Power management unit with configurable start up sequences

The PMIC is suitable for portable navigation devices, portable media players, e-dictionaries, GPS devices, PDAs and a range of battery powered handheld devices using ARM based processors. The output voltage and the timing of all regulators of the AS3607 are programmed via software. With the software and demo board, the OTP memory of the AS3607 can be programmed enabling fast prototype runs for quick market introduction. The slope of the ramp can be set for the step down converters. The user can programme the start up sequence with timing steps of 1 or 4ms, ensuring that all ARM based processors can be covered. In order to control other parts of the system, the general purpose I/O pins can be programmed to a specific timing. Manfred Kogler, marketing manager consumer and communications at austriamicrosystems, said: "Last minute changes, slight modifications or even new features are no problem for the AS3607, because it is easy to modify the start up sequence, timing and configuration of regulators. There is no need to redesign the power management portion or to reapprove a new PMIC, which saves time and money. Even if the designer decides to switch to another processor, the PMIC can stay the same. All the software and layout can be completely reused and the AS3607 can be easily programmed to the processor's requirements." In portable systems, the PMIC together with the application processor manage and optimise the power rails within the system to maximise battery charge. According to Kogler, the AS3607 PMIC has a significant space benefit over a discrete solution, since it integrates all the regulators, charger, backlight driver and monitoring functions in a 6x6 mm QFN package. The AS3607 fully programmable power management unit includes: three DC-DC step down converters and five low noise LDO regulators suitable for rf applications, an led backlight driver, two programmable current sinks and a Li-Ion battery charger. The three step down converters deliver 700 mA each with an efficiency of up to 95%, while the fixed 2MHz switching frequency minimises pcb footprint by allowing the use of tiny, low profile inductors. The AS3607 contains a Li-Ion battery charger with constant current and constant voltage with a maximum charging current of 1 A, enabling fast charging of large batteries. An integrated battery switch separates the battery when charging or whenever an external power supply is present. This enables operation of mobile devices with deeply discharged batteries or even with no battery. In order to be compliant to the USB standard the maximum current can be programmed.