A current reference circuit includes a reference current supply unit configured to generate a reference current having a target current level, a current-frequency converter configured to receive a first temporary reference current corresponding to the reference current from the reference current supply unit and to generate a first comparison clock signal in response to the first temporary reference current, and a first current compensation unit configured to generate a first current compensation signal used for the first temporary reference current to reach the target current level in response to a frequency of a reference clock signal and a frequency of the first comparison clock signal.

A pre-driver circuit is provided. The pre-driver circuit includes a switch circuit, a common-mode voltage control circuit, and a current supply circuit. The switch circuit receives differential input signals, outputs differential output signals, and controls switching between a high level and a low level of the differential output signals and the differential input signals. The common-mode voltage control circuit is coupled to the switch circuit. The common-mode voltage control circuit receives a reference voltage and controls a common-mode voltage of the differential output signals according to the reference voltage. The current supply circuit is coupled to the switch circuit and the common-mode voltage control circuit. The current supply circuit provides a driving current for the switch circuit and the common-mode voltage control circuit.

A pre-driver circuit is provided. The pre-driver circuit includes a switch circuit, a common-mode voltage control circuit, and a current supply circuit. The switch circuit receives differential input signals, outputs differential output signals, and controls switching between a high level and a low level of the differential output signals and the differential input signals. The common-mode voltage control circuit is coupled to the switch circuit. The common-mode voltage control circuit receives a reference voltage and controls a common-mode voltage of the differential output signals according to the reference voltage. The current supply circuit is coupled to the switch circuit and the common-mode voltage control circuit. The current supply circuit provides a driving current for the switch circuit and the common-mode voltage control circuit.

Provided is an apparatus for controlling an orbiting satellite by sensing a change in a yaw angle of the orbiting satellite and calculating a ground sample distance (GSD) based on the yaw angle. The apparatus may include a sensor configured to sense a yaw angle corresponding to yaw steering of the orbiting satellite, and a processor configured to calculate, based on the yaw angle, a GSD corresponding to a length of a pixel projected onto a planetary surface scanned by the orbiting satellite.

A switching rectifier circuit includes a pulse width modulation controller, a voltage switching circuit, a pulse width modulation comparator, an error amplifier, a voltage reference, a high threshold voltage comparator and a low threshold voltage comparator. A varying output voltage of the voltage regulator is sampled and compared to a high threshold voltage reference and a low threshold voltage reference. When the sampled output voltage is equal to or greater than the high threshold voltage reference the output voltage is decreased. When the sampled output voltage is equal to or less than the low threshold voltage reference the output voltage is increased.