A semiconductor device with reduced power consumption and a display device including the semiconductor are provided. The semiconductor device generates a bias voltage that is to be supplied to a buffer amplifier. When the display device displays a still image, a data signal for updating the image need not be supplied from the buffer amplifier to a pixel array in the next frame; therefore, the circuit is configured so that the buffer amplifier is brought into a standby state (temporarily stopped). Specifically, input of a reference current from a BGR circuit to the semiconductor is stopped and a bias voltage is applied from the semiconductor device to the buffer amplifier to temporarily stop the operation of the buffer amplifier.