Signal processing circuit, image scanner, and image forming apparatus

An image scanner configured to operate in at least a first mode and a second mode consuming relatively less power than the first mode, the image scanner comprising:

• a timing controller including,
• a reference clock generator configured to constantly generate a reference clock signal when the image scanner is operating in any of the first mode or the second mode,
• a plurality of first signal generators configured to generate, based on the reference clock, first control signals only if the image scanner is operating in the first mode,
• a plurality of second signal generators configured to generate, based on the reference clock, second control signals if the image scanner is operating in any one of the first mode and the second mode, and
• a mode selector to select and shift an operating mode of the image scanner between the first mode and the second mode;
• a photoelectric converter configured to photoelectrically convert light reflected from a document image to an image signal;
• a driving unit configured to drive the photoelectric converter based on one of the first control signals;
• an analog processing unit configured to conduct direct current recovery of the image signal received from the photoelectric converter and to convert the received image signal to digital image data based on one of the first control signals generated only if the image scanner is operating in the first mode;
• and
• a data transmitter configured to receive the digital image data from the analog processing unit and to transmit the digital image data, a line synchronization signal and a differential clock signal to an image processing unit based on at least one of the second control signals such that the image processing unit receives and processes the line synchronization signal and a differential clock signal irrespective of whether the image scanner is operating in the first mode or the second mode.