October 11, 2018

Power in small packages

One proxy for Moore's Law these days is how small a package an HD video decoder can fit into. 4K media streaming devices from Amazon, Google, and Roku are not much bigger than an older USB flash drive. Boggles the mind.

The Roku Express (maxes out at a mere 1080p) isn't quite that small, about half the size of a proverbial pack of playing cards. But I am equally wowed by the power supply it comes with. It's one of those now ubiquitous 5V/2A wall units commonly used as cell phone chargers.

The DC output must be electrically isolated, else iPhone and Android users would be electrocuting themselves right and left. This normally requires a bulky transformer. Instead, the 120 VAC is rectified and an oscillator chip kicks the current frequency from 60 Hz to 100 KHz.

At those frequencies, the flyback transformer can be smaller than a dime.

With a high-voltage MOSFET driving the primary coil, the result is a switching power supply that draws almost no power on standby (the Roku doesn't have a physical switch or even a shut-down sequence) and is the size of my thumb.


The image above is the reference design for a switching 5V/2A power supply with variable 85-265 VAC input from Texas Instruments. The circuit diagram is posted on the TI website.

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October 04, 2018

Toradora

There are times when a creative work so perfectly captures a genre or type that it henceforth defines its essence. As both a plot and character trope, nothing exemplifies tsundere better than Toradora and the character of Taiga Aisaka.

A tsundere is most often a girl who, as an initial response to a new situation or circumstance, reacts in a cold and hostile manner, often violently so (tsun-tsun). This behavior presents a sharp contrast with her moe outward appearance.

The guy who survives this onslaught of first (and second and third and twentieth) impressions will eventually discover her vulnerable and affectionate side (dere-dere).

The key word here is survive.

As with all well-worn types, tsundere can quickly wear out its welcome and fall into cliche and stereotype, especially when the guy functions as little more than a doormat. The quality of the conflict depends on the quality of the opposing forces. In Toradora they are formidable.

A "tiger" faces off against a "dragon."

In addition to the native Japanese terms, tigers and dragons can be referred to using "loan words" or English cognates. So tora (虎) is Japanese for "tiger." So is a taigaa. The dragon imported from European fantasy is a doragon. A Chinese dragon is a ryuu (竜 or 龍).

Toradora combines the two, meaning "tiger and dragon," which also refers to the two main characters, Taiga Aisaka and Ryuuji Takasu.

The actual kanji for Taiga's name (大河) mean "big river." As everybody likes to point out, it's not a common name for a girl. So given her personality and diminutive size, Taiga has been nicknamed "Palm-Top Tiger."

Imagine a Tasmanian Devil personified as a cute teenager (rather than the Looney Tunes cartoon). In fact, Taiga so dominates the narrative with her explosive antics that is is easy to overlook the fact that the three other main female characters are world-class tsundere as well.

Minori Kushieda is a tomboy and captain of the softball team. Sumire Kano, the student class president, hilariously governs like a Marine Corps drill instructor. Though nobody appears all that intimidated by her, and vice-president Yusaku Kitamura is always one step behind her to smooth the waters.

Ami Kawashima is a teen fashion model taking a hiatus while she deals with a
stalker. She soon learns to handle her problems the Taiga way.

The male-female ratio notwithstanding, it is not a harem series. As with Tomoya and Nagisa in Clannad (another harem-but-not-really series), the chemistry between the main characters is such that the only question is when and how they will end up together, not if.

Toradora begins with Taiga admiring Yusaku Kitamura from afar, and Ryuuji pining for Minori Kushieda. While too many complications spring from wrongheaded presumptions and poor communication, considering the introverted nature of Japanese society, it did not strain belief for me.

Actually, the first scene of Toradora has Ryuuji trying to dispel the wrongheaded assumptions most people make about him.

In this respect, it's not hard to see Toradora as a upside-down version of Clannad. At the beginning of Clannad, Tomoya and Satoshi have dedicated themselves to being the school's juvenile delinquents. And then one day Tomoya encounters the quiet and gentle Nagisa.

On the other hand, to his constant irritation, everybody outside his close circle of friends believes Ryuuji is a juvenile delinquent. His mother works in a hostess club. His father was a yakuza who (he's been told) got killed in a gang hit. People who don't know Ryuuji are scared to death of him.

Except that Ryuuji grew up being the only responsible person in the house. He'd rather shop for dinner than pick a fight. As in Clannad, he runs into a girl who is his psychological opposite. After much melodrama, they manage to grasp what the other needs and smooth out the rough parts.

Another similarity between the two series is that, although romances, they ultimately avoid idealizing teenage infatuation.

In the concluding dramatic arc, Toradora races toward a Romeo & Juliet conclusion (without anybody dying). But the lesson Taiga and Ryuuji arrive at independently is that when you and everyone you know has that many issues, you should deal with them first. Love will not conquer all.

Rest assured that a happy ending is in the offing, though you'll have to stick through the closing credits of the last episode for the delightful pay-off.

Toradora is a light novel series by Yuyuko Takemiya and has been adapted to manga and anime. The anime is available on Crunchyroll and Tubi.

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