Energy Density Roundup: New Belongings in a Energy Engineer’s Toolbox

Whereas it is at all times good to cut back the scale of any digital gear, there are particular size-constrained purposes that make board actual property a vital consideration. For instance, in fitness-related wearables and hearables (wi-fi earbuds), area is at a premium. In such purposes, the miniaturization of energy options is of paramount significance and might largely have an effect on the person expertise.

One other software space by which the scale of the facility answer is essential is the realm of IT and networking. With data-intensive purposes equivalent to cloud computing, synthetic intelligence, 5G, and high-speed networking, huge computational energy is a should.

In these circumstances, the designer has to miniaturize the facility provide as a lot as attainable to unencumber area for the computing horsepower. These examples are solely among the software areas the place growing energy density can considerably enhance current programs and even allow new markets.

The next determine reveals how the scale of 6-A to 10-An influence modules has shrunk over years.


Decreasing size of 6-A to 10-A power modules

Reducing dimension of 6-A to 10-An influence modules. Picture courtesy of Texas Devices


Decreasing the Dimension of Passive Parts

One of many keys to shrinking the scale of an influence module is reducing down the scale of passive parts, equivalent to inductors, which might be used for power conversion. This may be achieved by growing the switching frequency of a converter.

A switching converter makes use of passive parts to retailer and launch power in each switching cycle. As we improve the switching frequency, a smaller quantity of power must be processed in every cycle and thus, we will make use of smaller passive parts.

Nonetheless, with a better switching frequency, some loss parts known as switching losses improve. This may be intuitively understood by noting that with a better switching frequency, the parasitic capacitances of the circuit must be charged and discharged at a better charge. And, therefore, extra energy can be consumed.

One other switching loss element that will increase with frequency is expounded to the reverse-recovery phenomenon mentioned in a earlier article. To scale back the switching losses, we have to enhance the semiconductor expertise to have larger efficiency switches.

This may be achieved by both bettering the present applied sciences or engaged on extra trendy energy course of applied sciences equivalent to GaN gadgets.


Thermal Efficiency of the Package deal Is Essential

As mentioned above, a better switching frequency permits us to make use of smaller passive parts and enhance energy density. Nonetheless, this enchancment comes at the price of elevated switching losses and consequently, an increase within the generated warmth. Subsequently, we’ll have a smaller module that generates a comparatively bigger quantity of warmth.

It seems that it is tougher to get the warmth out of a smaller module. That is illustrated by the next determine that provides the package deal RΘJA (junction-to-ambient thermal resistance) versus the die space. 


RΘJA vs. die area

RΘJA vs. die space. Picture courtesy of Texas Devices


The above determine means that because the package deal dimension, die dimension, and general energy density improve, the thermal resistance goes up and modern packaging options are required to effectively switch the generated warmth to the encircling setting. The higher the package deal is at getting the warmth out, the extra energy losses we will afford with out experiencing unreasonable temperature rises.

Now that we’re extra aware of the challenges of bettering the facility density, let’s check out three recently-announced merchandise that purpose to supply a better energy density.


Maxim Built-in’s SIMO PMIC

The MAX77655 is a single-inductor multiple-output (SIMO) energy administration IC (PMIC) that gives 4 regulated outputs with a programmable output voltage within the vary of zero.5 V to four V. The corporate claims that the brand new gadget allows 85 % larger energy density and might present as much as 700 mA whole present from 17 mm2 PCB area.

However how can a SIMO enhance the facility density? A SIMO makes an attempt to shrink the scale of the facility module by sharing a single inductor between totally different switching regulators as depicted beneath. 


Block diagram of a SIMO architecture

Block diagram of a SIMO structure. Picture courtesy of Maxim Built-in


That is in distinction to the standard design the place every switching regulator wants a separate inductor. 

The MAX77655 targets purposes, equivalent to wearables, web of issues (IoT) sensor nodes, and well being screens, the place the designer must miniaturize the facility answer to unencumber area for the computing, reminiscence, and sensor sources.

The brand new gadget allows prolonged battery life by offering an effectivity of 90 % throughout reasonable to heavy load circumstances and a quiescent present of 6.9μA throughout mild load circumstances.


ABB’s DC-DC Converters

Whereas the MAX77655 is designed for low-power wearables, ABB’s DJT090 is a 90-A DC-DC converter that goals at high-current purposes equivalent to high-speed switches and routers, synthetic intelligence processors, and high-current FPGA-based processors.

The DJT090 presents a excessive energy density of 178-A/in2. Putting as much as Eight items in parallel allows a most output present of 720 A. A large enter voltage vary of seven V to 14.four V is supported and the programmable output is a exactly regulated voltage within the vary of zero.5 V to 2 V.


Silicon Labs’ Remoted Gate Drivers

Silicon Labs has additionally expressed a aim for energy density with its recently-announced remoted gate drivers, the Si823Hx/825xx. These gadgets are designed to present quicker and safer switching with low latency (a most propagation delay of 30 ns) and excessive noise immunity.

The brand new gate drivers goal energy provides for information facilities, micro inverters for solar energy, traction inverters for the automotive market, and industrial energy provides.

The Si823Hx/Si825xx are provided in a number of totally different package deal choices to satisfy the area necessities of right now’s compact energy modules. These compact drivers can be found in an Eight-pin package deal versus comparable 16-pin package deal alternate options. This reduces the system dimension and permits us to put the driving force near the facility transistor. 

Moreover, the brand new gate drivers present symmetric four A sink/supply capabilities. In comparison with the earlier era drivers, the supply present is nearly doubled, which helps to cut back switching losses.


Packing a Punch in a Small Package deal

Energy electronics could also be some of the essential areas to concentrate on energy density and system dimension. As Moore’s legislation nears its finish, it is seemingly we’ll proceed to see releases from big-name producers that emphasize package deal dimension and the facility that may match therein. 

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