Product Overview on Allegro A4915

For our sixth discussion, we will be having Allegro's A4915: 3-phase MOSFET driver. But before we proceed, let us do some recap. First, we had Mouser's Micro-ElectroMechanical Systems. MEMS include accelerometers, gyros, inertial modules, and others alike. Second, we had IXYS' power electronics which drives various parts of heavy lifting machines. Third, we had IXYS' ultra-fast laser diode driver, the IXLD02. It is an ultra high-speed differential laser diode driver designed specifically to drive single junction laser diodes. Then, we discussed why Coilcraft Inductors' voltage ratings are not specified on datasheets. Lastly, we had Microchip's development platform with 2D multi-touch and 3D gestures.

Allegro's A4915 is designed for PWM current control of 3-phase brushless DC motors. It is capable of high current gate drive for 6 all N-channel power MOSFETs. An internal charge pump ensures gate drive down to 7 V supply and provides limited gate drive down to 5 V. A bootstrap capacitor is used to generate a supply voltage greater than the source voltage of the high side MOSFET, required for N-channel MOSFETs.

 
Internal synchronous rectification control circuitry is provided to improve power dissipation in the external MOSFETs during PWM operation. Internal circuit protection includes latched thermal shutdown, dead time protection, and undervoltage lockout. Special power up sequencing is not required.

 
The A4915 is supplied in a 28-pin TSSOP with an exposed thermal pad (suffix LP) and a 28-contact 5 × 5 mm QFN with an exposed thermal pad (suffix ET). These packages are lead (Pd) free, with 100% matte-tin leadframe plating.


To view the video about Allegro's A4915, click on the link below:
http://www.eeweb.com/company-blog/allegro_microsystems/allegro-a4915-product-overview/

Development Platform with 2D Multi-Touch and 3D Gestures

For this week, we already discussed about Mouser's MEMS, both IXYS' power electronic ICs and ultra-fast laser diode drivers, and Coilcraft's inductors. So then, let's do a recap.

First, we discussed about Mouser Electronics' MEMS which enable medical innovation. MEMS sensors give consumers great time using its advanced features. MEMS, Micro ElectroMechanical Systems, are now on almost all electronic equipments, from consumer electronics, to home appliance, and now even reinventing and improving medical equipments.

Second, we had power electronic components for materials handling. Power electronics may be small but these components help drive heavy machinery. Variety of drives can be found in lift trucks, and other materials handling equipment. They supply the mechanical energy to move the motors for hydraulic pump and propulsion, even used as auxiliary actuators for steering.


Third, we had ultra-fast laser diode drivers. Technically, it is an ultra high-speed differential laser diode driver designed specifically to drive single junction laser diodes in a differential fashion. Theoretically, laser diode drivers work in two ways: 1) produce constant regulated voltage; 2) produce constant current drive though the laser diode load. 

Fourth, we discussed about why datasheets for inductors do not indicated voltage rating. The voltage rating of an inductor is the maximum voltage that can be applied to the terminals without causing arcing or insulation breakdown. Voltage above the maximum rating may cause short circuits between turns, through the insulation, or from the windings to core or frame.

Now, we will discuss about the development platform with 2D multi-touch and 3D gestures. Microchip Technology's human interface input sensor, the 3DTouchPad. 3DTouchPad is Microchip's is a personal computer peripheral used to extend a 2D touch pad with 3D free space gestures. This component utilizes Microchip's projected capacitive (PCAP) sensor as well as Microchip's 3D gesture technology, GestIC®.

The 3DTouchPad offers all features expected from a touch pad (precision, multi-finger tracking, multi-finger surface gestures, such as swipes and scrolling) to which it adds 3D hand gestures. It enables a more efficient, more productive usage of the touch pad area. For example, the 3DTouchPad will allow the user to control the flow of pictures by a wave of the hand or to control the volume of the speakers with a casual rotation.

No driver installation is needed for the 3DTouchPad; it will simply work out-of-the-box. 


The 3DTouchPad is designed to be a comprehensive development platform, offering a fully documented Software Development Kit (SDK) as well as an Application Programming Interface (API). The SDK contains reference code and enables the development of applications, drivers and games.

