New Digitally Enhanced Power Analog Controllers

Microchip Technology recently announced its latest Digitally Enhanced Power Analog (DEPA) controllers—the MCP19118 and MCP19119—which offer analog PWM control for DC-DC synchronous buck converters up to 40 V with the configurability of a digital microcontroller. MicrochipMCP19118

Interestingly, the devices bring together 40-V operation and PMBus communication interfaces for power-conversion circuit development with an analog control loop that is programmable in the integrated 8-bit PIC core’s firmware.  According to Microchip in a product release, “this integration and flexibility is ideal for power-conversion applications, such as battery-charging, LED-driving, USB Power Delivery, point-of-load and automotive power supplies.”

As expected, Microchip’s MPLAB X, PICkit 3, PICkit serial analyzer, and MPLAB XC8s support the MCP19118/9 DEPA controllers. The MCP19118 and MCP19119 are now available with prices starting at $2.92 each in 5,000-unit quantities.


One Professor and Two Orderly Labs

Professor Wolfgang Matthes has taught microcontroller design, computer architecture, and electronics (both digital and analog) at the University of Applied Sciences in Dortmund, Germany, since 1992. He has developed peripheral subsystems for mainframe computers and conducted research related to special-purpose and universal computer architectures for the past 25 years.

When asked to share a description and images of his workspace with Circuit Cellar, he stressed that there are two labs to consider: the one at the University of Applied Sciences and Arts and the other in his home basement.

Here is what he had to say about the two labs and their equipment:

In both labs, rather conventional equipment is used. My regular duties are essentially concerned  with basic student education and hands-on training. Obviously, one does not need top-notch equipment for such comparatively humble purposes.

Student workplaces in the Dortmund lab are equipped for basic training in analog electronics.

Student workplaces in the Dortmund lab are equipped for basic training in analog electronics.

In adjacent rooms at the Dortmund lab, students pursue their own projects, working with soldering irons, screwdrivers, drills,  and other tools. Hence, these rooms are  occasionally called the blacksmith’s shop. Here two such workplaces are shown.

In adjacent rooms at the Dortmund lab, students pursue their own projects, working with soldering irons, screwdrivers, drills, and other tools. Hence, these rooms are occasionally called “the blacksmith’s shop.” Two such workstations are shown.

Oscilloscopes, function generators, multimeters, and power supplies are of an intermediate price range. I am fond of analog scopes, because they don’t lie. I wonder why neither well-established suppliers nor entrepreneurs see a business opportunity in offering quality analog scopes, something that could be likened to Rolex watches or Leica analog cameras.

The orderly lab at home is shown here.

The orderly lab in Matthes’s home is shown here.

Matthes prefers to build his  projects so that they are mechanically sturdy. So his lab is equipped appropriately.

Matthes prefers to build mechanically sturdy projects. So his lab is appropriately equipped.

Matthes, whose research interests include advanced computer architecture and embedded systems design, pursues a variety of projects in his workspace. He describes some of what goes on in his lab:

The projects comprise microcontroller hardware and software, analog and digital circuitry, and personal computers.

Personal computer projects are concerned with embedded systems, hardware add-ons, interfaces, and equipment for troubleshooting. For writing software, I prefer PowerBASIC. Those compilers generate executables, which run efficiently and show a small footprint. Besides, they allow for directly accessing the Windows API and switching to Assembler coding, if necessary.

Microcontroller software is done in Assembler and, if required, in C or BASIC (BASCOM). As the programming language of the toughest of the tough, Assembler comes second after wire [i.e., the soldering iron].

My research interests are directed at computer architecture, instruction sets, hardware, and interfaces between hardware and software. To pursue appropriate projects, programming at the machine level is mandatory. In student education, introductory courses begin with the basics of computer architecture and machine-level programming. However, Assembler programming is only taught at a level that is deemed necessary to understand the inner workings of the machine and to write small time-critical routines. The more sophisticated application programming is usually done in C.

Real work is shown here at the digital analog computer—bring-up and debugging of the master controller board. Each of the six microcontrollers is connected to a general-purpose human-interface module.

A digital analog computer in Matthes’s home lab works on master controller board bring-up and debugging. Each of the six microcontrollers is connected to a general-purpose human-interface module.

Additional photos of Matthes’s workspace and his embedded electronics and micrcontroller projects are available at his new website.




New 40-nm Microcontrollers for Motor Control

Renesas Electronics Corp. recently announced the RH850/C1x series of 32-bit microcontrollers (MCUs), which it said are designed for motor control in hybrid electric vehicles (HEVs) and electric vehicles (EVs). Based on Renesas’s 40-nm process, the RH850/C1x series features the RH850/C1H and RH850/C1M MCUs, which enable embedded designers to enhance efficiency, reduce system costs, and achieve higher safety levels for HEV/EV motor control systems.

Source: Renesas Electronics Corp.

Source: Renesas Electronics Corp.

The new RH850/C1x devices can be used with the RAA270000KFT RH850 family power supply management IC (PMIC), which is currently available in sample quantities. The power management IC integrates into one device all the power supply systems required for MCU operation, two external sensor power supply tracks, and a full complement of monitoring and diagnostic functions, significantly reducing the user burden associated with power supply system design.

