Buck and Synchronous Rectifier Pulse-Width Modulator (PWM) Controller

The ISL6522 provides complete control and protection for a DC-DC converter optimized for high-performance microprocessor applications. It is designed to drive two N-Channel MOSFETs in a synchronous rectified buck topology. The ISL6522 integrates all of the control, output adjustment, monitoring and protection functions into a single package. The output voltage of the converter can be precisely regulated to as low as 0.8V, with a maximum tolerance of ±1% over temperature and line voltage variations. The ISL6522 provides simple, single feedback loop, voltage-mode control with fast transient response. It includes a 200kHz free-running triangle-wave oscillator that is adjustable from below 50kHz to over 1MHz. The error amplifier features a 15MHz gain-bandwidth product and 6V/µs slew rate which enables high converter bandwidth for fast transient performance. The resulting PWM duty ratio ranges from 0-100%. The ISL6522 protects against overcurrent conditions by inhibiting PWM operation. The ISL6522 monitors the current by using the rDS(ON) of the upper MOSFET which eliminates the need for a current sensing resistor.