Power Electronics

NEW products

Battery Charger IC

ADVANCED ANALOGIC Technologies' AAT3691 is a dual-input battery charger IC with integrated overvoltage protection (OVP) up to 28 V. Designed to meet industry requirements for highly flexible and reliable battery charging from multiple sources, the product supports inputs from both ac adapters and USB ports in handheld devices. In addition, the charger intelligently assesses which input source offers minimum charging time and modifies the charge path while the integrated OVP protects the battery and system against faulty input.

The AAT3691 is designed to regulate battery charge voltage and current for 4.2-V Li-ion battery cells used in a variety of portable systems. As an integrated battery charger IC that combines a power device, reverse current blocking and current sensing, the product is designed to operate from ac adapter inputs and USB ports across a 3-V to 6.75-V (typical) input voltage range. To maximize safety, the AAT3691 adds integrated OVP up to 28 V. The OVP block offers an extremely fast response of 1 < µs. Charge current can be programmed up to 1.6 A for charging via an ADP and up to 0.5A for charging via a USB port using external resistors. When ADP or USB input power exceeds 6.75 V typical, an internal series switch opens preventing damage to the battery or charging circuit. Charging and OVP total ON resistance (RDS(ON)) for the AAT3691 is 600 m max. Automatic charge selection circuitry recognizes the best charging source in terms of input voltage and other criteria and modifies the charge path to maximize charging efficiency. The AAT3691 also features a no-battery-present (NOBAT) input detection function that prevents input power from passing through the OVP block and suspends charging when no battery is present or a battery trace or connector is defective. Battery charging status is continually monitored for fault conditions, and safety features include thermal shutdown protection, power-on reset and soft start.

Qualified across the -40°C to +85°C temperature range, the AAT3691 is available in a 16-pin 3-mm × 4-mm TDFN package. It sells for $1.12 in 1000-piece quantities.
Advanced Analogic Technologies
Santa Clara, Calif.


PD Controller

LINEAR TECHNOLOGY'S LTC4265 802.3af/802.3at-compliant PoE interface controller is for high-power PD applications needing up to 25.5 W. Using the PoE+ standard, the device recognizes the PSE as Type 1 hardware complying with the IEEE 802.3af power levels or Type 2 hardware complying with IEEE 802.3 at power levels, allocating power accordingly. The 2-event hardware classification lets Type 2 PSEs identify connection to an 802.3at-compliant PD and provides a signal to the PD that can source the higher power levels associated with 802.3at power, ensuring interoperability between Type 1 and 2 devices.

The LTC4265 allows users to configure a classification load current that represents the PD power classification. Other features include a shutdown pin with signature corrupt for flexible auxiliary support and a 100-V MOSFET that isolates the controller and external dc-dc converter during detection and classification, while providing 100 mA of inrush current limiting.
Linear Technology
Milpitas, Calif.


Power Modules

POWERSEM GMBH has introduced two 3-phase bridge rectifier modules with a profile height of 17 mm. Models include the PSDS 62 — rated at 63 A at 110°C for versions rated at 800 V, 1200 V, 1400 V, 1600 V and 1800 V — and the PSDS 82, rated at 88 A at 110°C for versions rated at 800 V, 1200 V, 1400 V, 1600 V and 1800 V. Both modules features screw connections and the company's family of single- and 3-phase rectifier modules with screw, solder and fast-on connectors.

The 17-mm height modules follow the current trend in power modules, gradually replacing the 30-mm profile height standard. The new 17-mm bridge rectifiers allow new product designs to be slimmer while retaining the same power capacities. Per module junction-to-case thermal resistance for the PSDS 62 is 0.24 K/W and the PSDS 82 is 0.183 K/W. Modules are RoHS-compliant, and the company has applied for UL approval. Typical applications include motor drives, power supplies, battery chargers, uninterruptible power supplies (UPSs) and welding current sources.
Powersem GmbH
Schwabach, Germany



AVX CORP.'S high capacitance PulseCap capacitor features a low-profile package and is designed for applications such as PCMCIA/USB wireless express cards, where bulk capacitance is needed to boost transmitter power. These large case-size tantalum products are rated at 2200 µF (2.2 mF)/6.3 V. A maximum case height of 2 mm makes them suitable for reduced-height applications. The “undertab” termination style — where traditional “J” leads are replaced by terminations that do not protrude outside of the outline of the case — increases volumetric efficiency and allows parts to be positioned closely together, delivering significant space savings.