The RH850/C1H and RH850/C1M MCUs incorporate large memory capacities achieved through 40 nm MONOS process technology. The RH850/C1x series is based on Renesas’s metal oxide nitride oxide silicon (MONOS) embedded flash, which has an extensive track record in mass production. The MONOS characteristics include fast readout, low power consumption, and large storage capacity. The RH850/C1M and RH850/C1H devices offer memory capacities of 2 MB and 4 MB, respectively. In addition, 32-KB data flash memory, with essentially the same functionality as EEPROM, is included for data storage.

The microcontrollers also feature an extensive set of peripheral functions for HEV/EV motor control. The RH850/C1x MCUs can implement three types of motor control in hardware: sine wave PWM, over modulation, and square wave.

Samples of the RH850/C1H and RH850/C1M MCUs are scheduled to be available from the beginning of 2015 and will cost $45 and $50 per unit, respectively. Mass production is scheduled for May 2016 and is expected to reach a scale of 100,000 units per month.

Source: Renesas Electronics Corp.

DIY Arduino-Based ECG System

Cornell University students Sean Hubber and Crystal Lu built an Arduino-based electrocardiography (ECG) system that enables them to view a heart’s waveform on a mini TV. The basic idea is straightforward: an Arduino Due converts a heartbeat waveform to an NTSC signal.

Here you can see the system in action. The top line (green) has a 1-s time base. The bottom line (yellow) has a 5-s time base. (Source: Hubber & Lu)

Here you can see the system in action. The top line (green) has a 1-s time base. The bottom line (yellow) has a 5-s
time base. (Source: Hubber & Lu)

In their article, “Hands-On Electrocardiography,” Hubber and Lu write:

We used the Arduino Due to convert the heartbeat waveform to an NTSC signal that could be used by a mini-TV. The Arduino Due continuously sampled the input provided by the voltage limiter at 240 sps. Similar to MATLAB, the vectorized signal was shifted left to make room at the end for the most recent sample. This provided a continuous real-time display of the incoming signal. Each frame outputted to the mini-TV contains two waveforms. One has a 1-s screen width and the other has a 5-s screen width. This enables the user to see a standard version (5 s) and a more zoomed in version (1 s). Each frame also contains an integer representing the program’s elapsed time. This code was produced by Cornell University professor Bruce Land.

As you can see in the nearby block diagram, Hubber and Lu’s ECG system comprises a circuit, an Arduino board, a TV display, MATLAB programming language, and a voltage limiter.

The system's block diagram (Circuit Cellar 289, 2014)

The system’s block diagram (Circuit Cellar 289, 2014)

The system’s main circuit is “separated into several stages to ensure that retrieving the signal would be user-safe and that sufficient amplification could be made to produce a readable ECG signal,” Hubber and Lu noted.

The first stage is the conditioning stage, which ensures user safety through DC isolation by initially connecting the dry electrode signals directly to capacitors and resistors. The capacitors help with DC isolation and provide a DC offset correction while the resistors limit the current passing through. This input-conditioning stage is followed by amplification and filtering that yields an output with a high signal-to-noise ratio (SNR). After the circuit block, the signal is used by MATLAB and voltage limiter blocks. Directly after DC isolation, the signal is sent into a Texas Instruments INA116 differential amplifier and, with a 1-kΩ RG value, an initial gain of 51 is obtained. The INA116 has a low bias current, which permits the high-impedance signal source. The differential amplifier also utilizes a feedback loop, which prevents it from saturating.

Following the differentiation stage, the signal is passed through multiple filters and receives additional amplification. The first is a low-pass filter with an approximately 16-Hz cutoff frequency. This filter is primarily used to eliminate 60-Hz noise. The second filter is a high-pass filter with an approximately 0.5-Hz cutoff frequency. This filter is mostly used to eliminate DC offset. The total amplification at this stage is 10. Since the noise was significantly reduced and the SNR was large, this amplification produced a very strong and clear signal. With these stages done, the signal was then strong enough to be digitally analyzed. The signal could then travel to both the MATLAB and voltage limiter blocks.

Hubber and Lu’s article was published in Circuit Cellar 289, 2014. Get it now!

New DSP “Lab-in-a-Box” for ARM-Based Audio Systems

Cambridge, UK-based, ARM and its partners will start shipping a DSP “Lab-in-a-Box” (LiB) to universities worldwide to help boost practical skills development and the creation of new ARM-based audio systems. This will include products such as high-definition home media and voice-controlled home automation systems. The LiB kits contain ARM Cortex-M4-based microcontroller boards by STMicroelectronics and audio cards from Wolfson Microelectronics and Farnell element14.ARMDSPLiBWeb

As the centerpiece of the ARM University Program, LiB packages offer ARM-based technology and high-quality teaching and training materials that support electronics and computer engineering courses. DSP courses have traditionally used software simulation packages, or hands-on labs using relatively expensive development kits costing around $300 per student. By comparison, this new DSP LiB will cost around $50 and will allow students to practice theory with advanced hardware sourced from widely-available products.

“Our Lab-in-a-Box offerings are proving hugely popular in universities because of the low-cost access to state-of-the-art technology,” said Khaled Benkrid, manager of the Worldwide University Program, ARM. “The DSP kits, powered by ARM Cortex-M4-based processors, enable high performance yet energy-efficient digital signal processing at a very affordable price. We expect to see them being used by students to create commercially-viable audio applications and it’s another great example of our partnership supporting engineers in training and beyond.”

The DSP LiB will begin shipping to universities in July 2014. It is the latest in a series of initiatives led by ARM which span multiple academic topics including embedded systems design, programming and SoC design. The DSP kits will also be offered to developers outside academia at a later date.