Photodetection device

A photodetection device comprising:

• a first sensor circuit that generates a first pulse signal in response to incidence of photons;
• a second sensor circuit that generates a second pulse signal in response to incidence of photons;
• a first counter that counts a count value in synchronization with one of a plurality of signals including the first and second pulse signals, and outputs a first digital signal indicating the count value and a first carry flag indicating whether or not overflow has occurred;
• and
• a second counter that counts a count value in synchronization with one of the first carry flag and the second pulse signal and outputs a second digital signal indicating the count value;
• a first multiplexer that selects one of the first and second pulse signals and outputs a selected signal to the first counter as a first output signal;
• a second multiplexer that selects one of the first carry flag and the second pulse signal and outputs a selected one to the second counter as a second output signal;
• a control circuit that controls the first and second sensor circuits, wherein
• each of the first and second sensor circuits includes an avalanche photodiode, and a recharge transistor that performs recharge to return a cathode potential of the avalanche photodiode to a predetermined potential,
• the first counter counts in synchronization with the first output signal,
• the second counter counts in synchronization with the second output signal,
• the control circuit controls a count interval, which is an interval at which the recharge is performed, to one of a plurality of intervals,
• the first multiplexer selects the first pulse signal in a case where the count interval is a long interval longer than a predetermined interval, and alternately selects the first and second pulse signals in a case where the count interval is a short interval shorter than the predetermined interval, and
• the second multiplexer selects the second pulse signal in a case where the count interval is the long interval, and selects the first carry flag in a case where the count interval is the short interval.

A photodetection device comprising:

• a first sensor circuit that generates a first pulse signal in response to incidence of photons;
• a second sensor circuit that generates a second pulse signal in response to incidence of photons;
• a first counter that counts a count value in synchronization with one of a plurality of signals including the first and second pulse signals, and outputs a first digital signal indicating the count value and a first carry flag indicating whether or not overflow has occurred;
• a second counter that counts a count value in synchronization with one of the first carry flag and the second pulse signal and outputs a second digital signal indicating the count value;
• a first logic gate that outputs a result of a logic operation on the first and second pulse signals as a first operation result;
• a first multiplexer that selects one of a plurality of signals including the first pulse signal and the first operation result and outputs a selected one to the first counter as a first output signal;
• a second multiplexer that selects one of the first carry flag and the second pulse signal and outputs a selected one to the second counter as a second output signal, wherein the first counter counts in synchronization with the first output signal, and the second counter counts in synchronization with the second output signal;
• and
• a control circuit that controls the first and second sensor circuits, wherein
• each of the first and second sensor circuits includes
• an avalanche photodiode, and
• a recharge transistor that performs recharge to return a cathode potential of the avalanche photodiode to a predetermined potential,
• the control circuit controls a count interval, which is an interval at which the recharge is performed, to one of a plurality of intervals,
• the first multiplexer selects the first pulse signal in a case where the count interval is a long interval longer than a predetermined interval, and alternately selects the first and second pulse signals in a case where the count interval is a short interval shorter than the predetermined interval, and
• the second multiplexer selects the second pulse signal in a case where the count interval is the long interval, and selects the first carry flag in a case where the count interval is the short interval.

A photodetection device comprising:

• a first sensor circuit that generates a first pulse signal in response to incidence of photons;
• a second sensor circuit that generates a second pulse signal in response to incidence of photons;
• a first counter that counts a count value in synchronization with one of a plurality of signals including the first and second pulse signals, and outputs a first digital signal indicating the count value and a first carry flag indicating whether or not overflow has occurred;
• a second counter that counts a count value in synchronization with one of the first carry flag and the second pulse signal and outputs a second digital signal indicating the count value;
• a first logic gate that outputs a result of a logic operation on the first and second pulse signals as a first operation result;
• a first multiplexer that selects one of a plurality of signals including the first pulse signal and the first operation result and outputs a selected one to the first counter as a first output signal;
• a second multiplexer that selects one of the first carry flag and the second pulse signal and outputs a selected one to the second counter as a second output signal, wherein the first counter counts in synchronization with the first output signal, and the second counter counts in synchronization with the second output signal;
• and
• a third sensor circuit that generates a third pulse signal in response to incidence of photons;
• a fourth sensor circuit that generates a fourth pulse signal in response to incidence of photons;
• a second logic gate that outputs a result of a logic operation on the third and fourth pulse signals as a second operation result;
• a third logic gate that outputs a result of a logic operation on an output of each of the first and second logic gates as a third operation result;
• a third multiplexer that outputs one of a second carry flag indicating whether or not overflow has occurred, the third pulse signal, and the second operation result as a third output signal;
• a third counter that counts a count value in synchronization with the third output signal and outputs a third digital signal indicating the count value and a third carry flag indicating whether or not overflow has occurred;
• a fourth multiplexer that outputs one of the third carry flag or the fourth pulse signal as a fourth output signal;
• and
• a fourth counter that counts a count value in synchronization with the fourth output signal and outputs a fourth digital signal indicating the count value, wherein
• the first multiplexer selects one of the first pulse signal, the first operation result, and the third operation result, and
• the second counter further generates the second carry flag.

A photodetection device comprising:

• a first sensor circuit that generates a first pulse signal in response to incidence of photons;
• a second sensor circuit that generates a second pulse signal in response to incidence of photons;
• a first counter that counts a count value in synchronization with one of a plurality of signals including the first and second pulse signals, and outputs a first digital signal indicating the count value and a first carry flag indicating whether or not overflow has occurred;
• a second counter that counts a count value in synchronization with one of the first carry flag and the second pulse signal and outputs a second digital signal indicating the count value;
• a first logic gate that outputs a result of a logic operation on the first and second pulse signals as a first operation result;
• a first multiplexer that selects one of a plurality of signals including the first pulse signal and the first operation result and outputs a selected one to the first counter as a first output signal;
• and
• a second multiplexer that selects one of the first carry flag and the second pulse signal and outputs a selected one to the second counter as a second output signal, wherein
• the first counter counts in synchronization with the first output signal, and the second counter counts in synchronization with the second output signal,
• the first multiplexer selects the first pulse signal in a case where a non-addition low illuminance mode in which illuminance does not exceed a predetermined value is set, alternately selects the first pulse signal and the first operation result in a case where a non-addition high illuminance mode in which illuminance is higher than the predetermined value is set, and selects the first operation result in a case where an addition mode is set, and
• the second multiplexer selects the second pulse signal in a case where the non-addition low illuminance mode is set, selects the first carry flag in a case where the non-addition high illuminance mode is set, and selects the first carry flag in a case where the addition mode is set.