DC-DC Power Supplies
RECOM'S RCD series of constant current LED drivers has been extended to a maximum of 1,200 mA to provide the higher currents needed by the next generation of high brightness LEDs. The RCD-24-1.0 and RCD-24-1.2 dc-dc converters deliver a stable maximum current of 1 A or 1.2 A, respectively, from a wide input voltage range of between 5 V and 36 Vdc. Measuring 22 mm × 12.5 mm × 8.5 mm, they are fully complete plug-and-play units requiring no external components, thus reducing the circuit footprint compared with alternative discrete solutions by up to 50%.
In addition, the RCD series has two independent dimming inputs: a PWM control that allows simple interfacing with microprocessors and digital controllers, and an analogue voltage input that is suitable for lighting controllers or rheostat dimmers. Both dimming inputs are linear and the dimming range covers 0% to 100%. The PWM input also can be used to shut down the converter to draw only 200 µA from the supply.
According to the company, the feedback control circuit used in the RCD family of LED drivers ensures excellent load and current regulation, resulting in LED current stability of ±1%, a residual output ripple of less than 200 mV and efficiencies of up to 96%. The low internal power dissipation of 800 MW permits the ambient operating temperature range of -40°C to +71°C for the 1,000-mA version and -40°C to +65°C for the 1,200-mA version. The drivers also feature short-circuit protection, thermal shutdown and contain no electrolytic or tantalum capacitors.
LINEAR TECHNOLOGY'S LTC3605 is a high-efficiency, 4-MHz synchronous buck regulator that uses a constant frequency controlled on-time, current-mode architecture. The device delivers up to 5 A of continuous output current at output voltages as low as 0.6 V with minimum thermal derating from a 4-mm × 4mm QFN package. Operating from an input voltage of 4 V to 15 V, it is suitable for dual-cell Li-ion applications as well as fixed rail systems with voltages up to 12 V. The LTC3605's switching frequency is user-programmable from 800 kHz to 4 MHz, enabling the use of tiny low-cost capacitors and inductors.
In addition, the product uses internal N-channel switches with RDS(ON)s of 35 mΩ and 70 mΩ to deliver efficiencies as high as 96%. Its low minimum on-time allows low duty cycle operation at high switching frequencies. The LTC3605's PolyPhase operation (up to 12 phases) allows multiple regulators to be cascaded, running out-of-phase to minimize input and output capacitance. Current-mode operation offers fast transient response while simplifying compensation. Other features include output tracking and a shutdown current of only 15 uA.
Pricing for the LTC3605EUF starts at $4.25 each in 1,000-piece quantities and is available from stock.
THE FAN102 from Fairchild Semiconductor is a highly integrated PWM controller, featuring proprietary topology that enables simplified circuit design for battery charger applications. According to the company, a low-cost, smaller and lighter charger results when compared to a conventional design or a linear transformer. The startup current is 10 µA, which allows use of large startup resistance for further power savings.
To minimize the standby power consumption, the green-mode function provides off-time modulation to linearly decrease PWM frequency under light-load conditions. This green-mode function assists the power supply in meeting the power conservation requirements. Using FAN102, a charger can be implemented with fewer external components and minimized cost.
The FAN102 controller is available in 8-pin SOP package.
San Jose, Calif.
Front-End Power Supplies
THE EFE Series of embedded front-end power supplies includes the 300-W EFE-300 and the 400-W EFE-400. Both single-output power supplies deliver 133% peak-power capability for 10 sec and offer efficiency of up to 90%. In addition, the products employ an 8-bit microcontroller for full digital control of the output and to handle housekeeping routines, resulting in a 25% parts count reduction to achieve a 45% smaller and up to 56% lighter design compared to competitive products. Power densities of up to 22 W/in.3 are achieved under peak-load conditions and 16.6 W/in.3 under continuous loading. Featuring a 1U profile, the EFE-300 measures 3 in. × 5 in. × 1.34 in., while the EFE-400 measures 3 in. × 6 in. × 1.34 in.
