Abstract: A driving device includes an output terminal to output a first control signal, and input terminals configured to be connected respectively with a corresponding terminal of light emitting elements driven by a voltage generated based on the first control signal. A constant-current driver is connected to each of the input terminals, and a control portion is configured to generate a pulse signal based on a signal which is input from the input terminals. An open detection portion is connected with each of the input terminals and configured to determine a connection state of the light emitting elements based on a signal that is input into the input terminals. A current set terminal is configured to be connected to a first resistor, and an over voltage protection circuit is configured to be coupled to a potential between a second resistor and a third resistor.

Abstract: An impedance matched circuit board utilizes a series of vias, one signal via that is surrounded by four ground vias in order to effect impedance matching with a coaxial signal transmission line. The vias are plated and extend through the thickness of the circuit board. Both opposing surfaces of the circuit board are provided with a conductive ground layer and each such ground layer has an opening formed there that encompasses one or more of the vias. On the top surface the opening surrounds the signal and ground via and on the bottom surface the opening only partially surrounds the signal via and the opening includes a convex portion formed therein.

Abstract: An impedance matched circuit board utilizes a series of vias, one signal via that is surrounded by four ground vias in order to effect impedance matching with a coaxial signal transmission line. The vias are plated and extend through the thickness of the circuit board. Both opposing surfaces of the circuit board are provided with a conductive ground layer and each such ground layer has an opening formed there that encompasses one or more of the vias. On the top surface the opening surrounds the signal and ground via and on the bottom surface the opening only partially surrounds the signal via and the opening includes a convex portion formed therein.