Portable Power Management at Techno Frontier

July 21, 2011 by Jeff Shepard

A variety of products and technologies targeted at power management in portable devices were on display at Techno Frontier. Toko, Fujitsu Semiconductor and Toshiba Semiconductor were a few of the companies targeting portable applications. Toko demonstrated wireless charging modules, Fujitsu announced two new dc-dc converters and Toshiba expanded its offering of MOSFETs.

The Toko booth featured a demonstration of wireless inductive charging technology. Wireless inductive charging is a relatively new category for portable power management and Toko announced cumulative shipment of over 15 million units of its wireless power transmission module. Toko also announced a new generation of modules with higher-voltage and higher-current capabilities. The new modules can deliver up to 800mA at up to 12Vdc, with an overall power limitation of 4W.

The previous-generation modules operate over an input voltage range of 10.8-13.2Vdc and produce an output voltage greater than 3Vdc, generating a current of 75mA across a gap of 4mm. While the previous-generation modules are designed for trickle charging various battery-powered devices, the newest modules are capable of much higher charge rates.

Fujitsu was demonstrating dc-dc converters optimized for specific portable power applications. The MB392A02A is a 2-channel dc-dc buck converter IC with synchronous rectification and two built-in LDOs Designed to operate over a voltage range of 5.5-28Vdc, this device is offered in a QFN28 package. With an adjustable frequency of 100-600kHz, the outputs can deliver 50mA at 3.3Vdc and 100mA at 5Vdc.

In addition, Fujitsu announced the MB39C326 6MHz, buck-boost dc-dc converter optimized for powering the RF amplifier in mobile devices powered by a single Li-ion cell. These devices can provide output voltages from 0.4-4.5Vdc and operate over an input voltage range of 2.5-4.8Vdc. The output voltage is set with an external resistor. The device operates with a 0.5 uH inductor and is offered in a 20-pin plastic WLP package.

Toshiba Semiconductor announced the addition of the SSM6P47NU and SSM6P49NU to its lineup of small signal MOSFETs. Targeted at use in charging circuits for mobile devices, these dual P-channel MOSFETs feature lower on-resistance compared with previous-generation devices.

Toshiba’s SSM6P47NU and SSM6P49NU address the demand for compactness by combining two independent transistors into a UDFN6 package (2.0 x 2.0mm). A 1.8Vdc drive, combined with a 4A drain current allow the SSM6P47NU and SSM6P49NU to run at a high rate of efficiency, enabling batteries to be fully charged in less time. In addition to being used charging circuits the new devices are capable of acting as a switch to control which loads are connected or disconnected from the circuit.