A new power management IC (PMIC) has been released by ams with a remote-feedback circuit. This helps reduce the thermal stress of applications processors in smartphones and tablets.
When used with the company’s new AS3729 point-of-load regulators, the new AS3721 PMIC is claimed to provide a complete power management system that offers fast response to load transients.
The two new devices are designed for use with Tegra applications processors from Nvidia.
The company advises its new PMIC enables a compact remote feedback path from the processor to the IC’s integrated DC-DC controllers. The feedback interface to the PMIC 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 point-of-load power stages, the two devices can be placed far apart in the board layouts of space-constrained devices such as smartphones, tablets and notebooks. This is claimed to be able to significantly reduce 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 feedback loop carried over thePMIC’s two-wire interface also operates extremely fast, maintaining the processor it supports within its safe operating voltage even when supplying extremely fast-changing loads. Using an output capacitor of 40µF and at an output voltage of 1.0V, the system’s voltage drop during a step up from 0.5A to 5A in burst mode is 32mV (typical).
The point-of-load regulators contain NMOS and PMOS FETs for each of two phases, which can be controlled separately and can handle an output current of 2.5A.
The PMIC features four DC-DC step-down regulators supplying 4A, 2A and 1.5A; three DC-DC step-down controllers rated for 5A, 10A and 20A; 12 digital LDOs; a real-time clock; a supervisor circuit; GPIOs; a general-purpose ADC; and a one-time programmable boot sequence. The device’s 8mm by 8mm BGA package has a pitch of 0.5mm.
ams
