| High-definition, high resolution, low power, low voltage make the TFT-LCD (Thin-Film Transistor Liquid Crystal Display) have very bright future. And as the power supply system of the TFT-LCD becomes more and more integrated, the area, cost, efficiency, stability and transient response of the power supply will become the bottleneck which limits the speed of the whole system improved and degrades the performance of TFT-LCD. Since above reasons, this paper mainly focuses on the research of loop-stability, control mode and dimension of integrated low cost multi-output power supply scheme for TFT-LCD .The theory and method for improving the display quality are also proposed in the paper.The system structure of the single chip integrated power supply which includes Boost DC/DC, Buck DC/DC, multi-mode low ripple charge pump with active regulation, low quiescent current LDO, high performance OP (operational amplifier), gate pulse modulate controller (GPM) is proposed, which increases the integration of the power supply system, makes the size of the power system smaller and saves cost. The production of the research in this paper is as follow:1. A piecewise linear slope compensation circuit providing a compensation signal whose slope varies with different duty cycles is designed, which reduces the negative effect of slope compensation on the system's load capacity and transient response.2. In order to save the cost and area of the TFT-LCD supply system, a novel drive circuit suitable for Buck DC/DC converters is proposed which is consisted of charge pump and adaptive dead time control logic. The proposed drive circuit makes the efficiency of the power system increase greatly.3. In order to make the power supply satisfy the requirement of the digital logic drive circuit of TFT-LCD, a novel low quiescent current LDO with dual active compensation structure is proposed. It can produce two system zeros varying with load current to cancel the negative effect of pole at different load on the system's stability. No current consuming makes the power consumption of the system lower.4. Adjustable output and multiple modes charge pump with low ripple voltage is used as the power supply system of the gate drive circuit of TFT-LCD, which decreases the EMI of the system and improves the display quality of TFT-LCD. Since the working mode is decided by the load, the power consumption is reduced.5. A novel method for verification of the charge pump is proposed. For the voltage loop, the power MOSFET of adjustable charge pump is modeled as a voltage controlled current source and pump capacitance is replaced by a voltage source, which can make the system model linearized. And the verification of the system can be obtained according to the Bode plot from the simulation.6. To prevent occurrence of flicker phenomenon on a liquid crystal, a gate pulse modulate controller(GPM) is designed.The logic circuit for adjustable output delay and adjustable falling slope is induced which reduces the flicker phenomenon caused by the parasitic capacitance for routing of the gate drive wire of TFT-LCD and improves the display quality of TFT-LCD.7. To avoid the occurrence of flick phenomenon caused by voltage chopping for bounce and parasatice capacitance, a high performance operational amplifier (OP) is design to drive the common electrode of TFT-LCD. The proposed OP can increase the transient response speed for the slew rate enchance circuit added and guarantee the safety of the system for the short current limit circuit added.
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