Allegro's A4447 is a 2-A fixed off-time, current-mode-controlled buck-switching regulator. Featuring an 8-V to 50-V input range, the regulator requires an external clamping diode, inductor and filter capacitor, and the off time is determined by an external resistor. In addition, the device will operate in both continuous and discontinuous modes. An internal blanking circuit is used to filter out transients due to the reverse recovery of the external clamp diode. Typical blanking time is 200 nS, and the output voltage is adjustable from 0.8 V to 24 V, based on a resistor divider and the 0.8-V ±3% reference. Supplied in an eSOIC-8L package, the A4447 is priced at $0.62 in quantities of 1,000 and has a 12-week lead-time to market.
Vishay Intertechnology's SiA921EDJ extends the company's P-channel TrenchFET Gen III technology to ultrasmall packages for handheld electronics. The device is designed for use in dc-dc buck converters as well as load, PA and battery switches in portable devices In addition, the SiA921EDJ offers an ultralow on-resistance of 59 mΩ at 4.5 V and 98 mΩ at 2.5 V. The compact 2-mm × 2-mm footprint of the PowerPAK SC-70 is half the size of the TSOP-6, while offering comparable on-resistance. Halogen-free in accordance with IEC 61249-2-21, samples and production quantities of the SiA921EDJ TrenchFET power MOSFET are available now, with lead times of 10 to 12 weeks for larger orders. Pricing for 100,000-piece quantities starts at $0.15.
AC-DC Power Supplies
PHIHONG HAS expanded its adapter line to include the PSA12A-120-R and the PSA12E-120-R 12-W fixed-prong, wall-mount adapters for OEM applications. ENERGY STAR EPS 2.0-compliant, the 12-Vdc output adapters have been designed for use in the United States and Europe, respectively, and are suitable for wireless communications, networking, portable equipment, and peripheral applications.
Both devices are double-insulated and feature Class B EMI compliance, as well as a no-load power consumption of <0.3 W. The adapters are rated to operate between 0°C and 40°C and can tolerate up to 90% relative humidity. They also feature overvoltage and short-circuit protection. Additionally, the PSA12A-120-R bears cULus, PSE and BSMI safety approvals, while the PSA12E-120-R bears TUV and CE approvals.
The PSA12A-120-R adapter measures 2.81 in. × 1.33 in. × 2.74 in., including the ac input prongs, and weighs 3 oz. The PSA12E-120-R adapter measures 2.81 in. × 1.33 in. × 3.28 in., including the ac input prongs, and weighs 3 oz. Both adapters are terminated with a 2.1-mm × 5.5-mm dc output barrel connector.
Pricing for the PSA12A-120-R starts at $5.88 per unit at OEM quantities, and pricing for the PSA12E-120-R starts at $6.12 per unit at OEM quantities.
OPERATING FROM a 2.7-V to 5.5-V input voltage, the AAT2862 from Advanced Analogic Technologies is a lighting management unit (LMU) that drives up to eight LEDs and integrates four low-dropout (LDO) linear regulators. Optimized for single-cell Li-ion/polymer powered systems, the product's capabilities are suitable for I2C-based high-performance smart phones and other mobile devices that require the integration of two camera modules. The LMU also adds an automatic fade-in/fade-out backlight control that simplifies design and reduces processor overhead. To ensure constant current over the entire battery range, the LEDs are driven from a tri-mode charge pump that automatically switches between 1x, 1.5x and 2x modes to maximize operating efficiency. The charge pump's 1-MHz operating frequency permits the use of 1-µF ceramic capacitors. In addition, the eight LED outputs are programmable from 500 µA up to 30 mA. Two LED outputs can be programmed up to 60 mA each. Current can be set to any of 32 separate levels via an industry-standard I2C interface. To ensure uniform display brightness, current matching is better than 3%. To balance power dissipation, high current matching exceeds 5%.
Qualified across the -40°C to +85°C temperature range, the AAT2862 is available in a PB-free, 24-pin TQFN34 package.
