micro-PMIC provides integrated power management for wearable devices
The AS3701, a micro-PMIC (power management IC) with a low quiescent current, implements multiple power-regulation, power-saving, battery-charging, protection and start-up functions in a chip-scale package (WL-CSP) measuring 2 mm x 2 mm x 0.4 mm.
Power system designers using the AS3701 will be able to realize space savings and provide advanced power management functionality in products supplied by a single lithium-ion cell, such as smart watches, sport bands, wearable medical devices, handheld GPS units and mobile phones.
The AS3701’s multiple power rails include two 200 mA LDOs, a 500mA step-down DC-DC converter and two 40 mA (maximum) programmable current sinks. The synchronous step-down (buck) converter, which switches at high frequencies up to 4 MHz, only requires a small inductor and a 10 µF output capacitor.
The micro-PMIC’s integrated li-ion battery charger can operate in trickle-charge, constant current and constant voltage modes and supplies a maximum charging current of 500 mA. The device’s power path management allows a device to start up with a dead battery, and optimizes power distribution between the battery charging circuit and the system power supply when plugged in to the mains.
Many designs will use the AS3701’s I2C interface to enable configuration by a host processor or microcontroller. But the device also includes multi-purpose I/Os for wake-up/power-down inputs, PWM inputs and outputs, interrupts and control tasks when operating in stand-alone mode.
A one-time programmable (OTP) boot sequence gives designers the flexibility to adapt the micro-PMIC’s start-up operation for different applications and processors. This allows OEMs to use the same power solution in multiple end-product designs, simplifying the development process and consolidating inventory.
Integrated battery temperature monitoring, power-on reset and over-current protection help to ensure reliable and safe operation.
Availability and Pricing
The AS3701 micro-PMIC is available in production volumes. The device is priced at $0.82 each in order quantities of 1,000.
An evaluation board for the AS3701 is available online from ams.