Bandgap reference circuit using heterogeneous power and electronic device having the same

An image sensor comprising:

• a pixel array configured to generate an image signal;
• a bandgap reference circuit configured to
• receive an analog ground and a digital ground the analog ground received through a first path separate from the digital ground, and the digital ground received through a second path separate from the analog ground,
• generate a reference voltage based on the analog ground and the digital ground, and
• generate a reference current based on the reference voltage;
• a ramp generator configured to generate a ramp voltage based on the reference current;
• a comparator configured to generate a comparison signal based on a comparison operation of the image signal and the ramp voltage;
• a counter configured to determine a count value based on the comparison signal;
• and
• a driver and decoder configured to control the pixel array based on the reference voltage.