A motor control device includes a converter that converts AC power into DC power, a smoothing capacitor provided in a DC link, an inverter that converts the DC power in the DC link into AC power for a motor, a capacitor capacity measurement unit that measures a capacity of the smoothing capacitor, a data record unit that records a plurality of pieces of data composed of a measurement value of the capacity of the smoothing capacitor and a date or both a date and time when the measurement has been performed, a deterioration characteristic calculation unit that calculates a deterioration characteristic line indicating a change of the capacity of the smoothing capacitor with respect to elapsed time, on the basis of the recorded data, and a life prediction unit that predicts a period when a life of the smoothing capacitor ends, on the basis of the deterioration characteristic line.

A method for multiphase frequency to voltage conversion includes generating for each cycle of an oscillating input, one of a plurality of non-overlapping clocks. A respective voltage in proportion to an input frequency of the oscillating input, is generated in response to each of the non-overlapping clocks, with a respective one of a plurality of frequency to voltage converters. Each of the respective voltages is summated to generate a voltage sum proportional to the input frequency.

Analog counter circuits, read-out integrated circuits, and infrared detector devices are disclosed. In one embodiment, an analog counter circuit includes a first capacitor including a first terminal and a second terminal, a switch electrically coupled the first capacitor and a first voltage input, a field effect transistor, and a second capacitor. Setting the switch to an on-state pre-charges the first capacitor such that a voltage at the second terminal of the first capacitor is the first voltage. Applying a charge voltage at a charge input further charges the first capacitor. When a voltage at the second terminal of the first capacitor is greater than a threshold voltage of the field effect transistor, the field effect transistor turns on and transfers a charge on the first capacitor to the second capacitor.

A method for multiphase frequency to voltage conversion includes generating for each cycle of an oscillating input, one of a plurality of non-overlapping clocks. A respective voltage in proportion to an input frequency of the oscillating input, is generated in response to each of the non-overlapping clocks, with a respective one of a plurality of frequency to voltage converters. Each of the respective voltages is summated to generate a voltage sum proportional to the input frequency.

A method for multiphase frequency to voltage conversion includes generating for each cycle of an oscillating input, one of a plurality of non-overlapping clocks. A respective voltage in proportion to an input frequency of the oscillating input, is generated in response to each of the non-overlapping clocks, with a respective one of a plurality of frequency to voltage converters. Each of the respective voltages is summated to generate a voltage sum proportional to the input frequency.

A frequency variable oscillator generates a clock having a frequency according to a control signal. A reference current source generates a reference current. A path selector distributes the reference current to a first path and a second path in a time-sharing manner in synchronization with the clock. An F/V conversion circuit includes a capacitor connected to the first path, and charges or discharges the capacitor with the reference current and generates a detection voltage. The reference voltage source includes a resistor connected to the second path, and outputs a reference voltage according to a voltage across the resistor. A feedback circuit adjusts a control signal so that the detection voltage approaches the reference voltage.

A frequency variable oscillator generates a clock having a frequency according to a control signal. A reference current source generates a reference current. A path selector distributes the reference current to a first path and a second path in a time-sharing manner in synchronization with the clock. An F/V conversion circuit includes a capacitor connected to the first path, and charges or discharges the capacitor with the reference current and generates a detection voltage. The reference voltage source includes a resistor connected to the second path, and outputs a reference voltage according to a voltage across the resistor. A feedback circuit adjusts a control signal so that the detection voltage approaches the reference voltage.

A security method for monitoring an optical module and a three-dimensional sensor using the same apply electromagnetic induction to the three-dimensional sensor to monitor the optical module and a light source module. Two inductive coils corresponding to each other are arranged on the light source module and the optical module. An alternative current is inputted to one of the inductive coils and another of the inductive coils generates an inductive current. The value of the inductive current is continuously detected. When the value of the inductive current varies, the abnormality of the optical module is determined to shut down the light source module, thereby completing the security mechanism of the three-dimensional sensor.

A security method for monitoring an optical module and a three-dimensional sensor using the same apply electromagnetic induction to the three-dimensional sensor to monitor the optical module and a light source module. Two inductive coils corresponding to each other are arranged on the light source module and the optical module. An alternative current is inputted to one of the inductive coils and another of the inductive coils generates an inductive current. The value of the inductive current is continuously detected. When the value of the inductive current varies, the abnormality of the optical module is determined to shut down the light source module, thereby completing the security mechanism of the three-dimensional sensor.

A frequency variable oscillator generates a clock having a frequency according to a control signal. A reference current source generates a reference current. A path selector distributes the reference current to a first path and a second path in a time-sharing manner in synchronization with the clock. An F/V conversion circuit includes a capacitor connected to the first path, and charges or discharges the capacitor with the reference current and generates a detection voltage. The reference voltage source includes a resistor connected to the second path, and outputs a reference voltage according to a voltage across the resistor. A feedback circuit adjusts a control signal so that the detection voltage approaches the reference voltage.