The TPS65140/145 offers a compact and small power supply solution to provide all three voltages required by thin film transistor (TFT) LCD displays. The auxiliary linear regulator controller can be used to generate a 3.3-V logic power rail for systems
powered by a 5-V supply rail only.
The main output Vo1 is a 1.6-MHz fixed frequency PWM boost converter providing the source drive voltage for the LCD display. The device is available in two versions with different internal switch current limits to allow the use of a smaller external inductor
when lower output power is required. The TPS65140 has a typical switch current limit of 2.3 A and the TPS65145 has a typical switch current limit of 1.37 A. A fully integrated adjustable charge pump doubler/tripler provides the positive LCD gate drive voltage. An externally adjustable negative charge pump provides the negative gate drive voltage. Due
to the high 1.6-MHz switching frequency of the charge pumps, inexpensive and small 220-nF capacitors can be used.
Additionally, the TPS65140/145 has a system power good output to indicate when all supply rails are acceptable. For LCD panels powered by 5 V, only the TPS65140/145 has a linear regulator controller using an external transistor to provide a regulated 3.3-V
output for the digital circuits. For maximum safety, the entire device goes into shutdown as soon as one of the outputs is out of regulation. The device can be
enabled again by toggling the input or the enable (EN) pin to GND.
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