Renesas Electronics Corporation High-Performance Notebook PWM Controller with Audio-Frequency Clamp ISL6269BCRZ

The ISL6269B IC is a Single-phase Synchronous-Buck PWM controller featuring Intersil's Robust Ripple Regulator R3™ Technology that delivers truly superior dynamic response to input voltage and output load transients. Integrated MOSFET drivers and bootstrap diode result in fewer components and smaller implementation area. Intersil’s R3™ Technology combines the best features of fixed-frequency PWM and hysteretic PWM while eliminating many of their shortcomings. R3™ Technology employs an innovative modulator that synthesizes an AC ripple voltage signal VR, analogous to the output inductor ripple current. The AC signal VR enters a window comparator where the lower threshold is the error amplifier output VCOMP and the upper threshold is a programmable voltage reference VW, resulting in generation of the PWM signal. The voltage reference VW sets the steady-state PWM frequency. Both edges of the PWM can be modulated in response to input voltage transients and output load transients, much faster than conventional fixed-frequency PWM controllers. Unlike a conventional hysteretic converter, the ISL6269B has an error amplifier that provides ±1% voltage regulation at the FB pin. The ISL6269B has a 1.5ms digital soft-start and can be started into a pre-biased output voltage. A resistor divider is used to program the output voltage setpoint. The ISL6269B can be configured to operate in Continuous Conduction Mode (CCM) or Diode Emulation Mode (DEM), which improves light-load efficiency. In CCM the controller always operates as a synchronous rectifier, however when DEM is enabled, the low-side MOSFET is permitted to stay off, blocking negative current flow into the low-side MOSFET from the output inductor.