Power Electronics

Power Management ICs Offer Dynamic Voltage Scaling

National Semiconductor's LP3971 power management unit (PMU) and LM3370 dual-channel, step-down dc-dc converter feature a digital I2C compatible interface that enables design engineers to customize output voltage, switching modes, and other specifications. Both chips include buck regulators that provide more than 90% efficiency over the entire load range. Power consumption is further minimized through a dynamic voltage-scaling feature that modifies the output voltage in real time to match the computing workload and clock frequencies of the corresponding processors.

Available in a 40-pin LLP, the LP3971 PMU integrates three 1600-mA programmable buck converters and six programmable LDOs. The LP3971 accepts a 2.7-V to 5.5-V input and offers output voltages ranging from 0.8 V to 3.3 V for the buck regulators and 1 V to 3.3 V for the LDOs. Additional features of the LP3971 include a backup battery charger, a power-on-reset function,and the ability for the processor to control the enable and disable of the regulators over the I2C-compatible interface.

Packaged in a 16-pin LLP, the LM3370 supplies 600 mA per channel with high efficiency accomplished by automatic switching between PWM and PFM modes. Quiescent current is 16 mA per channel in the PFM mode. The output voltage range is 1 V to 2 V for the first output and 1.8 V to 3.3 V for the second output, which can be programmed in 50 mV and 100 mV steps, respectively. The LM3379 also features a power-on-reset function and independent enables.

Available now, the LP3971 is priced at $4 each and the LM3370 is priced at $2.10 each, both in 1000-unit quantities.

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