Photoelectric conversion apparatus, photoelectric conversion system, and moving body
According to an aspect of the present disclosure, an avalanche diode, a detection unit configured to detect an avalanche current generated by avalanche multiplication in the avalanche diode, a switch disposed between the avalanche diode and the detection unit, and a reset unit configured to reset a node between the switch and the detection unit. The reset unit resets the node during a period in which the switch is in an off state.
1. A photoelectric conversion apparatus comprising:
an avalanche diode;
a detection circuit configured to output a signal based on an avalanche current generated by avalanche multiplication in the avalanche diode;
a counter configured to count the number of generation times of the avalanche current detected by the detection circuit;
a switch disposed between an output node of the avalanche diode and the counter;
a reset circuit configured to reset a node between the switch and the detection circuit; and
a second reset circuit configured to reset the output node of the avalanche diode,
wherein a transistor constituting the switch and a transistor constituting the reset circuit have opposite conductivity types,
wherein a gate of the reset circuit is not connected to an output node of the detection circuit,
wherein the reset circuit resets the node during a period in which the switch is in an off state, and
wherein a response time of the second reset circuit is longer than Td, where Td represents an interval between a falling edge and a rising edge of a potential input to the detection circuit when a threshold voltage of the detection circuit is passed through.
2. The photoelectric conversion apparatus according to claim 1 ,
wherein the detection circuit is an inverter,
wherein an output node of the inverter is connected to a second inverter, and
wherein an output node of the second inverter is connected to each of the switch and the reset circuit.
3. The photoelectric conversion apparatus according to claim 1 ,
wherein the reset circuit is connected to an output node of the avalanche diode via the switch, and
wherein the reset circuit functions as a quench element during a period in which the switch is in an on state.
4. The photoelectric conversion apparatus according to claim 1 , wherein turning on and off of the switch is controlled by a clock pulse to be periodically input.
5. The photoelectric conversion apparatus according to claim 4 , wherein the reset circuit resets the node in response to input of the clock pulse.
6. The photoelectric conversion apparatus according to claim 5 , wherein the clock pulse is simultaneously input to the switch and the reset circuit.
7. The photoelectric conversion apparatus according to claim 5 , wherein the reset circuit is turned on after the switch is turned off, and the switch is turned on after the reset circuit is turned off.
8. The photoelectric conversion apparatus according to claim 5 , wherein the clock pulse has a frequency of 1/Td, where Td represents an interval between a falling edge and a rising edge of a potential input to the detection circuit when a threshold voltage of the detection circuit is passed through.
9. The photoelectric conversion apparatus according to claim 5 , wherein the reset circuit resets the node in a case where a period in which a potential of the output node of the avalanche diode exceeds a threshold for the detection circuit exceeds a predetermined time.
10. The photoelectric conversion apparatus according to claim 1 ,
wherein the switch is disposed between the second reset circuit and the detection circuit.
11. The photoelectric conversion apparatus according to claim 1 ,
wherein a plurality of photoelectric conversion circuits each including the avalanche diode, the detection circuit, and the switch is two-dimensionally arranged, and
wherein the plurality of photoelectric conversion circuits is configured to individually control turning on and off of each of the reset circuit and the switch.
12. The photoelectric conversion apparatus according to claim 1 , further comprising a first substrate and a second substrate stacked on the first substrate,
wherein the first substrate includes the detection circuit, and
wherein the second substrate includes the avalanche diode.
13. A photoelectric conversion system comprising:
a photoelectric conversion apparatus according to claim 1 ; and
a signal processing circuit configured to process a signal output from the photoelectric conversion apparatus.
14. A moving body comprising:
a photoelectric conversion apparatus according to claim 1 ; and
a distance information acquisition circuit configured to acquire distance information from parallax information based on a signal output from the photoelectric conversion apparatus, the distance information indicating a distance from an object,
wherein the moving body further comprises a control circuit configured to control the moving body based on the distance information.