The 3DTouchPad consists of a single four-layer PCB enclosed by a plastic housing. The mini USB port provides connectivity to a USB port of a PC. Three LEDs indicate the operating modes: 2D, 3D and Debug mode. 


Hardware Setup

The 3DTouchPad PCB contains the 2D touch pad surrounded by the electrodes for 3D gesture recognition. The assembly is placed on the bottom of the PCB. Figure 4 shows the assembly as well as the electrode structures.

3D gesture recognition is realized with Microchip’s single-chip gesture solution, MGC3130. The MGC3130 is a gesture recognition, motion tracking and approach detection controller based on Microchip’s patented GestIC technology. It enables user command input with natural hand movements while utilizing the principles of electrical near-field sensing. 


MGC3130 is connected to four Rx frame electrodes (North, East, South and West) located at the top of the PCB and one transmit (Tx) electrode which covers a full middle layer of the PCB. The four Rx electrodes define the edges of the 3D sensing space (X and Y direction). 


To learn more about the Development Platform with 2D Multi-Touch and 3D Gestures, click on the link below:
http://www.eeweb.com/company-news/microchip/development-platform-with-2d-multi-touch-and-3d-gestures/

 

Working Voltage Ratings for Inductors

The first 3 posts we had, we discussed about MEMS, Power Electronic Driver ICs, and Laser Diode Drivers. First, we had MEMS enable medical innovation. These systems make medical equipments more efficient and life-saver. Second, we had power electronic components for materials handling. Power electronics may be small but these components help drive heavy machinery. Variety of drives can be found in lift trucks, and other materials handling equipment. Then we had differential ultra-fast laser diode driver. Technically, it is an ultra high-speed differential laser diode driver designed specifically to drive single junction laser diodes in a differential fashion.

Next up, do you know why voltage rating are not specified on inductor data sheets? Well, voltage ratings of other electronic component are always indicated in the data sheets. It is a requirement. But inductors are different, voltage ratings are not specified on the data sheets. 

Definition of Voltage Rating 

The voltage rating of an inductor is the maximum voltage that can be applied to the terminals without causing arcing or insulation breakdown. Voltage above the maxi- mum rating may cause short circuits between turns, through the insulation, or from the windings to core or frame. 


Calculation 


The large number of construction variables – turn count, wire insulation type and thickness, the layering of the windings, bending or forming crossover leads – makes it difficult, if not impossible, to calculate the theoretical voltage limit of an inductor. 


For example, there are standard test methods for determining the voltage rating of film insulated magnet wire, which generally has a voltage rating in the hundreds, if not thousands, of volts. This rating can easily be compromised by the wire forming process necessary to wind an inductor. Magnet wire can be stressed, crazed or nicked, even in a carefully controlled manufacturing environment. A small scratch in the wire can cause arcing or breakdown at a voltage much lower than the wire "catalog" rating. To calculate a rating that includes these variables is not practical. 

Conclusion (The Good News) 

It might seem that choosing an inductor is nearly impossible. The good news is that all the factors that make it difficult to test or calculate an inductor voltage rating make it unnecessary to test. The vast majority of applications require inductors to be operated at very small working voltages - usually just a few volts. Remember, most inductors work by impeding current flow, not through high voltage induction. Almost all commercial inductors are good for a few volts or even tens of volts with no worries. So for most applications, inductor voltage rating is not a concern. 

For applications that operate from high line voltages or work by induction of high voltage across the winding, it is necessary to consider the possible breakdown of the inductor windings. In these cases it is recommended that the specific application be discussed with the inductor designer/manufacturer and a test plan developed to ensure the suitability of the inductor. 

To learn more about Working Voltage Ratings for Inductors, click on the link below:
http://www.eeweb.com/company-blog/coilcraft/working-voltage-ratings-for-inductors/
 

Differential Ultra Fast Laser Diode Driver

Before we go on, let's do some recap. We discussed about MEMS enable medical innovation and power electronic components for materials handling.

