A fast-transient buffer with voltage booting technique for LCD column drivers

A pair of complementary class-A buffers with voltage boosting technique is presented. The driving capabilities of the buffers are improved by adding auxiliary transistors to pull-down/pull-up the gate voltages of the buffer output transistors to induce large current for discharging/charging, respectively. To save power, the auxiliary transistors are turned off in steady state operation. Compared to the previous works, the size of these auxiliary transistors can be significantly reduced when the gate-source voltage boosting is adopted. The measurement results showed that each buffer consumes 3 μA static current under supply voltage of 5V, and its settling times of the rising and falling edges with a capacitance of 600 pF for an input swing of 5 V are 3.5 μs and 1.8 μs. The settling time of the buffer with the proposed technique is faster than that of the buffer without it by about 2 times. Hence, the proposed output buffers realize fast response and maintain low power consumption.