Photodetection device and photodetection system
A photodetection device according to the present disclosure includes: a plurality of light-receiving sections that each includes a light-receiving element, and generates a first pulse signal including a pulse corresponding to a result of light reception by the light-receiving element; an adder that generates a second pulse signal by selecting one or more first pulse signals from a plurality of the first pulse signals generated by the plurality of light-receiving sections and performing addition processing on the basis of the one or more selected first pulse signals; a divider that performs division processing for dividing the second pulse signal into a plurality of third pulse signals in a time division manner on the basis of a clock signal; a plurality of counters that is provided corresponding to the plurality of third pulse signals, and each performs count processing on the basis of a corresponding one of the third pulse signals; and a controller that sets signal number of the one or more pulse signals to be subjected to the addition processing on the basis of respective count values of the plurality of counters.
1 . A photodetection device comprising:
a plurality of light-receiving sections that each includes a light-receiving element, and generates a first pulse signal including a pulse corresponding to a result of light reception by the light-receiving element;
an adder that generates a second pulse signal by selecting one or more first pulse signals from a plurality of first pulse signals generated by the plurality of light-receiving sections and performing addition processing on a basis of the one or more selected first pulse signals;
a divider that performs division processing for dividing the second pulse signal into a plurality of third pulse signals in a time division manner on a basis of a clock signal;
a plurality of counters that is provided corresponding to the plurality of third pulse signals, and each performs count processing on a basis of a corresponding one of the plurality of third pulse signals; and
a controller that sets a signal number of the one or more first pulse signals to be subjected to the addition processing on a basis of respective count values of the plurality of counters.
2 . The photodetection device according to claim 1 , wherein
the controller determines light intensity on a basis of the respective count values of the plurality of counters,
in a case where the light intensity is first light intensity, the controller sets the signal number to a first number, and
in a case where the light intensity is second light intensity that is lower than the first light intensity, the controller sets the signal number to a second number that is larger than the first number.
3 . The photodetection device according to claim 2 , wherein the controller determines the light intensity on a basis of whether or not a total count value of a plurality of count values of the plurality of counters reaches a predetermined count value.
4 . The photodetection device according to claim 2 , wherein the controller determines the light intensity on a basis of whether or not one or more of a plurality of count values of the plurality of counters reach a predetermined count value.
5 . The photodetection device according to claim 1 , wherein
the photodetection device has a first operation mode and a second operation mode, and
in the first operation mode, the adder generates the second pulse signal by performing the addition processing, and each of the plurality of counters performs the count processing on the basis of the corresponding one of the plurality of third pulse signals.
6 . The photodetection device according to claim 5 , wherein
a number of the plurality of counters is the same as a number of the plurality of light-receiving sections,
the plurality of counters correspond one by one to the plurality of first pulse signals, and
in the second operation mode, each of the plurality of counters performs the count processing on a basis of a corresponding one of the plurality of first pulse signals.
7 . The photodetection device according to claim 6 , wherein the controller sets the signal number on a basis of the respective count values of the plurality of counters in the second operation mode.
8 . The photodetection device according to claim 5 , wherein
a number of the plurality of counters is different from a number of the plurality of light-receiving sections,
the plurality of counters is reconfigured into two or more counters that are same in number as the plurality of light-receiving sections,
the two or more counters correspond one by one to the plurality of first pulse signals, and
in the second operation mode, each of the two or more counters performs the count processing on a basis of a corresponding one of the plurality of first pulse signals.
9 . The photodetection device according to claim 8 , wherein the controller sets the signal number on a basis of respective count values of the two or more counters in the second operation mode.
10 . The photodetection device according to claim 5 , wherein
the light-receiving element is provided in a first path between a first node and a first power supply node, and
each of the plurality of light-receiving sections includes
a load element provided in a second path between the first node and a second power supply node,
a variable resistor provided between the first node and the light-receiving element in the first path, and
a generator that generates the first pulse signal on a basis of a voltage at the first node.
11 . The photodetection device according to claim 10 , wherein
the variable resistor is configured to set a resistance value to a first resistance value or a second resistance value that is larger than the first resistance value,
in the first operation mode, the variable resistor sets the resistance value to the first resistance value, and
in the second operation mode, the variable resistor sets the resistance value to the second resistance value.
12 . The photodetection device according to claim 1 , wherein
each of the plurality of light-receiving sections includes
a transistor having a gate coupled to the light-receiving element, a source, and a drain,
a first switch that supplies a first power supply voltage to the source of the transistor by being turned on,
a second switch that supplies a second power supply voltage to the drain of the transistor by being turned on, and
a control circuit that turns on one of the first switch and the second switch and turns off another one of the first switch and the second switch after a lapse of a predetermined time from change in a voltage at the drain, on a basis of the voltage at the drain of the transistor.
13 . The photodetection device according to claim 1 , wherein the light-receiving element includes an avalanche photodiode.
14 . The photodetection device according to claim 1 , wherein the light-receiving element includes a single photon avalanche diode.
15 . The photodetection device according to claim 1 , wherein
a plurality of photodetection units is provided, and
each of the plurality of photodetection units includes the plurality of light-receiving sections, the adder, the divider, the plurality of counters, and the controller.
16 . The photodetection device according to claim 1 , wherein
a plurality of light-receiving elements is provided on a first semiconductor substrate, and
the adder, the divider, and the plurality of counters are provided on a second semiconductor substrate bonded to the first semiconductor substrate.
17 . A photodetection system, comprising:
a light-emitting section that emits light; and
a photodetector that detects light reflected by a detection object of the light emitted from the light-emitting section, wherein
the photodetector includes
a plurality of light-receiving sections that each includes a light-receiving element, and generates a first pulse signal including a pulse corresponding to a result of light reception by the light-receiving element,
an adder that generates a second pulse signal by selecting one or more first pulse signals from a plurality of first pulse signals generated by the plurality of light-receiving sections and performing addition processing on a basis of the one or more selected first pulse signals,
a divider that performs division processing for dividing the second pulse signal into a plurality of third pulse signals in a time division manner on a basis of a clock signal,
a plurality of counters that is provided corresponding to the plurality of third pulse signals, and each performs count processing on a basis of a corresponding one of the third pulse signals, and
a controller that sets a signal number of the one or more first pulse signals to be subjected to the addition processing on a basis of respective count values of the plurality of counters.