A differential pin pair can be used as a comparator to create a basic ADC. This app note shows how to design a low speed (1 KHz) and “high” speed (50 Khz) ADC technique using only FPGA pins, a resistor and a capacitor. Regardless of whether we ever use this technique, it is illuminating to understand how SAR and Delta Sigma ADCs are constructed:
A simple Analog to Digital Converter can be constructed by adding a small RC circuit to an LVDS input on an FPGA or CPLD…. The LVDS input will act as a simple analog comparator and will output a digital ‘1’ if the Analog Input voltage is higher than the voltage from the RC network. By changing the voltage on the input to the RC circuit, the LVDS comparator can be used to analyze the Analog Input voltage to create an accurate digital representation… A low frequency signal can be processed using a simple Successive Approximation Register… A higher frequency implementation…can be implemented using a Delta Sigma Modulator function, which consists of a sampling register and a Cascade Integrated Comb (CIC) Filter.
App note from OSRAM about IR LEDs and IR detectors used on touchscreen technologies. Link here (PDF)
Touchscreens as a popular user interface are more and more common. Applications span from public information systems to customer self-service terminals. Thus, as a logical step, more and more devices today feature this kind of user interface, e.g. bank automatic teller machines (ATMs), personal digital assistants (PDAs), mobile phones and PC displays. The widespread popularity is actively supported by standard computer based operating systems, such as e.g. Windows® 7.
The rapid development of CMOS imaging sensors and the development of high power infrared (IR) emitters in slim packages have led to a series of new optical touchscreen technologies. Many of them contain proprietary technology and solutions.
App note from Vishay Siliconix, giving us tips on powering FPGAs. Link here (PDF)
An FPGA is a device that offers many logic elements – up to 1 million gates in a single device at this writing – as well as other functionality such as transceivers, PLLs, and MAC units for complex processing. FPGAs are becoming very powerful, and the need to power the devices effectively is a key, if often underestimated, part of the design. A straightforward power supply design process can significantly reduce the number of required design iterations for the OEM designer.
Another app note from NXP describing the behavior of the SMARTMOS Dual 24 – 36 V high-side switch devices, at switch OFF when driving inductive loads. Link here (PDF)
These intelligent high-side switches are designed to be used in 24 V systems such as trucks and busses (XS4200). They can be used in industrial (XSD200) and 12 V applications as well. The low RDS(on) channels can control incandescent lamps, LEDs, solenoids, or DC motors. Control, device configuration, and diagnostics are performed through a 16-bit SPI interface, allowing easy integration into existing applications.
App note from NXP about the short-citcuit protection strategies of their MC12XS6 centralized automotive lighting drivers family IC. Link here (PDF)
The MC12XS6 devices include up to five self-protected high-side switches, with its extended protection and diagnostics, to detect bulb outage and short-circuit fault conditions. Additionally, this device incorporates a pulse width modulation control module, to improve lamp lifetime with bulb power regulation at no less than 25 Hz, and address the dimming application (daytime running light).
App note from Kionix on the introduction of most common method in determining orientation and rotations in an accelerometer. Link here (PDF)
The fact that accelerometers are sensitive to the gravitational force on the device allows them to be used to determine the attitude of the sensor with respect to the reference gravitational vector. This attitude determination is very useful in leveling or gimballing gyroscopes and magnetometers for use in compass and navigation instruments; determining tilt for game controller applications; and determining tilt or rotation for screen rotation of handheld devices. The method for calculating orientation or rotation depends on the specific application.
ON Semiconductors guide to cover much higher current capacity from eFuses. Link here (PDF)
The standard 12 V, 5 V and 3.3 V electronic fuses from ON Semiconductor provide overcurrent and overvoltage protection and come in different current limit configurations. As an example, the 5 V NIS5452 eFuse has a recommended operational 5 A current limit. Sometimes the operating current for the user system might be much higher than the maximum allowed current limit provided by the eFuse.
Tips and tricks from ON Semiconductors on how to optimize high output current switching regulators thermal dissipation. Link here (PDF)
As power demand in portable designs is more and more important, designers must optimize full system efficiency in order to save battery life and reduce power dissipation. Energy losses study allows knowing thermal stakes. Due to integration and miniaturization, junction temperature can increase significantly which could lead to bad application behaviors or in worst case to reduce components reliability.
App note from OSRAM on High-power LEDs and their special requirements. Link here (PDF)
In general high power emitters can be driven with DC currents in the range of 1 Ampere whereas most low power products like 5 mm Radials are limited to 100 mA.
As the light output increases with driving current the optical power is raised by a factor of ten compared to standard devices. At the same time much less board space is occupied as fewer devices are needed. On the other hand a careful thermal management is absolutely mandatory because the thermal power dissipation is increasing in the same way as the optical output power. To keep the junction temperature of the chip as low as possible a low thermal resistance is needed and the standard FR4-PCB has to be replaced by a metal core PCB. By this a high optical efficiency of the IRED can be achieved.
NXP’s app note on calculating inductor sizes using MC13783 PWM controller as example. Link here (PDF)
The purpose of this application note is to provide a method of choosing the size of the inductors for the optimized switching regulators versus the current consumption of the application. This will allow to optimize the size and the cost of these components.