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MAX17122
19-4951; Rev 1; 11/09
EVAALVU...
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MAX17122
19-4951; Rev 1; 11/09
EVAALVUAAILTAIOBNLEKIT
Step-Up, Step-Down
Regulator, Gate-On Charge Pump, and Boost-Buck
Regulator for TV TFT LCD Display
General Description
The MAX17122 multiple-output power-supply IC generates all the supply rails for thin-film
transistor (TFT) liquidcrystal display (LCD) TV panels. It can operate from 8V to 16.5V input voltages and is optimized for LCD TV panel applications running directly from 12V regulated supplies. It includes a 22V internal-switch step-down
regulator for digital logic, a 22V internal switch stepup
regulator to power the TFT source drivers, and a temperature-compensated 36V internal-switch boostbuck
regulator that produces a negative output that can vary according to the temperature sensed by an external NTC thermistor. All three of these
regulators feature high-efficiency and fixed-frequency operation. Highfrequency operation allows the use of small inductors and capacitors, resulting in a compact solution.
The MAX17122 includes a positive charge-pump linear
regulator controller that uses an external
pnp bipolar junction
transistor (BJT) to typically form a regulated charge-pump doubler to supply the LCD positive gatedriver supply voltage. A negative gate-driver supply is derived linearly between the boost-buck
regulator’s output and ground, using an external
npn BJT connected to ground and a small bypass capacitor.
Other features inclu...