In addition, PulseCaps are RoHS compatible and capable of withstanding a soldering profile of 3× reflow at 260°C. Operating temperature range is -55°C to +125°C. Other applications include wireless data cards, metering and sensors. Pricing typically starts at $2.20 each.
AVX Corp.
Myrtle Beach, S.C.


Switching Regulator IC

TEXAS INSTRUMENTS' TPS61500 is a monolithic switching regulator with an integrated 3-A, 40-V power switch. A suitable driver for high-brightness 1-W or 3-W LEDs, the device has a wide input voltage range to support application with input voltage from multi-cell batteries or regulated 5-V, 12-V power rails. An external resistor sets the switching frequency between 200 kHz and 2.2 MHz. In addition, the IC operates from a 2.9-V to 18-V input range. Its internal power switch can drive four 3-W LEDs from a 5-V input and eight LEDs from a 12-V input. Power conversion efficiency is up to 93%.

The LED current is set with an external sensor resistor R3, and the feedback voltage is regulated to 200 mV by a current-mode PWM control loop. The device also supports analog and pure PWM dimming methods for LED brightness control. Connecting a capacitor to the DIMC pin configures the device to be used for analog dimming, and the LED current varies proportional to the duty cycle of an external PWM signal. Floating the DIMC pin configures the IC for pure PWM dimming with the average LED current being the PWM signal's duty cycle times a set LED current.

The device also features a programmable soft-start function to limit inrush current during start-up and has other built-in protection features, such as pulse-by-pulse overcurrent limit, programmable overvoltage protection and thermal shutdown.

The TPS61500 is available in a 14-pin HTSSOP package with PowerPad.
Texas Instruments



THE SI8422DB from Vishay Intertechnology is optimized for power amplifier, battery and load switching in portable devices such as cell phones, PDAs, digital cameras, MP3 players and smart phones. The 2-mil backside coating of the device insulates the top of the MICRO FOOT package to prevent electrical shorts from being created by temporary contact with moving parts in portable devices. This insulation allows the device to be used in applications with very thin height requirements, providing designers with the flexibility to place the MOSFET where other items may be directly above it, such as shielding, buttons or touch screens, which further compress the product height when depressed. This layout flexibility also translates into reduced parasitics, as the traces can be better optimized by not having to be routed to areas on the PCB with less height restrictions.

The 20-V n-channel Si8422DB features an ultracompact 1.55-mm ×1.55-mm footprint with a slim 0.64-mm profile. The device offers a low on-resistance range from 0.043 Ω at 1.8-V VGS to 0.037 Ω at 4.5-V VGS, with a maximum gate-source voltage of ±18 V.

Samples and production quantities of the Si8422DB are available now. Pricing for delivery in 100,000-piece quantities starts at $0.20.
Vishay Intertechnology
Malvern, Pa.


Intelligent Power Switches

THE FPF2024, FPF2025, FPF2026 and FPF2027 from Fairchild Semiconductor are IntelliMAX advanced load switches that minimize the quiescent current and prolong battery life. With a quiescent current of only 1µA, these advanced load switches use less than 2% of the current of alternate solutions whose quiescent current ranges from 60 µA to 80 µA. They also provide robust current limiting protection that prevents damage from adverse events associated with unexpected current surges.

The FPF202x series has a wide operating range (1.6 V to 5.5 V) to address the voltage specifications for biometric sensor modules found in laptops, ultra-mobile portable computers (UMPCs), smart phones and other portables. Packaged in 1.0-mm × 1.5-mm WLCSP packaging and bolstered with robust ESD protection (5.5 kV), these advanced load switches address the space and ESD protection concerns facing portable designs. In addition, the FPF2024, FPF2025, FPF2026 and FPF2027 use Pb-free terminals and have been characterized for moisture sensitivity in accordance with the Pb-free reflow requirements of the joint IPC/JEDEC standard J-STD-020. Price per unit in 1000 pieces is $ 1.49.
Fairchild Semiconductor
San Jose, Calif.


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