Dialog Designs New PMICs to Help Cars Be Smarter, Not Hotter
AI embedded processors are becoming a staple in next-gen vehicles. But this high level of processing also generates massive heat. Multiphase buck technology can mitigate the trade-off.
This week, Dialog Semiconductor announced a new family of automotive-facing power-management ICs (PMICs) they hope can mitigate some of the power-centric challenges that automotive designers face today. In this article, we’ll cover some of these challenges and how Dialog’s new PMICs may solve them.
Dialog Semiconductor's new family of PMICs are described as highly efficient, high current step-down DC-DC converters. Image used courtesy of Dialog Semiconductor
Power Challenges in Automotive Design
One of the major challenges in automotive design is power efficiency and thermal management.
As cars get smarter, their hardware consumes more power. Tesla’s HW 3.0, for example, consumes up to 72 W peak. When data centers face massive power consumption, they require specialized active cooling solutions. But in a car, temperatures are hot to start, so active cooling isn't a realistic option.
When power and heat are a bottleneck, designers tend to be particular about their power circuitry, seeking out PMICs that offer a small footprint, high efficiency, and fast response to transience. This combination is hard to achieve, however; SMPS converters aren’t efficient enough and tend to require non-trivial amounts of external circuitry, trading off power efficiency for much-needed area.
One Solution: Multiphase SMPS Converters
One solution to this power efficiency/space conundrum is a multiphase SMPS converter.
A multiphase SMPS converter is essentially a parallel set of converters, each with its own inductor and set of power MOSFETs—referred to as a “phase.” During standard operation, each individual phase is activated at equally spaced intervals of 360° / n throughout the entire switching period, with n being the total number of phases.
Multiphase buck converter example. Image used courtesy of Texas Instruments
Compared to single-phase SMPS converters, multiphase converters are a better choice for high-power applications thanks to a reduced input and output capacitance, better thermal performance and efficiency, and better transient responses. Multiphase converters offer these benefits because the total current can spread evenly across the phases.
This means that the regulator can utilize smaller components and experience lower power losses across its non-ideal inductors and FETs—both attractive value propositions for automotive applications.
Dialog Leverages Multiphase Buck Technology
To approach the power and heat challenges in automotive design, Dialog Semiconductor has released its new DA914X-A family of PMICs, which leverage multiphase buck technology.
The higher power family, the DA9141-A, offers some impressive specs, including up to 40 A of drive current with an output voltage range of 0.3–1.3 V. Further, the family integrates all power FETs and control logic onto the 4.5 mm x 7.0 mm 60-pin FC-BGA package. This helps lower system BOM because only the inductors and capacitors are external from the IC.
The family also includes the DA19142-A, a similar device with a two-phase buck architecture that offers a drive current up to 20 A.
System diagram of the DA9141-A. Image used courtesy of Dialog Semiconductor
The DA9141-A family leverages a four-phase buck architecture to achieve high power efficiency and a footprint of 170 mm2.
A few other features that stand out for complex automotive electronics include remote sensing, which opens doors for several PCB routing scenarios without compromising performance. The family also has a programmable soft-start feature to regulate inrush current and slope control the output voltage.
Further, the DA9141-A PMICs include dynamic voltage control (DVC), which allows designers to adjust the supply voltage depending on the load.
The Complexities of Powering Autonomous Vehicles
As design challenges in the automotive sphere mount, designers will rely on continued innovation in the semiconductor space.
These step-down DC-DC buck converters are said to alleviate some of the thermal design concerns that come with powering current-hungry SoCs in vehicles today. That said, Dialog Semiconductor has expressed optimism that these devices may be used for ML and vision in autonomous vehicles—specifically to run AI or graphics embedded processors.