The TPS6514x series 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 and TPS65141 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 or 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 TPS6514x series has a system power good output to indicate when all
supply rails are acceptable. For LCD panels powered by 5 V the device 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 TPS65140 and TPS65145 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. The TPS65141 does not enter shutdown when one of its outputs is below its power
good threshold.
