Photodetector circuit device and method thereof
First Claim
1. A circuit comprising:
- a CMOS compatible photodetector to produce charge in response to incident light;
a plurality of storage nodes to store charge generated by said photodetector;
a plurality of control transistors to route charge from said photodetector to said plurality of storage nodes; and
a plurality of amplifiers coupled to said storage nodes, said plurality of amplifiers to provide an output related to an amount of charge stored in said storage nodes; and
a plurality of reset transistors coupled to said storage node, said plurality of reset transistors to precharge said storage nodes.
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Accused Products
Abstract
A distance measuring device and photosensor circuit are disclosed herein. By pulsing a light source such as an LED to illuminate an object and measuring the phase difference between the light reflected from the object and the original phase of the light source, the distance to an object may be determined. In order to measure the phase difference, a CMOS photosensor or photosensor array may be used to receive the reflected light and store charge generated during different portions of time in different storage nodes or pixel cells. The difference between the amount of charge stored in different storage nodes can be used to determine the phase difference between the original light illuminating the object and the light reflected from the object. This phase difference can in turn be used to determine the distance to the object.
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Citations
27 Claims
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1. A circuit comprising:
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a CMOS compatible photodetector to produce charge in response to incident light;
a plurality of storage nodes to store charge generated by said photodetector;
a plurality of control transistors to route charge from said photodetector to said plurality of storage nodes; and
a plurality of amplifiers coupled to said storage nodes, said plurality of amplifiers to provide an output related to an amount of charge stored in said storage nodes; and
a plurality of reset transistors coupled to said storage node, said plurality of reset transistors to precharge said storage nodes.
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2. A circuit comprising:
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a CMOS compatible photodetector to produce charge in response to incident light;
a plurality of storage nodes to store charge generated by said photodetector;
a plurality of control transistors to route charge from said photodetector to said plurality of storage nodes, wherein said plurality of control transistors include a first transfer transistor to route charge in response to a clock signal in-phase with a reference signal and a second transfer transistor to route charge in response to a clock signal out-of-phase with the reference signal; and
a plurality of amplifiers coupled to said storage nodes, said plurality of amplifiers to provide an output related to an amount of charge stored in said storage nodes. - View Dependent Claims (3, 4, 5, 6, 7, 8)
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9. A circuit comprising:
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a CMOS compatible photodetector to produce charge in response to incident light;
a plurality of storage nodes to store charge generated by said photodetector;
a plurality of control transistors to route charge from said photodetector to said plurality of storage nodes;
a first reset transistor, said first reset transistor including;
a control node to be coupled to a first control signal;
a second current electrode to be coupled to a voltage supply; and
a first current electrode coupled to a first floating node;
a first buffer transistor, said first buffer transistor including;
a control node coupled to said first floating node;
a second current electrode to be coupled to said voltage supply; and
a first current electrode coupled to a current electrode of an output transistor;
said plurality of control transistors including a first transfer transistor, said first transfer transistor including;
a control node to be coupled to a second control signal;
a second current electrode coupled to said first floating node; and
a first current electrode coupled to a charge well of the photodetector;
a second reset transistor, said second reset transistor including;
a control node to be coupled to a third control signal;
a second current electrode to be coupled to a voltage supply; and
a first current electrode coupled to a second floating node;
a second buffer transistor, said second buffer transistor including;
a control node coupled to said second floating node;
a second current electrode to be coupled to said voltage supply; and
a first current electrode coupled to a current electrode of a second output transistor;
said plurality of control transistors further including a second transfer transistor, said second transfer transistor including;
a control node to be coupled to a fourth control signal;
a second current electrode coupled to said second floating node; and
a first current electrode coupled to said charge well of said photodetector;
wherein said photodetector includes the charge well coupled to said first current electrode of said first transfer transistor and further coupled to said first current electrode of said second transfer transistor. - View Dependent Claims (10, 11, 12)
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13. A distance-measuring device comprising:
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a light source;
a clock generator coupled to said light source; and
a photosensor, said photosensor including;
a CMOS compatible photodetector to produce charge in response to incident light;
a plurality of storage nodes to store charge generated by said photodetector;
a plurality of output transistors to couple said storage nodes to an output of said photodetector, said plurality of output transistors includes a plurality of amplifiers coupled to said storage nodes, said plurality of amplifiers to provide an output related to an amount of charge stored in said storage nodes;
a plurality of control transistors to selectively couple said photodetector to said storage nodes; and
a plurality of reset transistors coupled to said storage nodes, said plurality of reset transistors to precharge said storage nodes.
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14. A distance-measuring device comprising:
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a light source;
a clock generator coupled to said light source; and
a photosensor, said photosensor including;
a CMOS compatible photodetector to produce charge in response to incident light;
a plurality of storage nodes to store charge generated by said photodetector;
a plurality of output transistors to couple said storage nodes to an output of said photodetector, said plurality of output transistors includes a plurality of amplifiers coupled to said storage nodes, said plurality of amplifiers to provide an output related to an amount of charge stored in said storage nodes;
a plurality of control transistors to selectively couple said photodetector to said storage nodes, wherein said plurality of control transistors include a first transfer transistor to route charge in response to a clock signal in-phase with a reference signal and a second transfer transistor to route charge in response to a clock signal out-of-phase with the reference signal. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A method comprising:
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generating a reference clock;
pulsing a light source in synchronization with the reference clock;
illuminating a scene with the pulsing light source;
receiving light reflected from an object within the scene using a CMOS photosensor over a predetermined period of time; and
wherein receiving includes;
applying a clock in-phase with the reference clock to a first gate during a first portion of the predetermined period, such that charge generated by a photodetector is stored in a first storage node;
applying a clock out-of-phase with the reference clock to a second gate during a second portion of the predetermined period, such that charge generated by the photodetector is stored in a second storage node; and
determining a distance to the object based on an amount of charge stored in the first storage node and an amount of charge stored in the second storage node. - View Dependent Claims (24, 25)
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26. A method comprising:
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generating a reference clock having a first frequency during a first portion of a phase detection cycle and having a second frequency, different from the first frequency, during a second portion of the phase detection cycle;
pulsing a light source in synchronization with the reference clock during the first portion of the phase detection cycle;
illuminating a scene with the pulsing light source;
receiving light reflected from an object within the scene using a CMOS photosensor over a first predetermined period of time, wherein receiving includes;
applying a clock in-phase with the reference clock to a first gate during a first portion of the first predetermined period, such that charge generated by a photodetector is stored in a first storage node;
applying a clock out-of-phase with the reference clock to a second gate during a second portion of the first predetermined period, such that charge generated by the photodetector is stored in a second storage node;
determining a first phase difference based on an amount of charge stored in the first storage node and an amount of charge stored in the second storage node;
pulsing the light source in synchronization with the reference clock during the second portion of the phase detection cycle;
illuminating the scene with the pulsing light source;
receiving light reflected from the object within the scene using the CMOS photosensor over a second predetermined period of time, wherein receiving includes;
applying a clock in-phase with the reference clock to the first gate during a first portion of the second predetermined period, wherein charge generated by the CMOS photosensor is stored the first storage node;
applying a clock out-of-phase with the reference clock to a second gate during a second portion of the second predetermined period, wherein charge generated by the photodetector is stored in the second storage node;
determining a second phase difference based on an amount of charge stored in the first storage node and an amount of charge stored in the second storage node; and
determining a distance to the object based on the first phase difference and the second phase difference. - View Dependent Claims (27)
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Specification