NSC50198

NSC50198 is a high-performance boost charge pump and inverter capable of generating two output voltages, comprising a pump controller, a positive output voltage, and a negative output voltage. The positive charge pump controller provides an adjustable output AVDD and a fixed -1x ratio AVEE to supply TFT panels. The charge pump clock can be generated by an internal circuit to reduce control signals from the driver IC, or the charge pump state can be synchronized with the LCD TE signal (PSYNC) to minimize display quality interference during state transitions. The device requires only five (12-pin) or seven (16-pin) small, low-cost ceramic capacitors. The NSC50198 is available in a TDFN-12 package, designed for smartphone LCD panel driver ICs. The NSC50198 can provide a suitable and stable voltage level for TFT LCD driver ICs, and can reference the PSYNC signal to switch from charge state to pump state, and vice versa. If the driver IC or ground state cannot provide a PSYNC signal, the PSYNC pin can be connected to GND to enable free-running mode (internal frequency = 125KHz). The difference between free-running mode and synchronous mode is that display quality may be lower in free-running mode, while synchronous mode requires larger stabilizing capacitors to reduce ripple noise; in synchronous mode, since noise is generated during the display blanking interval, it will not be observed on the panel. The NSC50198 positive voltage output AVDD can reach up to 2x the VCI voltage, and can also provide a fixed pump ratio to generate AVEE, with the ratio fixed at -1.0x of AVDD.

Key features

• Input supply voltage range: 2.5V~4.8V
• Control signal voltage range: 1.65V~4.8V
• NSC50198 output voltage range (V_va = 3V, Ivcr = 24mA)
• AVDD output voltage range: 4.8V~6V
• AVEE output voltage range: -4.8V~-6V
• Charge pump clock synchronized with PSYNC for low noise
• Diode-less positive/negative regulated charge pump
• External capacitor limited to 5C or 7C
• Package type: TDFN-12