Display drive circuit and method, LED display board and display device

The display drive circuit includes: an interface circuit for acquiring a plurality of grayscale data and a plurality of current gain data; a command processing circuit electrically coupled with the interface circuit; a cache circuit electrically coupled with the interface circuit and configured for caching the plurality of grayscale data and the plurality of current gain data; a current source circuit electrically coupled with the command processing circuit and including a plurality of channel current sources; a channel grayscale control circuit, electrically coupled with the command processing circuit, the cache circuit and the current source circuit, and configured for respectively controlling duration of turning on of the plurality of channel current sources according to the plurality of grayscale data; and a channel current control circuit electrically coupled with the cache circuit and the current source circuit, and configured for respectively controlling output currents of the plurality of channel current sources.