Advanced Analogic Technologies
Santa Clara, Calif.
ADVANCED ANALOGIC Technologies' AAT3620 is the industry's first fully integrated single-cell Li-ion battery charger capable of supplying up to 2-A charge current. This dual-mode solution provides a high-efficiency switching charger during constant current (CC) and constant voltage (CV) mode. To minimize EMI and RFI emission, the device switches to linear mode during CV mode where power dissipation is at a minimum. Operating across a 4.3-V to 6-V input range, the device performs battery charging using a 1.5-MHz PWM converter. During CC and most of CV mode, the device delivers up to 2 A. When the current dips below 300 mA in CV mode, the device automatically switches to a low-noise linear mode, minimizing noise, EMI and RFI emission.
The product also features programmable end-of-charge using external resistor, built-in reverse blocking, a 1% constant voltage-mode regulation and an integrated programmable charging timer. Overvoltage, overcurrent and overtemperature protection circuits monitor charge state and battery charge temperature for fault conditions. The charger IC also adds a status monitor output pin to indicate battery charge status and power source status via a display LED. Qualified over a -40°C to +85°C temperature range, the AAT3620 is available in a 14-pin, 3-mm × 3-mm TDFN package. It sells for $1.60 in1,000-piece quantities.
Santa Clara, Calif.
MOLEX'S EXTREME Ten60Power family of high-power connectors can reach a current rating of 60 A per blade at a 30°C T-rise. Designed for use in power supplies, servers, routers, 1- and 2-rack unit (RU) modular enclosures, chassis-based systems, storage and industrial controllers, the connectors feature a modular high-current power and signal connector system in a co-planar and right-angle board-to-board orientation. The product also provides a maximum current-to-space ratio packaged in a low-profile, 10-mm (0.394-in.) tall housing design that enhances system airflow.
In addition, the EXTreme Ten60Power family's high-current contact blades in dc (5.5-mm) and ac (7.5-mm) spacing options provide design flexibility. Power blades are rated up to 60 A per blade, providing up to 260 A per linear inch of board real estate.
The high-current connector is available in one through 10 power blade modules and six though 36 signal modules along with either end-mount or top-mount guidance. Wire-to-board options are also available.
Available in a 7-pin SIL package, Ancrona's AMVR series of dc-dc converters accept input voltages of 5 V, 12 V, 15 V or 24 V and deliver output voltages of 5 V, 9 V, 12 V or 15 V with an output power up to 1 W. Line regulation is 0.5%; load regulation from zero load to full load is 1.5%. Additional features include low ripple and noise, an input-to-output isolation of 1,000 Vdc, MTBF >3,500,000 hr and an operating temperature range of -40°C to +85°C. Suitable for local generation of higher or inverted operating supplies for sensors, analog front ends in digital systems, for interface functions and MOSFET or IGBT drivers, they feature the industry-standard pin out and can replace unregulated dc-dc converters without PCB redesign. In addition, they are PB-free and RoHS-compliant.
Ancrona/Willi Bacher Gmbh
AVAGO TECHNOLOGIES' ACPL-570xL/573xL/177xL series includes single-, dual- and quad-channel hermetically sealed optocouplers capable of operation at temperatures ranging from -55°C to +125°C to meet the requirements of aerospace, industrial and military applications. These low-voltage optocouplers are also suitable for microprocessor system interfaces, process control input/output isolation, voltage level shifting and logic ground isolation.
Each channel of the ACPL-570xL/-573xL/-177xL optocouplers contains a GaAsP light-emitting diode (LED) that is optically coupled to an integrated high-gain photon detector. In addition, the high-gain output stage features open collector output, providing both lower saturation voltage and higher signal speed than is possible with conventional photo-Darlington optocouplers. The supply voltage for these devices can be operated at as low as 3 V without adversely affecting parametric performance.
The ACPL-570xL/-573xL/-177xL series is priced from $43 in 1,000-piece quantities.
San Jose, Calif.