A bidirectional shift register includes a former stage multiplexer, a latter stage multiplexer, a former stage full-swing shift register, and a latter stage full-swing shift register, all of which have a plurality of registers all of the same type. The former and the latter stage multiplexers output signals according to a forward clock, a backward clock, a forward control signal, and a backward control signal. The former and the latter stage full-swing shift register store the signals output from the former and the latter stage full-swing shift registers respectively.
A switch set used in a bi-directional shift register circuit includes a plurality of switch devices. Each switch device is controlled by corresponding control signals to switch the direction of the input signal. One of the switch devices includes a first switch unit for transmitting a shift register signal from a previous shift register to a shift register according to a first control signal, a second switch unit for transmitting a shift register signal from a next shift register to the shift register according to a second control signal. The first and the second control signals have the same frequency as the clock signal of the shift register circuit.
