Latch and drive method thereof, source drive circuit and display device

A source drive circuit, comprising:

• at least two cascaded first shift register units and at least two latches, an output terminal of each of the first shift register units connected to a first control signal terminal of corresponding latch;
• wherein the latch comprises:
• a first latch circuit connected to a first control signal terminal, a data signal terminal and a transmission node, the first latch circuit configured to, under control of a first pulse control signal from the first control signal terminal, latch a data signal from the data signal terminal at a first latch node and transmit the data signal to the transmission node;
• and
• a second latch circuit connected to the transmission node, a first switch signal terminal, and an output node, the second latch circuit configured to, under control of a first switch signal from the first switch signal terminal, latch a data signal from the transmission node at a second latch node and output the data signal to the output node;
• wherein a loop in the second latch circuit is turned off in response to the data signal written to the second latch node;
• the second latch circuit is further connected to a second switch signal terminal;
• the second latch circuit comprises:
• a second switch sub-circuit connected to the first switch signal terminal, the transmission node and the second latch node, the second switch sub-circuit configured to, under control of the first switch signal, transmit the data signal from the transmission node to the second latch node;
• and
• a second latch sub-circuit connected to the second switch signal terminal, the second latch node and the output node, the second latch sub-circuit configured to, under control of a second switch signal from the second switch signal terminal, latch the data signal at the second latch node and transmit the data signal to the output node.