电路设计软件如Protel(后演化为Altium Designer)、OrCAD、PADs、Allegro等是硬件工程师必备的工具,电路仿真软件对工程师的设计工作也非常重要。这些工具软件历经多年,可以说是都比较成型、成熟,如同测试、测量仪器,就剩下那么几个EDA的巨头在玩,虽然他们的注意力都在更赚钱的领域 - IC设计,PCB设计工具显得并不那么重要,当然除了Altium公司除外。

随着网络的普及以及网络概念如协同、社交等的火热,一批草根如沐了春雨一样的从大树底下悄悄成长,根植于网络这块肥沃的土壤,试图采用最新的技术和新的商业模式来颠覆这个由巨头把控的行业,我们暂且听听SnapEDA(专注于电路设计的CAD社区)的美女创始人Natasha在Electronic Design讲述的故事...

The Rise Of The Online Circuit-Design Collective

Natasha Baker, SnapEDA

Though still in the infancy stage, design and simulation tools that run entirely in the browser are pushing their way onto the EDA landscape. The ultimate goal is that they become essential players within the realm of professional design.

It has taken decades for industry leaders like Altium, Cadence, and Mentor Graphics to build out complex layout and simulation features. New startups say they want to compete with these companies, though, and that their tools could approach the same level of complexity within the next year.

Web-based software extends benefits like accessibility, collaboration, and transparency. Because it runs entirely in the browser, the software is accessible from anywhere, across platforms, and without requiring installation. The tools encourage an open community that shares designs and parts libraries, giving designers a starting point for their own custom applications. In fact, some tools track design revisions, allowing teams to check in on each other’s designs.

Upstart Startups

Canadian-based Upverter, launched in 2011, seems to be the most aggressive in terms of targeting the enterprise market. Its software, which focuses on collaboration and usability, was recently updated to include board-layout and simulation capabilities on top of its existing schematic capture offering.

According to the company, nearly all of its users build off of one of thousands of publicly available designs and libraries (Fig. 1). Its tools were born out of a frustration with overly complex design flows, which tend to impede collaboration. “There’s an old way of doing things and an old mindset and a lot of ‘I do it like this because I’ve been doing it like this for 20 years,’” says Zak Homuth, a co-founder of Upverter.



1. This timer circuit schematic is one example of a design in Upverter that allows multiple collaborators on the same design.

Another browser-based design tool dubbed Circuits.io (launched in October) was built upon a similar premise. Co-founder Benjamin Schrauwen, a professor in the electronics field at Belgium’s Ghent University, feels that existing tools have a steep, and unnecessarily long, learning curve. “We again and again see the tedious process when people are learning to design PCBs,” he says. “A lot of what we have to explain could be easily captured in just better tools.”

Both Upverter and Circuits.io offer an end-to-end design flow. In other words, designers can capture designs, create board layouts, generate Gerbers (standard file formats that provide detailed information on a printed-circuit board’s conductive layers), or order manufacturing within the tools.

Upverter maintains over 17,000 parts in its library as well as thousands of publicly available designs for reuse. It can support designs with hundreds of components, thousands of nets, and up to approximately 10 square inches in size, according to Homuth. Its layout tool supports an infinite number of layers.

Other features include design-rule checking and a wizard for IPC-compliant footprint generation. Upverter recently added the ability to incorporate copper pours and revamped its trace routing (Fig. 2). Currently in the works is support for BGA breakouts and differential pair routing. Homuth says that the company updates its design tool daily and reacts quickly to customer requests.



2. Upverter’s Web-based PCB editor has support for DRC and copper pours, and includes an IPC-compliant footprint wizard.

Circuits.io lists approximately 1600 parts, but it plans to significantly increase that number in the near future. Although support is available for infinite layers, users can only design two-layer boards at this point. The company recently added support for copper pours and improved routing capabilities, and hopes to soon offer support for higher-frequency boards (Fig. 3).



3. Circuit.io’s layout tool supports snap lines to align components, an adaptive grid, live ratsnest, ERC and DRC checking, live copper-pour calculations, and copper island removal.

Early adopters of Circuits.io fall into the student and hobbyist groups, but plans are to expand to professionals looking for a simple design tool. According to the company, its users are currently creating simple designs, such as interface boards, logic analyzers, and extension boards for their Raspberry Pi or Arduino boards.

