Digital-to-analog conversion circuit, operating method thereof, and solid-state imaging device including the same

A digital-analog conversion (DAC) circuit comprising:

• a current source cell;
• a current-voltage conversion circuit configured to convert a signal variation of an output current of the current source cell into a first output voltage;
• a first voltage divider circuit configured to divide the first output voltage of the current-voltage conversion circuit at a first ratio and output a second output voltage;
• and
• a first amplifier circuit configured to amplify the second output voltage of the first voltage divider circuit, generate a first ramp signal based on the second output voltage amplified by the first amplifier circuit, and output the first ramp signal to an analog-digital conversion (ADC) circuit.

An operating method of a digital-analog conversion (DAC) circuit for supplying a ramp signal to an analog-digital conversion (ADC) circuit, the operating method comprising:

• converting, by a current-voltage conversion circuit of the DAC circuit, a signal variation of an output current from a current source cell into a first voltage;
• dividing, by a voltage divider circuit of the DAC circuit, the first voltage to generate a second voltage;
• and
• amplifying, by an amplifier circuit of the DAC circuit, the second voltage through buffer driving to generate a ramp signal.