Cellular Stranglehold?

Do you ever feel like you are completely at the mercy of your cellular service provider?


Do you ever feel like you are completely at the mercy of your cellular service provider? Yeah, me too. Not only did I have to change providers when I relocated, I had to buy a new phone of course. Since my old phone and my new phone were both iPhones, I thought for sure I could use the same car charger….but no dice.

This fact has bothered me for quite some time because it made no sense to me and I had been blaming the service providers – both of which I have had frustrating experiences with.

During a conversation I had last week, I finally got the answer to why my old AT&T charger would not work with my new Verizon iPhone. Gene Matter, who started his engineering career at IBM, then spent more than two decade at Intel, now senior applications manager at DOCEA Power explained what had happened.

What basically happened is I got a new version of a phone that had a different modem than my old phone. He said when they put the modem electronics in there they also had a different AC to DC converter that went to the charging circuit to the battery. As a result of that, fundamentally, the USB connector and everything else is just fine. In other words, if I planned to charge this thing from a USB port on my computer it works just peachy but the old AT&T car charger adapter was probably not putting out as much current as the new phone needed. “It could be the output current because the new phone basically has a bigger battery. You’ll notice from the iPhone 3 to the iPhone 5, the circuit board shrunk and they increased the battery size. If there is a bigger battery in there, a bigger battery wants a lot more current instantaneously. It might be charging, but its charging down to a trickle,” he said.

I recall, based on teardown reports I read that Apple made some adjustment to the iPhone design when it added the Verizon version.

Matter confirmed this. “They had to because they used a different chipset. In the AT&T version, they used Infineon and then they swapped over to Qualcomm, I think, because Qualcomm’s the only company that has CDMA1 and the Verizon.”

This situation also highlights the fact that backward compatibility is a big deal especially for the aftermarket for replaceable batteries especially for notebooks and consumer electronics but not so much in smartphones. For more on battery technology, see, “Spoiled By Moore’s Law.”

He also pointed out the challenge that system designers have in dealing with power issues. “With battery capacity, the big thing that trumps things across the board is, ‘Get me a new technology that has really big charge capacity.’ When you look at a battery technology the spec sheet, are the voltages compatible? How much current can it generate? What is the battery capacity in terms of weight and volume. As a system engineer, I’m going to try to find in the sweet spot a technology that’s fairly new on the manufacturing curve so I’m ensured a fairly robust lifecycle and I can promise to the marketing guys that there are opportunities for cost reduction as this moves into volume production. I’m going to select that battery technology and I’m going to ensure that my parameters in my system –instantaneous current draw, weight targets if I’m in a handheld or weight sensitive market – and the availability of this technology, ideally from at least a reliable source. Now I’m dancing in a really tight corner all of a sudden based on my selection choices.”

So while I was blaming the cell service providers, I now understand the iPhone system architects were really just optimizing the system – and the least of their worries was my car charger. Given my respect for the system architects and designers, I’ll let them off the hook this time.


~Ann Steffora Mutschler

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