Abstract: A soft-start circuit includes a power source, a switch, a capacitor and a regeneration brake circuit. The regeneration brake circuit absorbs a return current. The regeneration brake circuit includes a resistor, a diode and a transistor. The resistor is connected between two poles of the power source via the transistor. The diode is connected between the resistor and the positive pole of the power source via the switch. The capacitor is connected between the negative pole of the diode and the transistor. The switch is connected between the negative pole of the diode and resistor. When the switch turns off, the power charges the capacitor via the resistor and the diode of the regeneration brake circuit. When the switch turns on, the return current turns the transistor on, and the resistor absorbs the return current.

Abstract: A current conversion circuit includes a control circuit, and a switch circuit. The control circuit includes a first photoelectric coupler receiving a first driving signal and outputting a first control signal, and a second photoelectric coupler receiving a second driving signal and outputting a second control signal. The switch circuit includes a first transistor and a second transistor connected in series between a positive power source and a negative power source. The first transistor includes a control terminal receiving the first control signal, and the second transistor includes a control terminal receiving the second control signal. A node between the first and second transistors outputs an alternating signal.

Abstract: A soft-start circuit includes a power source, a switch, a capacitor and a regeneration brake circuit. The regeneration brake circuit absorbs a return current. The regeneration brake circuit includes a resistor, a diode and a transistor. The resistor is connected between two poles of the power source via the transistor. The diode is connected between the resistor and the positive pole of the power source via the switch. The capacitor is connected between the negative pole of the diode and the transistor. The switch is connected between the negative pole of the diode and resistor. When the switch turns off, the power charges the capacitor via the resistor and the diode of the regeneration brake circuit. When the switch turns on, the return current turns the transistor on, and the resistor absorbs the return current.

Abstract: A parameter setting device includes a microprocessor, a command port, a display unit, an input unit, and a memory unit. The microprocessor electrically connects to the command port, the display unit, the input unit, and the memory unit.