Upverter, on the other hand, says that professionals have begun to come onboard. Most of them are involved in startups, and design projects generally fall into the consumer electronics and robotics realms. “Altium, OrCAD, and PADS are the guys who are in our sightlines now,” notes Homuth.

Open-Source Hardware

Both Upverter and Circuits.io point to GitHub as an inspiration for their design tools. GitHub is a Web-based software code hosting service and community with over three million users.

The service has popularized managing code publicly online. It allows members of the community to “fork” a code repository, enabling them to build off of their own working copy. As a result, they can more rapidly customize their own applications.

While Upverter is betting that this idea will catch on for professional electronics design, Circuits.io sees it as a way to involve more companies in custom electronic design. By modularizing standard design blocks and automating most of the design process, they hope to lure technical folks outside of electronics into designing custom circuits (Fig. 4).



4. Every Circuits.io design can be copied for reuse (“forked”) and watched. It also has a comments section for community interaction.

The companies envision designers encapsulating functionality and piecing together blocks, similar to how large open-source communities like GitHub influence the way many coders now write software. A power-supply expert, for example, might design modules that a less electronics-savvy designer could implement into his or her layout.

“The basic Circuits.io tool is really focused on simplicity because we have the idea that although the EDA market is big, it’s still a crowded market,” says Schrauwen. “So the best thing you can do is to make the market bigger—make a tool that allows more people to design electronics—not just individuals, but also companies.”

Schrauwen believes that in the long-run, companies currently using off-the-shelf microcontroller boards for prototyping will be able to build their own circuits with little electronics knowledge. The key is that they start from well-defined modules, which they can customize to fit their needs.


Upverter provides a Spice-based simulation engine that supports HSpice and Spectre models, according to Homuth. Support isn’t available for PSpice parameters, though.

Another startup called CircuitLab (launched in February 2012) started with a different approach by first focusing on simulation. It created a free Web-based simulation and capture tool that runs in the browser using JavaScript. Rather than build off of an existing Spice engine, CircuitLab established its own proprietary Spice-like simulation engine (Fig. 5). The company will reveal more details about the engine in the coming months.



5. CircuitLab provides easy in-browser schematic capture on Windows, Mac OS X, Linux, and iPad, without requiring installation.

The tool supports common analyses such as dc bias, dc sweep, and time- and frequency-domain analyses (Fig. 6). A Spice simulation model currently can’t be imported, but CircuitLab says that’s a top priority. End users, however, can configure the parameters of device models. For example, it’s possible to graphically define an op amp’s gain bandwidth product or slew rate, which will affect the frequency and time response of the simulation accordingly.



6. An op-amp regulated ac-dc power supply’s startup transient is plotted within CircuitLab’s mixed-mode simulation engine, running entirely within the Web browser.

University faculty and students within electrical engineering departments represent CircuitLab’s largest base of users. According to co-founder Mike Robbins, CircuitLab is being used at over 500 colleges and universities around the world. Every week, the site receives over 12,000 visitors who collectively run more than 80,000 simulations. Robbins says that CircuitLab, which is free, is replacing commonly used tools like PSpice, LTSpice, and NI Multisim in both undergraduate- and graduate-level analog and power design courses.

In addition to academia, professionals use CircuitLab to simulate small sections of a circuit. Designers can simply share a URL to communicate the design and simulation results to other engineers in their organizations.

Robbins says that while CircuitLab remains 100% focused on improving the accuracy and breadth of its simulation capabilities, the company does want to investigate incorporating board layout. “Our users clearly have an interest in doing both so we’re going to enable that in the future,” notes Robbins.

PartSim, a new product created by Aspen Labs (which also owns EEWeb) in partnership with DigiKey, is another Web-based standalone circuit simulator (Fig. 7). Open-source simulator ngspice, founded on Berkeley Spice3f5, powers the engine. Transient, dc bias, and ac analyses are supported, and a graphical waveform viewer displays results (Fig. 8).



7. PartSim includes a schematic capture environment, Spice simulation engine, and graphical waveform viewer.



8. In this example, PartSim simulated the transient response of an op amp.

The free tool doesn’t require users to login. To compete with other simulation tools, Aspen Labs plans to expand PartSim’s feature set and library of simulation models.

