PMIC reduces thermal stress in tablet processors

The AS3721 power management IC features a remote-feedback circuit that helps reduce the thermal stress of applications processors in smartphones and tablets. When paired with the AS3729 point-of-load regulators, the two offer a fast response to load transients and are optimized for Tegra applications processors from Nvidia.

The PMIC enables a compact remote feedback path from the processor to the IC’s integrated dc/dc controllers. A patent-pending design features a feedback interface that needs only two wires instead of the four or five wires typically required by other PMICs. The feedback loop maintains the processor within a safe operating voltage even when supplying fast-changing loads. Using an output capacitor of 40 µF and at an output voltage of 1.0 V, the system’s voltage drop during a step up from 0.5 to 5 A in burst mode is 32 mV (typical). The PMIC can combine up to four devices in an eight-phase configuration that supplies a 20-A maximum output. The PMIC features four dc/dc step-down regulators supplying 4-, 2- and 1.5-A; three dc/dc step-down controllers rated for 5, 10 and 20-A, and 12-digital LDOs.