PMICs: Features and Benefits

The sequences of our PMICs are flexibly configurable by using one-time-programmable memory (OTP). An OTP is a kind of read-only memory which allows data to be registered only once. After data registration, the OTP becomes read-only. Here, in the premise of using an OTP to set a start-up sequence and default voltages, we will show you one example of a power-supply start-up timing chart and default values of each power supply.

Default voltages and start-up sequences are programmable with an OTP. These default settings can be changed by I2C access from the processor to the register. Also, you can select the interval of delay steps from 0.5 ms or 2 ms with an OTP. The steps cannot be changed with a register.

Sequence control is a function to control the power-on/off sequences at a system's starting up or turning to a sleep mode. The power-on order toward functional blocks inside an SoC is determined in advance, and a PMIC must control the power supplies to power the SoC according to the power-on order. This is one of the major purposes of sequence control. It prevents bus contention by powering on/off at a proper timing. Also, each power supply in a PMIC has various functions as a soft-start function and an inrush current prevention, and if all the power supplies turn on at the same time, the PMIC may malfunction due to its input voltage drop. Sequence control is also helpful to prevent malfunction by decentralizing the power-on timing of each power supply and by dispersing inrush current.

Selectable Functions of GPIOs