First, we discussed about Mouser Electronics' MEMS which enable medical innovation. MEMS sensors give consumers great time using its advanced features. MEMS, Micro ElectroMechanical Systems, are now on almost all electronic equipments, from consumer electronics, to home appliance, and now even reinventing and improving medical equipments.

 
Second, we had power electronic components for materials handling. Power electronics may be small but these components help drive heavy machinery. Variety of drives can be found in lift trucks, and other materials handling equipment. They supply the mechanical energy to move the motors for hydraulic pump and propulsion, even used as auxiliary actuators for steering.

 
Now, we will be discussing about IXYS' differential ultra fast laser diode driver, the IXLD02. Technically, it is an ultra high-speed differential laser diode driver designed specifically to drive single junction laser diodes in a differential fashion. Theoretically, laser diode drivers work in two ways: 1) produce constant regulated voltage; 2) produce constant current drive though the laser diode load. It is a constant current source, linear, noiseless, and accurate, that delivers exactly the current to the laser diode that it needs to operate for a particular application.

The IXLD02 is an ultra high-speed differential laser diode driver designed specifically to drive single junction laser diodes. Complementary sink outputs are provided via a low inductance multi-pin topology. These two signals make their transitions at the same time with transition times in the picoseconds. This technique provides the highest possible slew rate across the diode.

These performance features are combines with frequency agility to a maximum operating frequency of 17 MHz, a minimum pulse width of <1.5 ns and rise and fall times of approximately 600 ps. In addition, the pulse width and the current programming can be modulated in real time to >10 MHz. The IXLD02 is assembled in a high power SO-28 surface mount package.


Features

• Ultra Fast Pulsed Current Sink
• 17 MHz maximum operating frequency
• <1.5 ns Minimum Pulse Width
• 600ps Rise and fall times
• Pulse Width and Frequency agile
• Real Time Electronic Programming of Current and Pulse Width
• Low Inductance High Power Package Design
• Simultaneous Frequency, Pulse Width and Amplitude Modulation

To learn more about IXYS' ULTRA-FAST LASER DIODE DRIVER, click on the link below:
http://www.eeweb.com/company-news/ixys/differential-ultra-fast-laser-diode-driver/

Power Electronic Components for Materials Handling

This week, we will be discussing about various technological breakthroughs. First, we discussed about Mouser's MEMS on medical equipments. MEMS made the medical equipments, nowadays, more accurate and precise. CPRs, ultrasound machines, and other hospital equipments are vital in saving lives of all. In making those machines more accurate and precise, minimal to zero fatality will be met. Now, we will be discussing about new power electronic components for materials handling drive systems.

Power electronics may be small but these components help drive heavy machinery. Variety of drives can be found in lift trucks, and other materials handling equipment. They supply the mechanical energy to move the motors for hydraulic pump and propulsion, even used as auxiliary actuators for steering.

The majority of the electric drives under consideration makes use of AC or DC motors, additional types such as switched reluctance machines are presently gaining importance. Figures 2, 3, and 4 show schematics with a symbol of the respective machine, connected to an appropriate power section.

Power Semiconductor

Blocking voltage of the MOSFETs and possibly the diodes depends on battery voltage UZ in the intermediate circuit; there are several dominating levels: Automotive or truck like lead acid batteries are 12V or 24V versions, which is intended to be complemented by 42V in future. Besides, higher battery voltages up to some 100V are frequently used in industrial vehicles. The required rated blocking voltage is determined by the sum of battery voltage UZ and possible overvoltages. To minimise the latters within power section in switching operation, it is advantageous if phaseleg or chopper circuits are integrated in a single component with an internal low inductive current path. Besides, avalanche rated MOSFETs are able to dissipate some amount of energy, stored in the inevitable parasitic inductance of commutation path.

