The ISL6308A is a three-phase PWM control IC with integrated MOSFET drivers. It provides accurate voltage regulation systems for a variety of applications, including but not limited to high current low voltage load point converters, embedded applications and other general purpose low voltage media to high current applications. The integration of the power MOSFET driver into the controller IC marks a departure from the separate PWM controller and driver configurations of the previous polyphase product family.
Timing Diagram
Schematic diagram of power system
By reducing the number of external parts, this integration enables a cost - and space-saving power management solution. A unique feature of the ISL6308A is the combination of DCR and rDS(ON) current sensing. Load line voltage positioning and overcurrent protection are realized through continuous inductance DCR current sensing and rDS(ON) current sensing to achieve accurate channel current balance. Both current sampling methods can make full use of the advantages of each technique.
Pinout
The protection function of the controller IC includes a complex set of overvoltage and overcurrent protection. The overvoltage causes the converter to turn the lower MOSFETs on to clamp the rising output voltage and protect the load. An OVP output is also provided to drive an optional pry bar device. The overcurrent protection level is set through a single external resistor. Other protection functions include remote sensing input open circuit protection. Combined, these features provide advanced protection against output loads. The output voltage can be programmed using an on-chip DAC or an external precision reference.
Block Diagram
The two-digit code programs the DAC reference to one of four possible values (0.6V, 0.9V,1.2V, and 1.5V). A unit-gain, differential amplifier provides remote voltage sensing, compensating for any potential difference between remote and local ground. The output voltage can also be offset by using a single external resistor. Also implemented is an optional droop feature that can be disabled for applications that have less stringent output voltage variation requirements or experience less severe stepping loads.
Typical application
