Last month, Dr. Venu Menon, VP of Analog Technology Development at Texas Instruments, gave a keynote speech at the ISQED conference in Silicon Valley titled “Applications Drive Analog Technology Development and Innovation.” During his keynote, Dr. Menon noted that analog IC unit growth is outpacing overall semiconductor unit growth, for three key reasons:
- By providing new solutions to old problems (power tools, appliances)
- Opening up and enabling new analog applications (solar, battery-driven bicycles, and other energy-efficient devices)
- By opening whole new markets that put electronics in places electronic systems have never been (building, bridge, and structure sensors; food-quality monitoring; portable medical instrumentation)
Analog plays a large role in many parts of the typical system block diagram. In fact, thanks to what Dr. Menon called “sensorization,” analog permeates the typical system design as shown in the block diagram he used during his keynote talk:
I interviewed Dr. Menon after his keynote speech. With analog ICs’ rapid unit growth relative to other semiconductors, with analog’s push deeper into existing markets, and with the entry into new markets as a backdrop, I wanted to hear Dr. Menon’s views on analog design’s role in low-power design, because there certainly is one. A big one.
In response to my question on the low-power aspects of analog ICs and system design, Dr. Menon chose to first focus on power conditioning. Power conversion and power management ICs are two large chunks of TI’s analog product portfolio, he noted. “Wired and wireless power ‘care-abouts’ are different,” said Menon. In the world of wired power, there’s certainly a concern about power efficiency but there’s a bigger concern about delivering consistent power in a world where the 220V or 240V power mains can fluctuate by 100V or even 200V. Delivering consistent power under those extreme conditions is the realm of power conditioners and power controllers.
In the world of unwired power—which includes laptops, portable medical equipment and instrumentation, and an exploding world of sensors—designers are looking for very long operational life from a battery charge. In some situations, you can never recharge the batteries (think strain and structural-integrity sensors embedded in bridges), yet you want years of operation from that sensor because they are difficult to replace. Except for the laptop computers, almost all of the systems designed for this battery-powered arena are based on microcontrollers, so designers are looking for low-power microcontrollers—and all such microcontrollers are now mixed-signal devices with substantial analog content.
Menon was quick to emphasize one such microcontroller, the Wolverine, just introduced by TI slightly more than one month ago. The headline of the Wolverine press release pretty much says it all: “TI’s new ‘Wolverine’ microcontroller platform slashes power by 50 percent versus any other microcontroller in the industry.”
Architecturally, the Wolverine is part of TI’s very successful MSP430 16-bit microcontroller family. Some of the Wolverine’s key low-power aspects include a 360 nA real-time-clock mode and less than 100 μA/MHz active power consumption. Also significant is the Worlverine’s on-chip, non-volatile memory storage. It’s based on FRAM (ferroelectric RAM) rather than Flash memory. If I am reading the press release correctly, TI says that FRAM consumes 250x less energy per bit than Flash or EEPROM memory commonly found in other microcontrollers.
Certainly one of the reasons for this huge energy advantage is that FRAM has fast enough write cycles to allow it to replace on-chip SRAM as well as Flash memory or EEPROM. The FRAM is a unified on-chip memory in the Wolverine implementation of the MPS430 microcontroller architecture, which not only offers energy advantages but also considerably cleans up the programming challenge of dealing with multiple types of on-chip memory. The press release also mentions “precision peripherals” including internal power management and a 12-bit A/D converter that runs on a mere 75μA. The need for precision in analog IC process technology was one of the main themes in Dr. Menon’s ISQED keynote.
Other big “care-abouts” in the battery-powered world, continued Menon, are battery-charging circuits and battery-management ICs that can efficiently convert battery power to multiple supply voltages. The ICs that perform these tasks are essential to the product’s overall power use. You need ultra-low-leakage IC process technology for such products. In addition, non-volatile memory such as the FRAM used in the Wolverine microcontroller is very useful here as well, concluded Menon.