Today’s teardown target is a DLO Power Bug model MH-01DU. This was a relatively expensive portable charger, that lasted a few years before getting into Kuzyatech lab. The complaint was that it made arching sounds, smelled hot and was not charging. Continue reading
I’ve just returned from Boston, where I poked my nose into Design East/Embedded Systems Conference. This was a very brief stop, limited to expo floor and panel discussions
This week’s part is a neat little chip from Texas Instruments. TPS2511 USB Dedicated Charging Port Controller and Current Limiting Power Switch. What this chip is designed to do is handle a bunch of newly developed USB charger handshaking protocols. As many familiar with Adafruit’s Mintyboost and other similar USB chargers for portable devices are aware by now, is that not all devices will charge if you simply give them 5V on a USB connector. Many will expect a particular level on the data lines, like certain i-devices, as documented by LadyAda. And yet others will want data lines to be shorted together to recognize the charger. This chip was designed to handle that automatically and hopefully provide a way to support future devices. Another nice feature is cable drop compensation. With high charging currents, the drop across that 6ft USB cable is no longer negligible. So what this chip does is add a bit of bias current to the feedback pin of a power supply feeding it. By doing that it is raising the output voltage by a predetermined amount to compensate for the drop. This feature activates when a load current exceeds a preset threshold.
TPS2511 typical connection diagram
Very nifty chip- expect a writeup for a project using it soon. But first we must get the boards back from the fab and see if anything smokes!
I’ve been tweaking my Sharp LCD breakout board to make it suitable to more users. The latest iteration is off to the board house, but here is a quick preview:
Sharp LCD breakout Rev A2
Yet another dead monitor made its way into the Kuzyatech lab. A 2007 vintage Viewsonic VA1930WM monitor that stopped turning on.The symptoms were classic- power on light cycles on and off, but the screen stays dark,while a faint repeating squeal can be heard from the unit. Sounds very much like that Samsung LN32A330 I fixed recently. Time to take it apart! Continue reading
A neat little sample kit has arrived: it’s a Linear Tech TimerBlox set.
What have we got here?
I have a few of the LCD breakout boards available for sale.
Schematic diagram is here .
Note: the header is included but not soldered, to make life easier in case you need to run wires to the board instead. Sharp LCD is not included. You can get the 5V version (LS013B4DN02) from Mouser. Part number is 852-LS013B4DN02. The boards were tested with Arduino Uno driving the LCD directly with 5V IO. That seems to be fine for the display according to the Sharp Datasheet.
First solder the header or wires as needed, then attach the display using a small piece of double sided tape and connect the flex. See my previous post for pictures on how a fully assembled board should look like, and this post for testing details
Connections for Arduino :
| Breakout pin | Arduino pin | Breakout Pin | Arduino Pin |
| 1 SCLK | 13 | 6 EXTMODE | 4 |
| 2 SI | 11 | 7 GND | GND |
| 3 SCS | 12 | 8 VCC | 5V |
| 4 EXTCOMIN | 3 | ||
| 5 DISP | 2 |
Shipping is via USPS First Class Mail. Items in stock usually ship the next business day ARO. Allow a week or so for delivery in the US
Sure, there is not much to test there- two connectors and a few caps. But the idea was to make the breakout so I can play with the display and see what I can design it in. For a while I stared at the datasheet, figuring out what it needs to be driven, then on a whim went to Google for an existing driver library for it. A library by craftycoder came up. It is based on Adafruit’s Arduino GFX library and includes an example that was more than enough to test the display. So I dug out my Arduino Uno and set things up:
Breadboard, Arduino Uno, uCurrent from EEVblog and a DMM.
This week’s find is a NSI450xx/NSI500xx family of parts from On Semiconductor. It’s a two terminal constant current regulator (CCR) offered in SOD-123,SOT-223 , SMB, SMC and all the way to DPAK cases. The device can handle 45V surges and regulates current to 15-350 mA depending on the individual part number. This makes it very convenient to insert into LED strings and have them stay in regulation and constant brightness with variable input voltage. Continue reading
My boards from OSH arrived a while back, so here are some pictures. The next step is getting the code running to test the display, though I may try feeding it some serial goodness from Bus Pirate as a test. So far it appears that the first test run of DipTrace tools and OSH Park service went pretty well!
Bare boards from OSH Park, in their requisite color! Both sides look pretty good.