Keeping Tabs on Current Events: Q&A with Magnetic Sensor Maker Crocus Technology



Mobile devices, the IoT, data centers and our cars and homes all have a stake in smarter, more sensitive sensors.

Zack Deiri, chief sales and marketing officer, Crocus Technology, spoke with EECatalog recently about the company’s rugged magnetic technology, and the role he sees it playing in doing away with more costly, bulkier, less power-efficient ways of monitoring current flow for data center Power Distribution Units (PDUs).

EECatalog: Please give our readers a general overview of Crocus Technology.

web_ZackDeiri_CrocusZack Deiri, Crocus Technology: We are moving in two directions. One is licensing our technology in the automotive sector. The average car has between 20 and 30 magnetic sensors in it. We decided [to focus] on licensing [agreements] with the big sensor manufacturers in the automotive sector and have them bring our technology to the automotive world.

Two, we are bringing out products in three areas: switches, current sensors and rotation and speed sensors for the industrial and consumer markets.

Our investments [are aimed at] making smarter and smarter sensors by eventually integrating memory and processing right into the sensor itself. Over the next two or three years we’ll be bringing integrated devices to market, with our Holy Grail being to go to a smart sensor, to develop a smart sensor by early 2017—that is where we are focusing our energy.

EECatalog: What characteristics must be present in a successful platform technology?

Zack Deiri, Crocus Technology: Significant differentiation in performance, cost, or both.  We believe our Magnetic Logic Unit (MLU), which is a disruptive CMOS-based rugged magnetic technology, does offer both. Performance-wise, it has higher sensitivity, better high frequency performance, and better high temperature operation compared to traditional approaches (Table 1). Cost-wise, it offers lower cost and a small form factor.

Table 1. Key: Total Magnetoresistance Change (TMR); Anisotropic Magnetoresistance (AMR); Giant Magnetoresistance (GMR); Magnetic Logic Unit (MLU)

Table 1. Key: Total Magnetoresistance Change (TMR); Anisotropic Magnetoresistance (AMR); Giant Magnetoresistance (GMR); Magnetic Logic Unit (MLU)

EECatalog: What will be crucial to allowing MLU technology to take hold, and what challenges are you finding as you usher this technology into the market?

Deiri, Crocus Technology: I was in China recently visiting with guys who build PDUs for data centers. They want to know how much current each rack in the data center is absorbing. If the amount of current goes up or down or becomes abnormal, they know something is about to fail and [this allows them to] change the rack or replace the server before it goes down, which saves money, time and effort.

They have been using these huge transformers to measure the current that goes through each cable that goes into one of the racks. I told them, “You can replace this whole transformer with a tiny device,” and they were very skeptical.

To address this challenge [of introducing a disruptive technology], we have created demo boards to address high-volume market segments as well as white papers and application notes to allow customers to migrate from older technology to our Tunnel Magnetoresistance (TMR) technology.

The amount of space saved, and how much less heat is generated plus cost savings is what is turning skeptics into customers.

EECatalog: What are some of the ways sensors can expand their role in the IoT?

Deiri, Crocus Technology: We believe smart sensor technology, where the sensing and the processing of information occurs at very low power, will help lower the amount of information processing burden on the CPU and help drive adoption for the IoT.

It’s been a challenge to figure out how to process all this information that you get from all these different devices [in the IoT]. One approach is to localize the processing of the information.

For example, a sensor in your fridge or in your stove isn’t constantly sending information for no reason. Some of the processing happens locally, and only information that is relevant is sent out. That alleviates a lot of burden on the system in terms of pipeline and the amount of information that needs to be processed. Smart sensors have a way to store information locally and process information locally, so not everything gets sent out; only relevant information is transmitted.

EECatalog: How is the shift to smarter sensors relevant to Crocus?

Deiri, Crocus Technology:
Because our magnetic stack or our MLU technology is applicable to sensors and is the same as our memory, our magnetic RAM, it uses the same stack. We can take any CMOS process, we can think of it as a processor, and then deposit the magnetic stack on top of it, which could integrate the sensor and the memory into a single stack. [This approach] makes it very, very inexpensive and very powerful, because now you have the sensor and the memory integrated together along with the CMOS  (the processor). [The amount of] space [needed] would be very small in terms of the thickness of the processor and also the size of the device. In addition, because our magnetic stack is very low power, you can have a very low power device.

Also, Magnetic RAM is one of the most secure RAMs, just by its architecture. Most of the devices used in the world are either Flash based or SRAM based. All of these devices are what we call charge trapping technology, which means they have electrons that move from side to side and people know how to break into these types of devices. Magnetic RAM has no moving electrons in it, and it is extremely difficult to break into.

