Dialog Semiconductor: plans for GaN
Dialog's delivery of GaN power ICs signals mainstream market adoption is close, reports Compound Semiconductor.
Industry developments including Dialog's recent market entry indicate the GaN power market is gaining more momentum.
Just a few weeks ago, UK-based Dialog Semiconductor revealed plans to sample GaN power ICs in a fast charging power adapter by the end of this financial year.
Following two years of collaboration with Taiwan Semiconductor Manufacturing Corporation, the power management IC supplier has developed a 650V GaN power IC plus controller combination, that is said to halve the size and power losses of silicon power management ICs.
"Until recently, GaN had been largely limited to small specialty fabs from vendors in Japan as well as research institutions," says Mark Tyndall, Senior Vice President of Corporate Development and Strategy at Dialog. "In contrast, Dialog targets high volume consumer applications, so it's never been our intention to prove GaN for, say, niche military applications."
"But when TSMC started to offer GaN as a standard process on six inch wafers, we saw that as a signal that this was the right time to enter this market as well as solve the emerging problems of size in the power adapter market," he adds.
Dialog's end-result is the so-called SmartGaN DA8801; a monolithic IC that integrates enhanced-mode GaN-on-silicon HEMTs with analogue drivers and logic blocks in a 650V half-bridge design for 25W to 65W adapters
By combining this IC with its 'Rapid Charge' power conversion controllers, Dialog can produce efficient, small, high power density adapters that look set to topple traditional silicon FET-based designs from pole position in the world of power adapters
"We're not trying to replace a silicon FET, with a pure GaN transistor; how could a six inch [GaN-on-silicon] wafer process compete with the [CMOS] manufacturer producing millions and millions of wafers?" points out Tyndall. " But we have optimised our solution around this GaN, half-bridge IC or active clamp architecture which allows us to provide a GaN-based system at the same cost, or even lower, that the traditional silicon FET system."
"We've reduced the overall bill of materials in our systems and we're getting a lot of excitement as we now have a small 45W adapter in a 25W adapter housing," he adds.
Crucially, this reduction in size paves the way to the universal power adapter that the mobile communications industry craves for its smartphones, notebooks, tablets and more. And according to Tyndall, Dialog customers are more than ready for GaN.
While he reckons initial concerns centred on device reliability, times have changed and industry has moved on. "We're really are beyond these issues now," he asserts.
Indeed, as Richard Eden, senior analyst at IHS Markit, highlights, Dialog is one of many moving towards GaN. "It's a safe bet that all silicon semiconductor suppliers are developing a strategy for GaN," he points out.
"During the last five years, start-ups such as Efficient Power Conversion, Transphorm and GaN Systems have successfully developed GaN products for the commercial market," he adds. "And more recently, larger silicon semiconductor companies such as Infineon Technologies, Texas Instruments and Panasonic have announced GaN developments."
For example, in March last year, Texas Instruments launched a 80V GaN FET power-stage comprising a high frequency driver and two GaN FETs in a half bridge configuration.
For Eden, these developments and Dialog's latest announcement are clear signals that GaN is now joining mainstream markets and is no longer considered to be a 'clever research lab experiment'. "And with foundry companies like TSMC now offering a GaN-on-silicon transistor process technology to clients, perhaps we will see more suppliers offering similar products using their own driver IC [technology]," he says.
State-of-play
Right now, Dialog is testing its GaN-based power IC with Beta customers and is set to sample during Q4, this financial year. The company's next move will be to ramp up production to volume levels, which Tyndall believes will take place by the middle of next year.
"We're strong in the fast-charging, mobile, power adapter market with around a 70% share and we're also entrenched with the top ten vendors in the China smartphone market," he says.
The Development and Strategy President doesn't foresee any supply chain issues - manufacturing uses standard CMOS equipment - but highlights: "We do need to be careful with back-end packaging and have chosen experienced vendors here."
"We also intend to use high volume, standard, device testers which fits with our desire to manufacture hundreds of millions of units without using niche manufacturing processes, equipment or fabs," he adds.
Then, with wireless device markets addressed, the company intends to turn to PC markets with a 100W power adapter, and eventually target server markets.
Looking beyond high volume consumer markets, Dialog isn't chasing industrial applications such as PV inverters, turbines and electric vehicles, although according to Tyndall, the company would 'never say never'.
However, the company has settled on GaN-on-silicon as its future technology of choice, over SiC, which Tyndall puts down to lower costs, better monolithic integration and higher volume production.
"We are looking to drive production volumes now," he concludes. "There is a chicken and egg element here as we need to drive volumes to drive the next level of fab investment that will bring us to a higher wafer size. But I would hope to move to eight inch wafers in the next two to three years."
