Περιγραφή
The ISL6232 is a high efficiency, quad output controller optimized for converting battery, wall adapter or network DC input voltage into system supply voltages required for portable applications. The ISL6232 includes two PWM controllers generating 0.8V to 5.5V, or fixed 5V and 3.3V outputs. It also features 5V and 3.3V always linear regulators with up to 100mA output current. ISL6232 uses constant frequency current mode PWM control with out-of-phase operation for reducing the input ripple current and the ESR requirement of the input capacitors. Over 95% efficiency is achieved through synchronous rectification and dual PWM/Skip mode architecture. High light load efficiency with skip mode extends the battery life in system standby or shutdown mode. The 5V and 3.3V always linear regulators take their inputs from battery or AC-adapter; and, to further improve efficiency, their outputs are switched to the 5V or 3.3V outputs from switching regulators when 5V or 3.3V is available. Ultrasonic pulse skipping mode maintains switching frequency above 25kHz to eliminate the audio noise for high light load efficiency, and fixed frequency PWM operation mode reduces the RF interference in sensitive applications. External loop compensation is used to optimize the transient response with optimized external components. An accurate current sensing resistor in series with an output inductor, or DC resistance of the inductor is used to sense the output current of the current ramp signal, and overcurrent protection. A peak current detecting scheme is used for overcurrent protection and to prevent the inductor from saturation. The ISL6232 has internal soft-start to control the inrush current. The soft-stop feature avoids negative output voltage for undervoltage protection, overcurrent protection, and shutdown by discharging output through an internal switch, and by damping the inductor current. The ISL6232 also features overvoltage protection, power-up sequences, power good output, and thermal shutdown. It has quiescent power dissipation as low as 3.5mW.