 

Semiconductors' required current ratings are determined by the power rating of the drive at nominal and overload. Each switch should be capable to conduct and control the required current at defined ambient conditions, the most important of which is temperature: In particular conduction and switching of the power semiconductor chips lead to power losses. The heat to dissipate is transferred from the component via the heatsink to ambient. This may not lead to a chip junction temperature exceeding the rating of the component. These considerations make trench MOSFETs a preferred choice for battery supplied industrial vehicles: This technology reduces the length of the current path in vertical power MOSFET chips and thus leads to a low on state resistance RDSon, while a sufficient switching speed for the typical frequencies of several kilohertz is maintained; it is particularly suitable for blocking voltages of up to some 100V...200V. In chopper circuits trench MOSFETs may advantageously be complemented by Schottky diodes with low forward voltage and fast switching capability. To optimize efficiency of the drive, which is an important feature of industrial vehicles influencing the operation time, it may be favorable to make a low on state resistance RDSon or high current rating respectively reduce conduction losses.

To learn more about Power Electronic Components for Materials Handling, click on the link below:

http://www.eeweb.com/company-blog/ixys/power-electronic-components-for-materials-handling/

MEMS Enable Medical Innovation

This week, we will be having a new variety of technological breakthroughs from various electronics manufacturers. First up, we'll discuss about Mouser Electronics' MEMS. Motion sensing, including accelerometers, gyroscopes, and inertial modules are examples of Mouser's Micro-ElectroMechanical Systems.

MEMs motion sensors are commonly used in consumer applications like smartphones, tablets, gaming devices, remote control (gesture recognition and pointing), notebooks, ultrabooks, and cameras. MEMS is also used in fitness and wellness applications like athlete performance monitoring, watches and PND, treadmills, and even barbells. Well, without our knowledge, they are even on our home appliances, cars, and hospital equipments, even industrial plants rely on them.

Medical or hospital equipments nowadays need to be accurate and precise especially for critical condition equipments. Cardio-Pulmonary Resuscitation (CPR), Magnetic Resonance Imaging (MRI), Computerized Tomography Scan (CT Scan), and others alike need to be accurate and precise in order to have a better result. Technological advances in hospital equipments. Accurately determining position of imaging and scanning equipments and precise repetition rate of CPRs can save so many lives with minimal to zero fatality.

Complex Motion Requires Precision Sensors and Embedded Sensor Processing


While simple motion detection, linear movement along one axis, for example, is valuable to a number of applications, such as detecting whether an elderly person has fallen, a majority of applications involve multiple types and multiple axes of motion. Being able to capture this complex, multidimensional motion can enable new benefits while maintaining accuracy in the most critical of environments. In many cases, it is necessary to combine multiple sensor types—linear and rotational, for instance—in order to precisely determine the motion an object has experienced. As an example, accelerometers are sensitive to the Earth’s gravity, so they can be used to determine inclination angle. As a MEMS accelerometer is rotated through a ±1-g field,(±90°), it is able to translate that motion into an angle representation. However, the accelerometer cannot distinguish static acceleration (gravity) from dynamic acceleration. In the later case, an accelerometer can be combined with a gyroscope, and post-processing of both devices can discern the linear acceleration from the tilt,based upon known motion dynamics models. This process of sensor fusion obviously becomes more complex as the system dynamics (number of axes of motion, types, and degrees of freedom of motion) increase. It is also important to understand the environmental influences on sensor accuracy. Temperature is obviously a key concern and can typically be corrected for; in fact, higher precision pre-calibrated sensors will dynamically compensate themselves. A less obvious factor to consider is the potential for even slight vibrations to produce accuracy shifts in rotational rate sensors. These effects, known as linear acceleration and vibration rectification, can be significant depending on the quality of the gyroscope. Sensor fusion improves performance by using an accelerometer to detect linear acceleration and compensate for the gyroscope’s linear acceleration sensitivity.


For many applications, particularly those requiring performance beyond basic pointing (up, down, left, right) or simple movement (in motion or stationary), multiple degrees-of-freedom motion detection is required. For example, a six degree-of-freedom inertial sensor has the ability to detect linear acceleration on each of three (x, y, z) axes and rotational movement on the same three axis, also referred to as roll, pitch, and yaw, as depicted in Figure 2.

