US 2021/0199501 A1Published application

Dynamic time gain controlling light sensing device comprising a dynamic time gain adjustment module to control a plurality of gain selection switches

AssigneeAnpec Electronics Corporation

InventorsCHIH-NING CHEN, CHIH-HENG SU

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Abstract

A dynamical time gain controlling light sensing device generates a detection time configuration signal according to a light intensity indication signal, and generates a set of adjustment switch signals to respectively control the plurality of gain selection switches to be turned on or off according to a ratio of a real gain time and a simulation gain time within a detection time, such that an overall gain of a resolution adjustment circuit can correspond to an substitute gain lower than a set gain within the simulation gain time and correspond to the set gain within the real gain time, thereby generating an adjusted count result signal.

Claims10

Dependent claims

A dynamic time gain controlling light sensing device, comprising:

a light sensor having a first terminal and a second terminal, wherein the second terminal of the light sensor is coupled to a ground terminal;
a first transistor connected between a first voltage and the light sensor;
a second transistor connected between the first voltage and a voltage storage node, and forming a first current mirror with the first transistor to mirror a photocurrent generated when the light sensor detects light being incident;
a resolution adjustment circuit including a plurality of gain transistors respectively connected to the first voltage and connected to the voltage storage node through a plurality of gain selection switches, respectively, wherein the gain transistors respectively form a plurality of current mirrors with the first transistor, and the plurality of current mirrors respectively mirror the photocurrent with a plurality of gains different from each other;
a storage capacitor connected between the voltage storage node and a ground terminal;
a comparator having a first input connected to the voltage storage node and a second input connected to a reference voltage, wherein the comparator is configured to output a triggered signal when a voltage of the voltage storage node exceeds the reference voltage;
a delay reset unit configured to delay the triggered signal by a predetermined delay time to generate a reset switch signal;
a reset switch connected between the voltage storage node and the ground terminal, and having a control terminal controlled by the reset switch signal to reset the voltage of the voltage storage node;
a counter configured to count the triggered signal to generate a count value and correspondingly generate a count result signal;
and
a dynamic time gain adjustment module, including:
a time and gain control register configured to generate a set of initial switching signals according to a set gain to control the gain selection switches to be turned on or off respectively, thereby controlling an overall gain of the resolution adjustment circuit to correspond to the set gain;
a light intensity detection module configured to receive the count result signal generated under the set gain to determine whether a current light intensity indicates a strong light state or a weak light state according to the count value, and correspondingly generate a light intensity indication signal;
and
an arithmetic operation module configured to generate a detection time configuration signal according to the light intensity indication signal, wherein the detection time configuration signal is used to indicate a proportional configuration of a real gain time and a simulation gain time within a detection time, and the proportional configuration is stored in a register,
wherein the time and gain control register is configured to generate a set of adjustment switch signals according to the proportional configuration to control the gain selection switches to be turned on or off, such that the overall gain of the resolution adjustment circuit corresponds to a substitute gain that is lower than the set gain within the simulation gain time, and corresponds to the set gain within the real gain time;
and
wherein the counter is configured to count the triggered signal to generate a first adjusted count value and correspondingly generate an adjusted count result signal, wherein the adjusted count result signal is used to indicate an adjusted light intensity result.

15 more elements

Dependencies are inferred from the claim text.

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Abstract

A dynamic time gain controlling light sensing device, comprising:

a light sensor having a first terminal and a second terminal, wherein the second terminal of the light sensor is coupled to a ground terminal;
a first transistor connected between a first voltage and the light sensor;
a second transistor connected between the first voltage and a voltage storage node, and forming a first current mirror with the first transistor to mirror a photocurrent generated when the light sensor detects light being incident;
a resolution adjustment circuit including a plurality of gain transistors respectively connected to the first voltage and connected to the voltage storage node through a plurality of gain selection switches, respectively, wherein the gain transistors respectively form a plurality of current mirrors with the first transistor, and the plurality of current mirrors respectively mirror the photocurrent with a plurality of gains different from each other;
a storage capacitor connected between the voltage storage node and a ground terminal;
a comparator having a first input connected to the voltage storage node and a second input connected to a reference voltage, wherein the comparator is configured to output a triggered signal when a voltage of the voltage storage node exceeds the reference voltage;
a delay reset unit configured to delay the triggered signal by a predetermined delay time to generate a reset switch signal;
a reset switch connected between the voltage storage node and the ground terminal, and having a control terminal controlled by the reset switch signal to reset the voltage of the voltage storage node;
a counter configured to count the triggered signal to generate a count value and correspondingly generate a count result signal;
and
a dynamic time gain adjustment module, including:
a time and gain control register configured to generate a set of initial switching signals according to a set gain to control the gain selection switches to be turned on or off respectively, thereby controlling an overall gain of the resolution adjustment circuit to correspond to the set gain;
a light intensity detection module configured to receive the count result signal generated under the set gain to determine whether a current light intensity indicates a strong light state or a weak light state according to the count value, and correspondingly generate a light intensity indication signal;
and
an arithmetic operation module configured to generate a detection time configuration signal according to the light intensity indication signal, wherein the detection time configuration signal is used to indicate a proportional configuration of a real gain time and a simulation gain time within a detection time, and the proportional configuration is stored in a register,
wherein the time and gain control register is configured to generate a set of adjustment switch signals according to the proportional configuration to control the gain selection switches to be turned on or off, such that the overall gain of the resolution adjustment circuit corresponds to a substitute gain that is lower than the set gain within the simulation gain time, and corresponds to the set gain within the real gain time;
and
wherein the counter is configured to count the triggered signal to generate a first adjusted count value and correspondingly generate an adjusted count result signal, wherein the adjusted count result signal is used to indicate an adjusted light intensity result.

15 more elements