ISL97522

Description

The ISL97522 represents a 4-channel supply control IC for use in large panel TFT-LCD displays. Supporting inputs from 4.5V to 13V, the ISL97522 includes a boost controller to achieve the required AVDD output voltage. Both VON and VOFF are generated using off-chip charge-pumps which are then post regulated using on-board LDO controllers. The logic supply is generated using an internal nonsynchronous buck controller. This controller runs at 180 out of phase with the AVDD supply to minimize input noise. The AVDD, VOFF, and VON outputs are automatically sequenced as AVDD, VOFF, and VON. By using an optional external series transistor with AVDD (Q1), the start-up sequence can be adjusted to VOFF, AVDD and then VON. A VON slicing circuit is also included to reduce LCD flicker. The ISL97522 also incorporates a fault protection circuit that can disable the IC and turn off all outputs when an output short is detected. (Note that to protect AVDD a single external transistor is required).