 

Enabling High Value Medical Applications with Precision MEMs Sensors


MEMS inertial sensing is a highly mature technology in terms of both commercial viability and reliability. Beyond the well known use cases in mobile devices and gaming, significantly more challenging needs exist in the medical and industrial fields. In these cases, substantially higher performance is required, along with much more complete integration and sensor processing. The complexity of motion involved in medical navigation, for instance, dictates the need for starting with highly stable inertial sensors as a foundation, then building on this with optimized integration, sensor processing, and fusion. The availability of highly accurate and environmentally robust sensor developments is driving a new surge in the adoption of MEMS inertial sensors within the medical field. These inertial MEMS devices are capable of offering advantages in precision, size, power, redundancy, and accessibility over existing measurement/sensing approaches. Fortunately, many of the principles required for solving these next-generation medical challenges are based on proven approaches from classical industrial navigation problems, including sensor fusion and processing techniques.


To learn more about the MEMS Enable Medical Innovation, click on the link below:
http://www.eeweb.com/company-blog/mouser/mems-enable-medical-innovation/ 

MCU with Amplifier and Playback Function

Before we go to our last discussion for this week, let us do the recap. On the first post, we discussed Microchip's low-cost 8-bit PIC® microcontrollers that features a dual ADC peripheral. Second, we discussed Intersil's highly integrated li-ion battery charger. It is a complete battery charging solution for both li-ion and li-polymer batteries. Then, on the third post, we discussed ROHM's breakthrough in the field of wearable devices. ROHM was able to design a key-shaped sensor device, combining sensors from ROHM and Kionix with LAPIS Semiconductors Bluetooth® LE communication IC and sensor hub microcontroller. On our recent post, we discussed about ROHM's power management ICs designed for Intel Atom E600.  

For our last discussion, we will be dealing with ROHM's microcontroller with amplifier and playback function. It is a low power MCU that integrates an 8-bit low power MCU core, speech synthesis circuit, high efficiency Class D speaker amplifier, non-volatile memory, and oscillator circuit on a single chip, making audio playback possible by simply connecting to a speaker. ROHM ML610Q304 also provides hardware-based audio playback operation that minimizes the load placed on the MCU for system control processing. Its newly designed high-efficiency Class D amp reduces current consumption during audio playback by approx. 40% while maintaining volume and is easier to incorporate into battery-driven devices.

 Key Features

1. Hardware-based voice playback function simplifies design
Voice playback operation is performed using hardware, which significantly lightens the load on the MCU for system control processing and simplifies playback considerably.

2. 40% less current consumption during voice playback (vs. our conventional products)
A class-leading low power consumption 8bit microcontroller is integrated along with a newly developed Class D speaker amp that provides digital output, resulting in higher power efficiency and 40% less current consumption during voice output compared with conventional analog Class AB speaker amps – while maintaining volume levels. (*based on LAPIS Semiconductor evaluation criteria).

3. Monolithic design with integrated microcontroller and audio playback function reduces the number of parts required and contributes to device miniaturization
All functions required for audio playback are incorporated into a single chip, including a low-power MCU, speech synthesis circuit, high efficiency Class D speaker amp, non-volatile memory, and high accuracy oscillator circuit. Offered in a compact (5mm x 5mm) 28pin package (WQFN) that contributes to end-product miniaturization.

4. Multiple fail-safe functions provide superior reliability
(1) Speaker terminal disconnection detection
Detects no-playback condition due to disconnection between the microcontroller and speakers by monitoring for changes in resistance value between the speaker terminals and can alert users beforehand by lighting up LEDs.

(2) Speaker terminal short-circuit detection
Detects no-playback condition due to short-circuit by monitoring the voltage level of the speaker terminals and shuts down operation in order to prevent possible damage.

(3) Class D speaker amp overcurrent prevention
Ensures that the sound generator circuit (PWM circuit) does not stay fixed at the H level for over a specified amount of time in order to prevent excessive heat generation due to overcurrent.


To learn more about ROHM's MCU with Amplifier and Playback Function:
http://www.eeweb.com/company-news/rohm/mcu-with-amplifier-and-playback-function