It used to be so simple. We could develop a board and just leave some space for the power. Then all you needed to do was take out a scientific calculator to find out how much current was required on the 5V and, usually, the +/-12V or +/-15V.
In larger systems, we would use a central 24V or 48V bus and supply this directly into the one DC-DC converter on the board. In smaller applications we would typically go for a small AC-DC power supply that could make the typical voltage rails in one supply. This started to change in the 90s when suddenly the IC market moved to lower supply voltages and cards needed 3.
3V as well. As the most power hungry boards emerged in the telecom market, it is not a huge surprise that Lucent Technologies was the first to develop a non isolated 20W system to fit most cards with the single-in-line package. It took until 2002 to finally reach a breakthrough when Tyco Power came up with the Lynx platform, a range of non isolated DC-DC converters containing three current ratings (5, 10 and 16A) and two input ranges (3-5.
5V and 10-14V). The output became user selectable (trim resistor) to make sure these products could also power next generation DSPs or FPGAs. Today this Lynx platform is the most common platform for non isolated point-of-load (POL).
Looking closer at these power hungry semiconductors, the trend here is miniaturisation or, better yet, more functionality on the same space. This is only physically possible when you reduce the input voltage. In the POL market we see the need for smaller products.
Analogue chip makers like Texas Instruments and Linear Technology came up with some silicon, but the king of tiny POLs must be Enpirion. It had to enhance the FET to be able to squeeze a complete buck converter into a tiny silicon package. To reduce the inductance, you need to crank up the switching frequency but also overcome the negative influence on the efficiency.
It is safe to say the POL market will depend on what happens in the semiconductor world. If tomorrow’s DSPs need 60A, we will see converters to do just that. But it is not only the volts and amps, it is also the number of different voltage rails on the card and per chip and it is management.
To overcome tracking and sequencing issues, it became important to time the voltages. The first simplified answer on the market was also the first big alliance: POLA (point of load alliance) where TI, together with Astec and Artesyn, decided on a range of converters that were true second sources of each other and you could easily manage your voltage rails. Soon after, Tyco followed with Lynx 2 and formed an open alliance with Synqor called DOSA (distributed power open standard alliance).
On the silicon side, you see companies like Summit focusing on management chips to program tracking and sequencing by using the on/off or enable of standard POLs, and also small VRMs and LDOs. But I am convinced the future here is digital so you can use software to manage power. I do not know when the market will be ready, but if you look at Power One’s Z series, you can see that the technology already exists.
Imagine a complex card with several higher current loads for some expensive DSPs and a couple of FPGAs.
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