A system and method with AC coupling that reserves photodiode bandwidth in a biased configuration, allows optimal transimpedance amplifier performance, retains DC signal measurement capability, and does not introduce noise into the balanced detection signal.

A system and method with AC coupling that reserves photodiode bandwidth in a biased configuration, allows optimal transimpedance amplifier performance, retains DC signal measurement capability, and does not introduce noise into the balanced detection signal.

An optical measurement apparatus having an improved light intensity detection performance is provided. The optical measurement apparatus includes a light receiving element capable of converting a light intensity of light to be analyzed into an electrical signal; an input terminal to which the electrical signal is input; a first amplifier and a nonlinear element configuring a logarithmic amplifier; offset resistors; a switch unit; and a controller. An inverting input terminal of the first amplifier is electrically connected to the input terminal. The offset resistors have different resistance values. The switch unit can switch an offset resistor electrically connected between the voltage source and the input terminal, of the offset resistors. An offset current is input to the input terminal by the offset resistor electrically connected between the voltage source and the input terminal. The controller measures the light intensity based on an output voltage value of the first amplifier.

An optical measurement apparatus having an improved light intensity detection performance is provided. The optical measurement apparatus includes a light receiving element capable of converting a light intensity of light to be analyzed into an electrical signal; an input terminal to which the electrical signal is input; a first amplifier and a nonlinear element configuring a logarithmic amplifier; offset resistors; a switch unit; and a controller. An inverting input terminal of the first amplifier is electrically connected to the input terminal. The offset resistors have different resistance values. The switch unit can switch an offset resistor electrically connected between the voltage source and the input terminal, of the offset resistors. An offset current is input to the input terminal by the offset resistor electrically connected between the voltage source and the input terminal. The controller measures the light intensity based on an output voltage value of the first amplifier.

An ambient light sensor is provided that includes a sensor input having a delta-sigma analogue to digital converter. The delta-sigma analogue to digital converter includes a switched capacitor, a common mode voltage source, a reference voltage source, and a switch network. In a first clock phase, the switch network connects the switched capacitor to charge it to either a sum or difference voltage. In a second clock phase, the switch network connects the switched capacitor to transfer charge into a summing junction. A controller controls the switch network in response to a comparator output to connect the switched capacitor to either the common mode voltage or the reference voltage while in the first clock phase.

An ambient light sensor is provided that includes a sensor input having a delta-sigma analogue to digital converter. The delta-sigma analogue to digital converter includes a switched capacitor, a common mode voltage source, a reference voltage source, and a switch network. In a first clock phase, the switch network connects the switched capacitor to charge it to either a sum or difference voltage. In a second clock phase, the switch network connects the switched capacitor to transfer charge into a summing junction. A controller controls the switch network in response to a comparator output to connect the switched capacitor to either the common mode voltage or the reference voltage while in the first clock phase.

Provided are a light intensity detection circuit, a light intensity detection method and an light intensity detection apparatus. The light intensity detection circuit includes a photoelectric conversion sub-circuit, a source follower sub-circuit, a reset sub-circuit, a read sub-circuit and a sense sub-circuit. The photoelectric conversion sub-circuit generates a corresponding electrical signal according to an incident light signal, and outputs it to a first node; the source follower sub-circuit generates a corresponding voltage signal or current signal according to the electrical signal of the first node and outputs it to a second node; the read sub-circuit reads the voltage signal or current signal of the second node to determine an incident light intensity; the reset sub-circuit provides a voltage at a offset voltage terminal to the first node.

Provided are a light intensity detection circuit, a light intensity detection method and an light intensity detection apparatus. The light intensity detection circuit includes a photoelectric conversion sub-circuit, a source follower sub-circuit, a reset sub-circuit, a read sub-circuit and a sense sub-circuit. The photoelectric conversion sub-circuit generates a corresponding electrical signal according to an incident light signal, and outputs it to a first node; the source follower sub-circuit generates a corresponding voltage signal or current signal according to the electrical signal of the first node and outputs it to a second node; the read sub-circuit reads the voltage signal or current signal of the second node to determine an incident light intensity; the reset sub-circuit provides a voltage at a offset voltage terminal to the first node.

A welding helmet can record a welding time based on an arc intensity detected by a sensor mounted on the helmet. A configured level is compared with the arc intensity detected by the sensor to determine a welding duration. Individual welding times from multiple welding instances can be accumulated over a period of time to provide a total welding time for an operator. The total welding time may be stored in the welding helmet.

A welding helmet can record a welding time based on an arc intensity detected by a sensor mounted on the helmet. A configured level is compared with the arc intensity detected by the sensor to determine a welding duration. Individual welding times from multiple welding instances can be accumulated over a period of time to provide a total welding time for an operator. The total welding time may be stored in the welding helmet.