A successive approximation register (SAR) analog-to-digital converter (ADC) comprises a comparator for generating a comparison value according to an analog signal; a SAR, coupled to the comparator, comprises N memory units, each memory unit storing a control value and the N control values being related to the comparison value, N being an integer greater than two; and a thermometer-coded DAC, which generates the analog signal and is coupled to the comparator and the SAR. The thermometer-coded DAC comprises N capacitors. The N capacitors are respectively coupled to the N memory units. The N terminal voltages of the N capacitors are respectively controlled by the N control values.

A successive approximation register (SAR) analog-to-digital converter (ADC) comprises a comparator for generating a comparison value according to an analog signal; a SAR, coupled to the comparator, comprises N memory units, each memory unit storing a control value and the N control values being related to the comparison value, N being an integer greater than two; and a thermometer-coded DAC, which generates the analog signal and is coupled to the comparator and the SAR. The thermometer-coded DAC comprises N capacitors. The N capacitors are respectively coupled to the N memory units. The N terminal voltages of the N capacitors are respectively controlled by the N control values.

A high resolution analog to digital converter (ADC) with improved bandwidth senses an analog signal (e.g., a load current) to generate a digital signal. The ADC operates based on a load voltage produced based on charging of an element (e.g., a capacitor) by a load current and a digital to analog converter (DAC) output current (e.g., from a N-bit DAC). The ADC generates a digital output signal representative of a difference between the load voltage and a reference voltage. This digital output signal is used directly, or after digital signal processing, to operate an N-bit DAC to generate a DAC output current that tracks the load current. In addition, quantization noise is subtracted from the digital output signal thereby extending the operational bandwidth of the ADC. In certain examples, the operational bandwidth of the ADC extends up to 100s of kHz (e.g., 200-300 kHz), or even higher.

A high resolution analog to digital converter (ADC) with improved bandwidth senses an analog signal (e.g., a load current) to generate a digital signal. The ADC operates based on a load voltage produced based on charging of an element (e.g., a capacitor) by a load current and a digital to analog converter (DAC) output current (e.g., from a N-bit DAC). The ADC generates a digital output signal representative of a difference between the load voltage and a reference voltage. This digital output signal is used directly, or after digital signal processing, to operate an N-bit DAC to generate a DAC output current that tracks the load current. In addition, quantization noise is subtracted from the digital output signal thereby extending the operational bandwidth of the ADC. In certain examples, the operational bandwidth of the ADC extends up to 100s of kHz (e.g., 200-300 kHz), or even higher.

A solid state imaging device includes a pixel circuit 102 configured to generate a pixel signal by photoelectric conversion, a reference signal generation circuit 115 configured to generate a reference signal which changes in level with time, and a plurality of comparators configured to, based on the reference signal generated by the reference signal generation circuit, compare a plurality of reference signals being given offset voltages differing from each other, with the pixel signal, or compare a plurality of pixel signals being given offset voltages differing from each other, with the reference signal.

A solid state imaging device includes a pixel circuit 102 configured to generate a pixel signal by photoelectric conversion, a reference signal generation circuit 115 configured to generate a reference signal which changes in level with time, and a plurality of comparators configured to, based on the reference signal generated by the reference signal generation circuit, compare a plurality of reference signals being given offset voltages differing from each other, with the pixel signal, or compare a plurality of pixel signals being given offset voltages differing from each other, with the reference signal.

The present invention discloses an analog-to-digital conversion circuit having speed-up comparison mechanism. Each of a positive and a negative capacitor arrays receives a positive and a negative input voltages to generate a positive and a negative output voltages. A first comparator performs comparison thereon to generate a first comparison result and a second comparator performs comparison according to a reference voltage to generate a second comparison result. A control circuit switches a capacitor enabling combination of the capacitor arrays according to the first comparison result and outputs a digital code as a digital output signal when the positive and the negative output voltages equal. The control circuit operates in a speed-up switching mode when a difference between the positive and the negative output voltages is outside of a predetermined range defined by the reference voltage and operates in a normal switching mode when the difference is within the predetermined range.

The present invention discloses an analog-to-digital conversion circuit having speed-up comparison mechanism. Each of a positive and a negative capacitor arrays receives a positive and a negative input voltages to generate a positive and a negative output voltages. A first comparator performs comparison thereon to generate a first comparison result and a second comparator performs comparison according to a reference voltage to generate a second comparison result. A control circuit switches a capacitor enabling combination of the capacitor arrays according to the first comparison result and outputs a digital code as a digital output signal when the positive and the negative output voltages equal. The control circuit operates in a speed-up switching mode when a difference between the positive and the negative output voltages is outside of a predetermined range defined by the reference voltage and operates in a normal switching mode when the difference is within the predetermined range.

The present invention discloses an analog-to-digital conversion circuit having quick tracking mechanism is provided. A positive and a negative capacitor arrays receive a positive and a negative input voltages and output a positive and a negative output voltages. A first and a second comparators performs comparison thereon respectively according to and not according to a reference voltage to generate a first and a second comparison results. A control circuit does not perform level-shifting when a difference between the positive and the negative output voltages is not within a predetermined range. The control circuit assigns the positive and the negative capacitor arrays a voltage up-tracking direction and a voltage down-tracking direction respectively to switch a capacitor enabling combination with digital codes according to the second comparison result, and outputs the digital codes as a digital output signal when the positive and the negative output voltages equal.

The present invention discloses an analog-to-digital conversion circuit having quick tracking mechanism is provided. A positive and a negative capacitor arrays receive a positive and a negative input voltages and output a positive and a negative output voltages. A first and a second comparators performs comparison thereon respectively according to and not according to a reference voltage to generate a first and a second comparison results. A control circuit does not perform level-shifting when a difference between the positive and the negative output voltages is not within a predetermined range. The control circuit assigns the positive and the negative capacitor arrays a voltage up-tracking direction and a voltage down-tracking direction respectively to switch a capacitor enabling combination with digital codes according to the second comparison result, and outputs the digital codes as a digital output signal when the positive and the negative output voltages equal.