EECatalog: You have a cross-licensing agreement with ARM.

Deiri, Crocus Technology: Yes. We get one of their cores to use in our product development and they get our embedded MRAM technology. ARM wants to explore the potential of our magnetic memory—magnetic MRAM—to utilize as an embedded memory. Magnetic RAM, in theory at least, could run at the same speed as SRAM, but it is nonvolatile—so it acts like Flash but runs at the speed of SRAM.

When you have this capability, you can replace SRAM, Flash, EEPROM—whatever technology you are using in embedded—with MRAM.

The other advantage to Crocus MRAM is the fact that it would only require two to three layers above CMOS. So if you think about putting Flash technology on top of your CMOS processor, you need a lot of layers, many, many layers. [But] for MRAM, it’s only two to three layers above CMOS, which makes it inexpensive to manufacture, and makes it very, very capable.

EECatalog:
How is Crocus taking advantage of opportunities to create synergy across the various applications and needs the company’s solutions are addressing?

Deiri, Crocus Technology:
Our major goal in all applications is to provide solutions that are smart, efficient, and beneficial to customers in many areas. Intelligent PDUs is one such application where customers get multiple benefits including lower cost, smaller form factor, and superior performance as compared to current solutions. For instance, these smart sensors could measure the amount of current driven into each server rack in a data center and when the amount of current usage creeps up, a warning could be triggered to service the server before it fails.

EECatalog
: Is the mobile market ready for the higher sensitivity that your company’s technology can bring to mobile applications?

Deiri, Crocus Technology: The mobile market could definitely take advantage of our sensors in two different ways. A switch, which is used for instance in most notebooks, allows the screen to shut off when the lid is closed. Most of these applications today are using mechanical reed switches or Hall effect sensors. Both of these solutions have issues.

The reed switch is a mechanical device made out of glass, which could fail over time. Hence, when you close your computer’s lid, the screen remains on and eventually kills your battery. The Hall effect sensor has low sensitivity and draws current constantly even when not in use, which also drains your battery.

Therefore, our MLU/TMR sensors have huge advantages against both of these technologies. For one, they are CMOS and can be easily installed and will operate over billions of cycles. Second, they don’t draw current when not in use; and third, due to their high sensitivity, the magnets installed in the lid can be downsized in both size and strength by orders of magnitude compared to what is currently being used. The magnet that you insert in the cover of the lid can be around 30x smaller versus what is being used today. You can make the screens much thinner, and you can have very, very low standby current, which is a win-win for these types of applications. This translates to cost-savings in both production and assembly.

So we are going after these applications very heavily with our integrated switch, which   we’ll start sampling at the end of this year, and we are going specifically after these types of applications in the mobile space.

EECatalog: There is a green technology tie-in here.

Deiri, Crocus Technology: Right. A lot of people want to know how much electricity they are using in their homes, and are using smart plugs.

One of the things smart plugs do is notice if the current you are drawing out of the socket remains very low. The smart plug waits a period of time, and if they notice you are not drawing as much current as would be needed to power a device—a few milliamps—they shut it off, which could add up to huge savings over a year or two.

So we are replacing these transformers and these smart plugs, which are big and bulky because there is a big transformer inside to detect this small current. Our device can do this detection [yet] is 1/100 the size, and significantly lower current because these transformers also have to remain powered, which means they heat up. Our device doesn’t do that. It’s a magnet. If you do not have anything to actuate it, it remains asleep. When it has a field (current) around it, it wakes up. [Using our device] would simplify the circuit and make it   smaller. Eventually the [smart] plug will be as small as the plug you use now for any of the applications at home.

EECatalog: So this technology is letting engineers re-imagine—

Deiri, Crocus Technology: More than re-imagine, implement. And they are shocked by how small it is. All the Electrical Engineers are trained in school that if you are going to measure a current you have to use a coil, and now you are saying, “okay, you get rid of the coil, you get rid of all that, all you have to do is run the cable, the wire itself, run it on top of our sensor and you can get very precise measurements of the current that is flowing through. That revolutionizes things and makes things much simpler and much smaller.

At present, smart meters also use big coils to measure current, so that’s one of the applications we’re targeting, and we’ll be releasing an application note on smart meters.

EECatalog:
Any additional comments before we wrap up?

Deiri, Crocus Technology:
We provide app notes and demo boards for every application you can think of to enable people to build their own applications with our MLU technology. It is really revolutionary and it allows them to do things differently, all the way from IoT to green plugs to electrical to electric vehicles to motor control—I think they are going to come up with very, very smart applications for this type of technology.