Search results

Backlighting in portable device displays has historically utilized difficult-to-power cold cathode-fluorescent (CCFL) tubes. The tubes run on alternating current (AC) and need a large initial voltage of typically greater than 1 kV in order to fire them. Once they have fired: their operating voltage drops to under a kV. Because a notebook computer: for example: typically operates on low DC voltages (12V: 5V: 3.3V: etc.): a Royer oscillator must be used to transform this low voltage to the high-voltage AC required by the CCFL. The high voltages in the system are a potential safety hazard.The CCFL to LED conversion power supply reference design replaces the backlight CCFLs with strings of light-emitting diodes (LEDs). LEDs operate at low voltages of 3V TO 4V each and are extremely durable. They produce a brighter light whose spectral content can be more easily custom tailored to the needs of the backlight. Their brightness can be easily controlled to compensate for changes in ambient light. Also in contrast to the glass-tubed CCFLs: the physically small LEDs can be mounted on flexible strips: allowing the display to be more tolerant of and resistant to sudden shocks.The reference design: with National Semiconductor’s LM3431 three-channel: constant-current LED driver: uses two strings of six series-connected LEDs at a current of 30 mA per string. Each LED has a forward voltage drop of about 3.5V: making the total voltage across each string between 21V and 27V. With a 12V power source: the LM3431 is configured as a boost converter to generate this 21V to 27V output voltage.The design also includes a circuit utilizing a photodiode to make the brightness of the LEDs proportional to ambient light thus improving the readability of the display under all lighting conditions.

Application Note 972 Inter-Operation of Interface Standards

Communicating with the UCD9081; unpowered, in system.

This 600W wide voltage input dual phase power converter uses two emulated current-mode controllers 180 degrees out of phase to minimize input and output ripple current. Compared to conventional isolated power converters: this synchronous buck architecture provides a reduced footprint and BOM cost at higher levels of efficiency: greater than 97% over several operating conditions.

This reference design generates a 12V/16A output from a standard 48V DC telecom input. The UCC2897A controls an active clamp forward converter power stage. The low gate charge and low RDSon of the CSD19533Q51: implemented as self-driven synchronous rectifiers: allow this design to achieve a peak efficiency of 95%. The compact UCC27511 drivers simplify the gate drive circuitry for the synchronous rectifiers.

The MSP430 is typically used in applications such as metering, intelligent sensing, control systems and portable instrumentation. In some systems, the microcontroller may need to interface to an exter

This PMP4507 delivers 3.3V@3A or 5V@2A from a PoE source: standard 13W limit. The converter accepts also an external voltage from an adapter ranging 12V to 54V input.

This design is a digitally controlled: two phase interleaved: 700W power factor correction converter with added power metering functionality. A C2000™ Piccolo™ microcontroller is the controller for the two 180 ° phase shifted boost power stages that comprise the power factor correction converter: and: additionally: it monitors the line and neutral voltage waveforms to implement power metering functions. This design is able to achieve 97% efficiency and 1.5% THD at full load with power factor greater than 0.98. By minimizing power loss in the power stage: reducing reliability impacts of harmonic distortion: and providing near unity power factor: this design is a great choice for off-line applications and AC/DC power supplies.

The LTM9011-14/LTM9010-14/LTM9009-14 are 8-channel, simultaneous sampling 14-bit A/D converters designed for digitizing high frequency, wide dynamic range signals. AC performance includes 73.1dB SNR and 88dB spurious free dynamic range (SFDR). Low power consumption per channel reduces heat in high channel count applications. Integrated bypass capacitance and flow-through pinout reduces overall board space requirements.DC specs include ?1LSB INL (typ), ?0.3LSB DNL (typ) and no missing codes over temperature. The transition noise is a low 1.2LSBRMS.The digital outputs are serial LVDS to minimize the number of data lines. Each channel outputs two bits at a time (2-lane mode). At lower sampling rates there is a one bit per channel option (1-lane mode).The ENC+ and ENC? inputs may be driven differentially or single-ended with a sine wave, PECL, LVDS, TTL, or CMOS inputs. An internal clock duty cycle stabilizer allows high performance at full speed for a wide range of clock duty cycles.Applications Communications Cellular Base Stations Software Defined Radios Portable Medical Imaging Multichannel Data Acquisition Nondestructive Testing

This application report describes how to interface the DAC8574 digital-to-analog converter to the MSP430F449 mixed signal microcontroller.

This reference design: featuring the TLV320AIC3256 audio codec: is a fully-functional USB powered streaming audio platform that allows external audio sources to be connected to the USB port of a PC or laptop. User control is provided via a powerful: easy-to-use Windows-based GUI.Software development for the TLV320AIC3256 is supported through TI's comprehensive PurePath™ Studio Development Environment. A powerful: easy-to-use tool designed specifically to simplify software development on the TLV320AIC3xxx miniDSP audio platform. The Graphical Development Environment consists of a library of common audio functions that can be dragged-and-dropped into an audio signal flow and graphically connected together. The DSP code can then be assembled from the graphical signal flow with the click of a mouse.The USB Audio Reference Design is operational with one USB cable connection to a PC. The USB connection provides power: control: and streaming audio data to the EVM for reduced setup and configuration.