TFT LCD gate driver circuit with two-transistion output level shifter

A drive circuit for a liquid crystal display panel comprising:

• a current source providing a reference voltage;
• and
• a plurality of circuits for converting voltage levels for the liquid crystal display panel, each of the circuits further comprising:
• a signal including a first state of a first voltage level and a second state of a second voltage level;
• a first power supply providing the first voltage level;
• a first transistor including a gate electrode coupled to the first power supply, a first electrode receiving the signal, and a second electrode coupled to a node;
• a second power supply providing a third voltage level;
• and
• a second transistor including a gate electrode biased at the reference voltage, a first electrode coupled to the second power supply and a second electrode coupled to the node;
• wherein a voltage level at the node is pulled to approximately the third voltage level in response to the first state of the signal, and pulled to approximately the second voltage level in response to the second state of the signal.

A circuit for converting voltage levels for a liquid crystal display panel comprising:

• a first power supply providing a first voltage level;
• a second power supply providing a second voltage level;
• a third power supply providing a third voltage level;
• a first transistor including an electrode coupled to the first power supply;
• a second transistor including an electrode coupled to the second power supply;
• a third transistor including an electrode coupled to the third power supply;
• a first input signal including a first state and a second state;
• a second input signal including a first state and a second state;
• an output signal;
• a first unit turning on and turning off the first transistor respectively in response to the first and second states of the first input signal;
• a second unit turning on and turning off the second transistor respectively in response to the first and second states of the second input signal;
• a decoder decoding the first and second input signals and providing a decoded signal including a first state and a second state;
• and
• a third unit turning on and turning off the third transistor respectively in response to the first and second states of the decoded signal.

A method of converting voltage levels for a liquid crystal display panel comprising:

• providing a current source providing a reference voltage;
• providing a signal including a first state of a first voltage level and a second state of a second voltage level;
• providing a first power supply providing the first voltage level;
• providing a first transistor including a gate electrode coupled to the first power supply, a first electrode receiving the signal, and a second electrode coupled to a node;
• providing a second power supply providing a third voltage level;
• providing a second transistor including a gate electrode biased at the reference voltage, a first electrode coupled to the second power supply and a second electrode coupled to the node;
• pulling a voltage level at the node to approximately the third voltage level in response to the first state of the signal;
• and
• pulling a voltage level at the node to approximately the second voltage level in response to the second state of the signal.

A method of converting voltage levels for a liquid crystal display panel comprising:

• providing a first power supply to provide a first voltage level;
• providing a second power supply to provide a second voltage level;
• providing a third power supply to provide a third voltage level;
• providing a first transistor including an electrode coupled to the first power supply;
• providing a second transistor including an electrode coupled to the second power supply;
• providing a third transistor including an electrode coupled to the third power supply;
• providing a first input signal including a first state and a second state;
• providing a second input signal including a first state and a second state;
• providing an output signal;
• providing a first unit to turn on and turn off the first transistor respectively in response to the first and second states of the first input signal;
• providing a second unit to turn on and turn off the second transistor respectively in response to the first and second states of the second input signal;
• providing a decoder to decode the first and second input signals and provide a decoded signal including a first state and a second state;
• and
• providing a third unit to turn on and turn off the third transistor respectively in response to the first and second states of the decoded signal.