EUP2681
TFT LCD DC-DC Converter with Integrated
Charge Pumps, OP-AMP and HV-Switch
DESCRIPTION
The EUP2681 generates power supply rails for thin-film
transistor (TFT) liquid-crystal display (LCD) panels in
monitors and notebooks operated from 2.5V to 5.5V input
supply. The device integrates a step-up converter, positive
and negative charge pumps, a high speed V
COM
buffer and a
HV-Switch.
The external compensated step-up converter features an
internal power MOSFET and high frequency operation
allowing to use small inductors and capacitors. The step up
converter uses fixed-frequency peak current mode control
architecture which provides fast load-transient response and
easy compensation. A 3.5A peak current limit for the
internal switch protects power supply fault condition.
The regulated positive and negative charge pump regulators
generate the positive and negative supply rails for the TFT
LCD gate resistive voltage-divider ICs.
The high speed V
COM
buffer features 500mA short circuit
current, 20MHz bandwidth, fast slew rate 45V/µs, and
rail-to-rail inputs and outputs.
The HV-Switch circuit control provides the ability to
control the slope for the gate drive voltage. It shapes the
TFT gate high voltage to improve image quality.
The EUP2681 is available in a small (4mm× 4mm) 24 pin
TQFN package and operates over the -40ºC to +85ºC
temperature range.
FEATURES
2.5V to 5.5V Input Supply Range
1.2MHz Current Mode Step Up Converter
- Built-In 20V, 3.5A, 0.16Ω N-MOSFET
- High Efficiency Up to 90%
- Internal digital Soft-Start
- Fast Transient Response to Pulsed Load
- Over-Temperature Protection
Regulated Charge pump for TFT gate-on Supply
Regulated Charge pump for TFT gate-off Supply
High Speed High Current 18V V
COM
Buffer
- 20MHz BW
- 45V/µS Slew Rate
- More than 500mA Peak Output Current
HV-Switch Circuit
- Adjustable Falling rate
- Reduction of Coupling Effect between Gate Line
and Pixel
- Flicker Compensation Circuit
Input Under Voltage Lockout and Thermal Protection
24 pin 4mm×4mm TQFN Package
RoHS Compliant and 100% Lead (Pb)-Free
Halogen-Free
APPLICATIONS
LCD Monitors
Notebook Display
LCD TVs
DS2681
Ver1.0
Nov. 2009
1
EUTECH [ EUTECH MICROELECTRONICS INC ]
