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Software becomes manager of power

Posted: 16 Mar 2004 ?? ?Print Version ?Bookmark and Share

Keywords:dc/dc? converter? power management? ldo? low drop-out?

The biggest roadblock to continuing integration of highly mobile devices is not highly sophisticated ASICs or even RF functions, but the cloud of analog and simple digital functions necessary to support the SoC and RF components. Power has to be turned on, regulated and turned up or down to optimize energy consumption; audio signals must be amplified; batteries have to be charged and monitored. In early designs, each of those functions required a small mixed-signal IC and a few supporting discrete components.

Austriamicrosystems AG, a mixed-signal chip design and manufacturing company, addressed this problem with the AS3601 power-management chip, which pulled many of the necessary functions together in an integrated, configurable platform. Now it has gone one step further with the AS3603, which brings power supply functions, power amp and battery management together under full software control.

Two efficient DC/DC converters and a charge pump provide fundamental voltages to a system. These are regulated through a bank of software-controlled low-dropout (LDO) regulators--one to drive low-power circuits, two each for analog circuits, three for digital circuits and four to supply RF circuits. All are designed for high efficiency and software programmability in 50mV steps. The chip also includes a 1W stereo audio amplifier, valuable for many highly mobile applications but increasingly mandatory for handsfree phone operation. In addition, there is a battery-management subsystem that includes a fuel gauge and multistage charger. The latter includes constant-current, constant-voltage, trickle and top-off charging modes, and is compatible with both lithium and nickel battery chemistries. Bypass circuitry permits the device to power the system directly from an external AC adapter.

The device, packaged in QFN-48 packages with either a 0.4mm or 0.5mm lead pitch, lists for about $1.70 each in large volumes.

- Ron Wilson

Electronic Engineering Times

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