Powering Multi-Functions

As with most electronic products and components, the pervasive trend is toward greater complexity and multiple functions. And of course, everything has to get smaller. In the handheld market, multiple functions mean multiple voltage levels. "With many handheld devices — such as the Apple iPhone — you have graphic processes in there as well as video images and computer power to enable speed," says Tony Armstrong, product marketing manager for power products at Linear Technology Corp. "That means there is an increasing number of voltages. And all of those functions have to be powered by a lithium battery." He says consumers want a device that has meaningful levels of integration without performance compromises. He says Linear's LTC3555 was developed as a response to the increasing demand for sophisticated power management.

LTC3555 Provides Multi-function Power Management

Linear Technologies Corp.'s LTC3555 switch node USB power manager and triple buck regulator for Li-ion/polymer battery applications offers fast charge time while minimizing heat. The tool integrates a switching PowerPath manager, a standalone battery charger, an ideal diode, 12C control, three high-efficiency synchronous buck regulators, plus an always-on LDO, all in a compact, low-profile 4 × 5 mm QFN package.

The LTC3555's PowerPath control feature is designed to seamlessly manage power flow between an ac wall adapter or USB port, Li-ion battery and system load while its "instant-ON" operation ensures system load power even with a dead or missing battery. For fast charging, the LTC3555's switching input stage converts nearly all of the 2.5W available from the USB port to charging current, enabling up to 700 mA from a 500 mA limited USB supply and up to 1.5A when wall-powered. An internal 180V ideal diode plus optional external idea diode controller provide a low loss power path, further minimizing heat generation and maximizing efficiency.

The LTC3555's three integrated synchronous buck regulations feature 100 percent duty cycle operation and are capable of delivering output currents of 1A/400 mA/400 mA, respectively, with adjustable output voltages down to 0.8V.

New AC Power Management Controller

Otek Corp. has developed its new PMC series. The controller replaces up to 30 individual meters and shrinks the panel size from several square feet to less than 19 sq inches. The depth behind the panel is only 2 sq inch. The PMC front has four 4-digit color-coded displays, a 6-digit large display with an exponential digit on its upper right. The unit has 42 LED annunciators for illumination for engineering units and a large super-bright LED for ground Fault warning or other indication.

The PMCs offer a phase-to-phase, phase-to-ground volts, amps, lead, LAG, SAG and PEAK. The product also has a Julian real-time clock for date and time stamp, as well as I/O synchronization pulses. The PMC also monitors the earth ground to system ground integrity to prevent lethal high voltage exposure to operators. The system will provide an alarm or shutdown if there is a potentially lethal occurrence. Another dry contact input accumulates the number of breaker's openings for preventive replacement before power outage.

Buck Regulators for Point-of-load Power Supply

National Semiconductor Corp. has introduced flexible high-performance synchronous buck regulations for point-of-load power supply designs. The 10 new regulators include peak-current-mode control technology and feature high-output accuracy. The regulators provide dc-dc power conversion for power supply designs in communication, data storage, industrial and automotive applications. The highly integrated regulators are offered with a variety of input voltages and output currents. They include peak-current-mode control technology that provides load transient response in low-duty cycle applications.

The LM201 and LM202xx synchronous buck regulator family includes 2, 3, 4 and 5A output current devices. Each regulator integrates two switching MOSFET's and utilizes an externally compensated peak current mode control loop. The external compensation allows the performance to be optimized for the output capacitor and inductor. With the current mode control, just two external components are needed for compensation. Each buck regulator has a precise internal voltage of 1.5 percent accuracy from -40C while providing excellent line and load regulation.

Engine Management Applications

Freescale Semiconductor has added six analog products to its SMARTMOS line of engine management applications. Engine control modules require diagnostics and specialized control functions to monitor environmental inputs and control complex loads while operating in harsh automotive environments. Freescale has added analog products for high-current powertrain applications, including output drivers, signal monitoring and conditioning devices and H-bridges. These products can be mixed and matched with Freescale's complementary MPC55xx 32-bit microcontrollers (MCUs), providing the flexibility to support a wide variety of multi-cylinder engine control applications.

Built on Power Architecture technology, MPC55xx MCUs are fully synthesizable system-on-a-chip devices optimized for automotive applications, including powertrain control. "Engine control complexity will continue to increase as next-generation systems are developed to meet tighter future emission legislation limits," says Chris Webber, vice president of Strategy Analytics Automotive Practice. "Mixed-signal interfacing between sensors and actuators and the engine MCU accounts for a significant amount of the circuit design complexity and cost. To control costs while delivering enhanced performance, electronic module engineers are looking for high levels of design flexibility and feature integration within standard IC products.

HDMI Transmitter Features On-Chip Control Support

Analog Devices Inc. has produced a low-power, high-definition multimedia interface (HDMI) v1.3 transmitter for portable media and DVD players, video recorders and other mobile multimedia devices that is capable of supporting high-definition audio and video content. The ADV7520NK is designed to simplify portable HDMI product design by integration consumer electronic control functions, allowing end users to command multiple devices with one remote. The transmitter incorporates a consumer electronic control (CEC) buffer on-chip, which reduces component count, eases design complexity and speeds time-to-market for portable high-definition devices by eliminating the need for the design engineer to develop a separate CEC support channel.

The ADV7520 adds CEC support to the low-power design of Analog's AD9387NK HDMI transmitter, which enables longer-running battery-powered video devices. It includes 5V-tolerant I/Os that support 12C and hot plus direct. This further simplifies system design and extends battery life in portable electronics by eliminating external voltage translator chips to convert these I/O signals from 5V to either 1.8 or 3.3V.

Ultra-low-power Transceiver

Maxim Integration Products has introduced the MAX2830o, a single-chip, direct-conversion, ultra-low-power 802.11g/b RF transceiver with integrated power amplifier, Rx/Tx/antenna diversity switches and crystal oscillator circuitry. The integration of Rx/Tx and antenna diversity switches saves 10 mm² of board space while driving down costs. The low-cost and small size of this integrated transceiver makes the MAX2830 ideal for Wi-Fi, PDA, VoIP and cellular handset applications. The MAX2830 also integrates digitally controlled crystal oscillator circuitry to implement the reference oscillator function, thus allowing the use of small, low-cost low-power crystals.

The MAX2830 is designed using Maxim's high-performance SiGe BiCMOS process. The transceiver operates from a 2.7 to 3.6V supply and the PA operates from 2.7 to 4.2V, which allows the MAX2830 to be powered directly from cell phone batteries. The receiver consumers 62 mA of current in receive mode, while achieving a low-noise figure of 3.3 dB, thus enabling best-in-class receive sensitivity of -75 dBm (64 QAM OFDM) without an external LNA. Additionally, the transmitter and PA deliver linear transmit power of +17 dBm (64 QAM OFDM) after the switch.