Hybrid LTPS IGZO Gate Driver Circuit Leakage Current

The patent applies different semiconductor material types to different transistor positions within the circuit. Specifically, LTPS transistors are used in positions requiring high on-state current (such as driving transistors), while IGZO transistors are used in positions where low leakage current is critical (such as storage transistors). This local differentiation allows each transistor to be optimized for its specific functional requirement, resolving the contradiction between on-state current and leakage current at the system level.

The patent creates a hybrid circuit architecture that combines two different semiconductor material systems (LTPS and IGZO) within the same display device. This composite approach leverages the complementary strengths of each material: LTPS provides high carrier mobility and on-state current, while IGZO provides low off-state current. The hybrid configuration allows the circuit to achieve both high drive capability and low leakage simultaneously by appropriately assigning transistor types to different circuit nodes.

The patent strategically places IGZO transistors in specific circuit positions where low leakage current is the primary requirement, such as storage transistors that need to maintain charge and switch transistors in off-states. In these local positions, the low off-state current characteristic of IGZO is maximized while the overall circuit performance is maintained through complementary LTPS transistors in positions requiring high drive current.

The hybrid circuit architecture combines IGZO and LTPS transistors to create a system where the weaknesses of IGZO (lower on-state current) are compensated by the strengths of LTPS (higher on-state current). The composite material approach allows the circuit to achieve low leakage current through IGZO transistors while maintaining adequate drive capability through LTPS transistors in critical driving positions.