Power Electronics

Energy Management Unit Reduces Power Consumption in Handhelds

National Semiconductor has announced the digitally-controlled PowerWise energy management unit (EMU), an integrated circuit that reduces the power consumption of digital processors used in battery-powered handheld consumer products. The LP5550 EMU, used in conjunction with National's advanced power controller (APC) and intelligent energy manager (IEM) technology from ARM, reduces the power consumption of digital processor cores by up to 70%. The LP5550 and APC also support the PowerWise Interface (PWI) open-industry standard introduced by National Semiconductor and ARM.

National's LP5550 enables a digital processor to adaptively adjust its supply voltage to the minimum level needed, greatly reducing its power consumption. The LP5550 includes an adaptive-supply-voltage buck regulator for the processor core and three additional fixed-voltage regulators. The fixed-voltage regulators power the input/output ring, oscillator/phase-locked loops (PLL) and memory on a low-power system-on-chip (SoC). The PWI interface controls the LP5550's functions for simple interfacing to the digital processor.

The LP5550 supports the PWI interface, a 2-pin, high-speed serial power management control interface for advanced processor power management. To enable adaptive voltage scaling, the LP5550 includes a digitally controlled, 300-mA, 0.6-V to 1.2-V buck regulator with up to 90% efficiency.

In addition, it has three programmable low drop-out (LDO) regulators with output voltages ranging from 0.6 V to 3.3 V. One LDO supports 100 mA and the other two support 250 mA. Input voltages range from 3 V to 5.5 V.

Packaged in a small footprint, lead-free, 16-pin LLP package, the LP5550 has excellent package thermal characteristics. The LP5550 is available now and is priced at $4.50 in 1000-unit quantities. Lead-free package options also are available.

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