PMIC Solutions

PMIC devices are power management integrated circuits that provide the power circuit solution for products. This category includes: voltage regulators, battery management, and supervisors, LED drivers, motor drivers/controllers and hot swap controllers. Most solutions have a main integrated circuit as the name suggests, but also require additional components for the complete circuit. PMIC devices are available to provide integrated solutions for all power supply rails of many common microprocessors and FPGAs. Voltage regulators are DC-to-DC converters that are available in a number of topologies. Linear regulators are active devices that act like a variable resistor, the resistance dynamically responding to the instantaneous load that is under regulation. They work by sensing the voltage across the load, and adjusting this level compared to a fixed voltage reference that is usually integrated in the device (a bandgap reference). Switching regulators are available to step-down or step-up the voltage from one supply rail to another. They typically have an inverter circuit which switches current on and off into an inductive or capacitive storage element. Switch-mode regulators compare the output voltage level to a reference voltage, and then by controlling the on/off (mark to space) ratio or the switching frequency of the switched waveform, the voltage can be changed to react to a dynamically changing load. They are much more efficient than linear regulators due to the amplifier output being a square wave – the device having very low resistance when fully ON and very low current when fully OFF. Switch-mode regulators are available in buck, boost and buck-boost configurations. Battery management devices are also known as charge controllers. They actively monitor the power supply of a battery and react to provide safety (in fault or overload conditions) and protection against reduction of the life expectancy of the battery by over discharging. Batteries also have sophisticated charging voltage and current requirements relating to the battery chemistry that these devices can control. Battery levels can drop below a critical level where dependent circuitry will fail. Battery managers can include temperature sensing inputs and current sensing capability, and may have sophisticated algorithms to allow for aging and other characteristics of the batteries. Supervisors check the condition of the power supplies and generate controls that react intelligently to changes in the supplies outside their operational expectations. This protects the operation of the system to ensure that over voltage does not kill circuits, and under voltage does not cause spurious operation (for microprocessors this can be called a brown-out). Supervisors can turn supplies ON or OFF or cause power up reset conditions in microprocessor based systems. A simple supervisor can be incorporated into a device called a watchdog timer. When a processor stops working it stops pulsing a timer that detects timeout conditions and resets the system.