ams expands PMIC family for mobile multi-core ARM processors
ams has also released the AS3728, an 8 A high-voltage power stage to complement the AS3722’s high-current DC-DC controllers. The AS3728 provides for a streamlined power architecture in embedded systems, since it can supply the high current required by processor cores directly from a 12 V power rail. The AS3722 PMIC and multiple AS3728 devices power the Tegra K1 processor in Nvidia’s Jetson TK1 reference design board. The Tegra K1, Nvidia’s latest mobile SoC, features a quad-core ARM Cortex-A15 CPU and 192 CUDA graphics processing cores.
Together, the AS3722 and the AS3728 power stage provide a space-saving and thermally efficient power solution for advanced multi-core ARM processors which makes the devices ideal for use in compact mobile devices such as tablets and notebooks, and in industrial applications such as security cameras and fanless (sealed housing) computers, in which the system designer must carefully manage the temperature of circuit boards carrying multiple high-power components. This is because the AS3722 enables a board layout optimized for thermal performance. The feedback interface to the AS3722 only requires two wires (one control signal, one temperature signal) instead of the four or five wires typically required by other PMICs.
With fewer traces connecting the PMIC to the processor, the two devices can be placed far apart in the board layouts of space-constrained devices which reduces the size and intensity of the hotspot around the processor compared to conventional power architectures in which the processor and PMIC, both handling high currents simultaneously, must be located side-by-side.
The AS3722 also helps reduce board space requirements, integrating all the power rails required by a sophisticated processor such as the Tegra K1. The AS3722 includes four step-down DC-DC regulators operating at up to 4 MHz, three step-down DC-DC controllers, 11 universal LDOs, a real-time clock with a 1 µA total current requirement, and a control interface accessed via an I2C or serial peripheral interface.
The AS3728 power stage has a thermally efficient design and supports two phases, each of 4 A (maximum), with an independent control input for each. The device incorporates separate low- and high-side N-channel MOSFETs for each phase.
The AS3722’s three DC-DC controllers may each control the two phases of an AS3728, to provide a maximum 24 A power output. The 3 MHz switching frequency of the DC-DC controllers provides for a fast response to load transients and keeps the size of the external components to a minimum.
The DC-DC controllers also implement automatic phase selection, ensuring that the circuit switches between single- and multiple-phase modes depending on the output current, to optimize energy efficiency while maintaining instant full-load capability when required in the event of a load transient.
The AS3722 is housed in a 124-pin CTBGA package (8 mm x 8 mm x 0.5 mm) or a 108-pin CSP (4.8 mm x 3.6 mm x 0.4 mm). The AS3728 is housed in a 2.4 mm x 1.6 mm x 0.4 mm package which can be assembled on a standard 4 mil PCB without the need for vias.
Availability and Pricing
Both the AS3722 PMIC and the AS3728 power stage are available for volume production today. The AS3722 is priced at $4.12 each in 1,000-unit quantities. The AS3728 is $0.54. An evaluation kit, the AS3722-CT-00_EK_ST AS3728, is available online from ams.
www.ams.com/Power-Management-Units/AS3722
www.ams.com/Power-Management-Units/AS3728
If you enjoyed this article, you will like the following ones: don't miss them by subscribing to :
