Multipurpose Modular Light Bar Project: [04] PCBs in the making

RE: Multipurpose Modular Light Bar Project: [04] PCBs in the making

jc2048 — Sat, 19 Dec 2015 23:48:37 GMT

A few thoughts on the schematic.

1. This design is for 1.5A through the LEDs (300mV/0.2 ohms = 1.5A). Are your LEDs suitable for that?

2. Connection running through R5 looks messy and makes schematic harder to read

3. If single resistor for R8 is too expensive you can always put some resistors in parallel. Five 1 ohm resistors (1%), each 125mW [0805], in parallel, gives you 0.2 ohms (1%), 625 mW [which easily clears the 0.45W that you need].

4. C8 and R6 are intended for feeding in an external clock. (That's there for applications where there are several driver chips and you want them to be synchronised together.) If you don't want to do that you can leave them out and just use R5 to set the frequency. I

don't know what effect taking C8 to ground will have. Do the instructions with the demo board tell you to do that if it's not used (if so, it will be alright, but it's a waste to include two redundant parts)?

5. Where does R1 go to?

6. How are you going to control the brightness? At the moment you don't have anything connected to the PWM input (PDIM). Or are you going to adjust the current with IADJ? (is that what R1 is for?)

7. You have connections called GND to the gnd and pad of the chip, but not anywhere else.

8. R7 won't be 20.5 ohms. Did you intend 20.5k?

9. I can't say anything about the inductor because you don't say anything about it.

10. Are you going to be able to solder the thermal pad properly? I'm not sure I could.

Hope that helps. I only quickly scanned the datasheet, so verify things for yourself to make sure.

RE: Multipurpose Modular Light Bar Project: [04] PCBs in the making

DAB — Tue, 15 Dec 2015 19:39:35 GMT

Good post.

I look forward to seeing the completed circuit boards at work.

DAB

RE: Multipurpose Modular Light Bar Project: [04] PCBs in the making

ipv1 — Tue, 15 Dec 2015 16:55:36 GMT

Greetings Shabaz Sir,

I currently do not have a decent soldering station nor the fine tips and this is a good reason to add one to my wish list. Any tips and tricks on soldering small parts will be much appreciated since noobs like me do not know what the right questions to ask are. [View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-21357696-5bee-46cb-b9ac-ee65f9654001/contentimage_5F00_1.png:16:16]

Hi ABP,

I sent a CSV file of desired parts to the Bangalore office and they made the purchase for me. Unfortunately shipping is extra so I need to reimburse them... Need some time for that [View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-21357696-5bee-46cb-b9ac-ee65f9654001/contentimage_5F00_1.png:16:16]

RE: Multipurpose Modular Light Bar Project: [04] PCBs in the making

tonyboubady — Tue, 15 Dec 2015 15:06:05 GMT

Are you able to make purchase at in.e14 ? They have rejected my orders as I am an individual...even though I have used the voucher code... let me know what's the deal with them...:)

RE: Multipurpose Modular Light Bar Project: [04] PCBs in the making

shabaz — Tue, 15 Dec 2015 14:56:33 GMT

Hi Inderpreet!

Great post. Looking forward to seeing it in operation. Regarding the 0603, you may be pleasantly surprised, they are quite easy to hand-solder, but only provided these things are satisfied: 1: a small tip, 2: very thin solder, 3. tweezers that will hold it reliably without it flying in the air. Some flux perhaps but not normally needed if your parts and board are new.

You may have some of these already. If you need any tips/suggestions for these just let me know. Good luck with your board!