Triple-rail bias for LTPS LCD panels
The Texas Instruments TPS65111RGER is a charge pump IC designed to generate the three bias voltages required by low-temperature polysilicon (LTPS) LCD panels: -3V, 5V, and 9V. It accepts a 2.4V to 5.5V input, making it suitable for battery-powered or USB-supplied portable displays. The three outputs are generated from a single charge pump architecture, eliminating the need for multiple discrete converters.
Output voltages and load budgeting
The three output rails (-3V, 5V, 9V) are the key selection parameters. The 9V rail typically supplies the gate-on bias for the LTPS TFT array; the 5V rail powers the source driver and logic; the -3V rail provides the gate-off bias to prevent leakage. The charge pump's output current capability is shared across the three rails — the total load must stay within the device's power budget, which is not explicitly stated in the brief but is a common constraint in charge-pump-based bias generators. The input range from 2.4V to 5.5V covers single-cell Li-ion (3.0V-4.2V typical) and 5V USB supplies. At the low end (2.4V), the charge pump must work harder to generate the 9V output, so the available output current will be lower than at higher input voltages. Designs running near the minimum input should budget for reduced load capability.
The 24-VFQFN Exposed Pad package (4x4 mm body, 24-VQFN supplier package) is a compact, thermally enhanced QFN. The exposed pad helps keep the junction temperature within limits under full load at the high end of the range.
The TPS65111RGER is officially marked as Obsolete by Texas Instruments. This means TI no longer manufactures the device, and no last-time-buy window is open. New designs should not use this part. For existing BOM lines, the only sourcing path is through independent distributors and surplus brokers who hold remaining inventory. Availability is limited to what is already in the channel — no new production will be built. Because the part is obsolete, there is no official successor from TI that is pin-compatible and function-identical. Any replacement will require a board redesign. The closest functional replacement would be a newer charge pump or DC-DC converter that can generate the same three output rails, but the pinout and control logic will differ.