Barriers To Adoption

In light of the upsurge in Web-based tools, hurdles remain in regards to their adoption by large enterprises. Major concerns revolve around the technical capabilities of these tools, the longevity of the companies behind them, and security.

Aspen Labs co-founder Joe Wolin says that improvement in tool quality will be the main driver behind adoption. “It’s not about will they use them—it’s about getting the tools to be as good as desktop tools.”

Meanwhile, Circuit.io’s Schrauwen believes that the state-of-the-art in Web-based EDA tools still falls short of competing with major design tools, which will make adoption difficult. “Frankly speaking, if you look at what you can do with the current tools in the browser, it’s still limited,” he says. “In a year’s time, I think it will be unfeasible for any of the software-as-a-service EDA providers to come close to what Altium or Cadence are doing.”

The second concern amounts to assurances that a tool will be around for the long haul. Software-as-a-service companies move quickly, but they’re ripe for acquisitions or even going out of business. Thus, engineers need to feel relatively sure that they will be able to open their designs in, say, 10 years.

Concerns about security, on the other hand, are unfounded, according to the startups. That’s because many companies already use many cloud-based services to store their files. Nonetheless, Upverter, Circuits.io, and CircuitLab say that they can create private instances of their tools behind a firewall upon request.

“Security is a concern regardless of whether it's an in-house IT team or a cloud-hosted application,” says CircuitLab’s Robbins. “We look at our Web-based distribution model as just a better way of delivering software to a user’s computer. It's taken many years, but companies like Box, GitHub, and Google Apps have demonstrated that businesses and government agencies of all sizes are allowing some of their core operational data to live off-site.”

Web-based tools are as secure as credit-card numbers, health records, or other files already stored in cloud services like DropBox, says Upverter’s Homuth. He adds that they bring along other benefits like accessibility and backups.

The final challenge is demonstrating to companies that Web-based tools provide benefits over their existing desktop tools—and that will take time. “There’s a whole demographic of our potential user base that’s not going to get it—they’ll be scared of the cloud until they retire,” says Homuth. “The cloud’s going to win, but it’s going to take time.”

Another Option

The Scheme-It tool, unveiled last year by Aspen Labs and DigiKey, is an alternative method for simple schematic diagramming. It’s positioned as a high-level circuit brainstorming tool, or a “Visio of electronics.” Over the past 12 months, they doubled the size of the schematic-symbol database, redesigned the wiring, and added multi-page support. Adoption has grown considerably, especially with students, since professors are using it in their labs, says Randall Restle of DigiKey.

Restle indicated that the intent of the tool is to support DigiKey’s customers, and that the company doesn’t intend to enter into the CAD software market. “It’s not a tool-competitive against the circuit design tools or simulators. We’re simply trying to serve that underserved customer—the guy who likely doesn’t have much money for a CAD tool,” says Restle. “There is a lot of activity in cloud-based CAD tools, but the philosophy of DigiKey is that customers should have their choice.”


Upverter, Circuits.io, CircuitLab, PartSim and Scheme-It are all free to use. However, Upverter and Circuits.io make designs public in their communities, which may arouse concern among some designers.

For those concerned about disclosing their designs, both Upverter and Circuits.io offer a privacy option. Upverter charges $7 per month for individuals and $99 per month for teams; there’s no limit on number of designs. Circuits.io also offers this functionality upon request, and charges $4.99 per circuit.

Web-based design tools must make significant strides before catching up with industry leaders, but they continue to make headway. Over the next year, these companies all plan to build out the complexity of their layout features, and improve the accuracy and breadth of simulations. Though they’re just getting started, Web-based software allows them to respond to requests and bug reports quickly. Moreover, software is updated on a near-daily basis. Those capabilities make those significant strides come at a much quicker pace.

Web-based design tools must make significant strides before catching up with industry leaders, but they continue to make headway. Over the next year, these companies all plan to build out the complexity of their layout features, and improve the accuracy and breadth of simulations. Though they’re just getting started, Web-based software allows them to respond to requests and bug reports quickly. Moreover, software is updated on a near-daily basis. Those capabilities make those significant strides come at a much quicker pace.


Natasha Baker, founder of SnapEDA, a CAD community for circuit designers, previously worked at National Instruments and consulted for Analog Devices. Baker received a bachelor’s degree in electrical engineering from the University of Toronto, Canada. She can be reached at natasha@snapeda.com.