PMIC eases trade-off between power density and energy efficiency

Article By : Majeed Ahmad

New integrated voltage regulator enables DC/DC conversion without discrete components.

An integrated voltage regulator (IVR), a new category in power management chips, claims to have eased the years-long balancing act between power density and energy efficiency. Empower Semiconductor, co-founded in 2014 by three analog veterans, has created a 5×5 mm footprint that either eliminates or integrates the discrete components.

In a typical power management IC (PMIC) solution, many discrete components make it slow, expensive, and large. The company’s EP70xx family of PMICs, which it calls integrated voltage regulators, features triple output DC/DC power supply without external components (Figure 1).

Empower IVR compared to a leading PMIC designFigure 1 This comparison of two power devices shows a PMIC providing 11 A output and Empower’s integrated voltage regulator, which offers 10 A output. Source: Empower Semiconductor

The new power chip, based on Empower’s digitally-configurable hardware platform, simplifies the adoption of DC/DC converters by having multiple power supplies in a single IC. “Now power system designers don’t have to worry about filtering design and which inductor they are going to use,” said Steve Shultis, senior vice president of worldwide sales and marketing.

How did Empower eliminate all discrete components and make the chip configurable and programmable in a tiny form factor that can be placed anywhere in the system? Shultis said that while there are some capacitor technologies that enable the size miniaturization, especially in CMOS-based capacitors, the real innovation is the elimination of magnetics. “Inductor IP is the secret sauce,” he said.

According to Tim Phillips, Empower’s CEO, president, and founder, the inductor has always been a problem when you want things to be smaller. “So, by eliminating the magnetic components and multi-layer ceramic capacitors (MLCCs), the entire package becomes three to five times smaller than an inductor used in a typical power system.”

Phillips added that the industry has been solving the power density problem for the past five years, mostly by stacking of chips, which leads to trade-offs in cost and design simplicity. However, the industry has now hit a brick wall on switching frequency because it started impacting the efficiency, said Phillips. “It can’t get any denser without losing efficiency.”

Data centers are a low-hanging fruit

When it comes to the trade-off between switching speed and power efficiency, data centers are a case in point, which Shultis calls a low-hanging fruit for the company’s new power chip. Why? While everybody is focused on boosting the data rates, engineers don’t know what to do about power consumption. “Right now, data centers are trying to manage power through brute force of techniques such as thermal management and liquid cooling,” Shultis added.

Data centers have already maxed out in terms of how much heat they can dissipate. In other words, data centers are reaching extreme limits regarding power consumption, whether it’s network interface cards (NICs), servers, or fiber-optic transceivers. Servers, for instance, drive 40 percent of the power used in data centers.

So, while tiny devices with extremely high density, such as fiber optic transceivers, can’t get around power management, what makes matters worse is that power supplies are getting too big. As a result, they are getting too far from the point-of-load because of their size.

However, if system designers can get power management next to power-hungry processors, it will significantly improve energy efficiency. “The EP70xx chips are so small that they can be integrated right next to the load, providing designers with the ultimate density while also eliminating distribution losses,” Phillips said.

Then there is the chip’s ability to adjust the voltage on a processor on the fly; it can scale voltage from 0.5 to 1V instantaneously in 20 ns. Today, it’s typically done in 30 μs (Figure 2). That equates to energy savings on the processor side while the chip eliminates the transition time, which is a lossy event.

graph showing Empower IVR dynamic voltage scalingFigure 2 The ultrafast dynamic voltage scaling featured in the new chip enables the processor to change power states in nano-seconds. Source: Empower Semiconductor

Co-packaging with SoCs

While presenting data centers as a major testimony, the Empower executives emphasize that smaller footprint, power density, and dynamic voltage scaling features of the EP70xx chips also apply to AI, 5G, and mobile handset designs. DC/DC conversion is now in every single market, and EP70xx chips simplify it for designers.

Designers can simply place the chip on the PCB with no discrete components, select the settings using a graphical user interface (GUI), and load it via the I2C/I3C port. They don’t have to worry about input and output filter design, feedback resistors, and loop compensations.

Shultis said that there is a lot of interest in integrating the die into system-on-chips (SoCs) because it’s tiny and can go on the underside of the processor substrate. “It’s so thin that it can even be integrated on the bottom side of the package,” he said.

The EP70xx family of integrated voltage regulators comprises nine devices available in a variety of current configurations. Samples and demo boards are available while the full production is planned for the year-end.

Majeed Ahmad is Executive Editor at EDN, and has covered the electronics design industry for more than two decades.

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