855 results about "Current compensation" patented technology

The invention relates to the field of dimming and speed regulation related to illumination, motors and electronics, in particular to a motor-driven circuit for dimming or speed regulation control which is suitable for illumination of a silicon-controlled dimmer or adjustment of a silicon-controlled speed regulator and a control method. A detection compensation circuit for maintaining the normal work of the silicon-controlled dimmer consists of a voltage detection circuit, a current detection circuit, a follow current compensation circuit and a power factor compensation circuit; the on-off running state of the silicon-controlled dimmer or speed regulator is detected by a detection method combining output voltage change and current change of the silicon-controlled dimmer or speed regulator;the on-off and trigger running conditions of the silicon-controlled dimmer are provided by adopting a compensation method combining power factor compensation and follow current compensation; a control circuit of a load consists of a datum transformation circuit, an output duty cycle control circuit, an output current control circuit and a drive output circuit and produces a control signal by detecting mains supply AC phase-shedding operation output of the silicon-controlled dimmer or speed regulator; and the output power of the load is controlled by a load output duty cycle and load working current compound control method so as to realize large output power adjustable range of the load and high linearity of the adjusting process.

An RMS-to-DC converter implements the difference-of-squares function by utilizing two identical squaring cells operating in opposition to generate two signals. An error amplifier nulls the difference between the signals. When used in a measurement mode, one of the squaring cells receives the signal to be measured, and the output of the error amplifier, which provides a measure of the RMS value of the input signal, is connected to the input of the second squaring cell, thereby closing the feedback loop around the second squaring cell. When used in a control mode, a set-point signal is applied to the second squaring cell, and the output of the error amplifier is used to control a variable-gain device such as a power amplifier which provides the input to the first squaring cell, thereby closing the feedback loop around the first squaring cell. Accurate square law approximation at microwave frequencies can be achieved by implementing the squaring cells as series-connected three-transistor multi-tanh transconductance cells. By using carefully balanced squaring cells and a well-balanced error amplifier, approximation errors are cancelled and accurate RMS measurement is realized at high frequencies. A feedforward bootstrapping feature uses an op amp to balance the voltages at the common nodes of the transconductance squaring cells and also provides a balanced differential input drive to one of the squaring cells. A base current compensation circuit for providing accurate base compensation current to both of the squaring cells prevents errors due to DC offset voltages.