 7805

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Need to make your prop design easier or secure? Get a PropMod (http://propmodule.com) has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.

WBA Consulting
03-24-2009, 01:14 PM
I recently built a customer's product using a Linear Technologies LTC3440 for the same purpose. Provides a solid 600mA in both boost and buck modes and is in an easier to handle 10 pin MSOP package. Works great with a 3.7 volt Li-Ion battery pack for a 5 volt device.

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Andrew Williams
WBA Consulting
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