Abstract: An illuminating light communication device, which is for establishing a communication system capable of controlling fluctuation in intensity of illuminating light when transmitting data using a power line and illuminating light, and satisfactorily carrying out communication using the power line and communication using the illuminating light, is provided. When data is transmitted through the power line, a signal component is extracted by a filter unit 12, and the demodulated by a power line modulator-demodulator 13, thereby retrieving the data. The retrieved data is temporarily stored in a protocol converter 14. Afterward, the data is converted to the optical communication protocol, and blinking or amount of light of a semiconductor light emitting element 16 is controlled according to the data transmitted from a light source control unit 15, thereby modulating the illuminating light. This allows transmission of data utilizing the illuminating light.

Abstract: The present invention provides a power supply for a semiconductor light emitting device capable of efficiently modulating and driving a current-driven semiconductor light emitting device. An LED 31, a switching element 32, which modulates and drives the LED 31, and an average current detector 12, which detects an average current flowing through the LED 31, are connected to a voltage source 11. When the LED 31 is modulated and driven by the switching element 32, blinking or light quantity of the LED is controlled, and the LED 31 then emits modulated light. The average current detector 12 detects an average light quantity emitted from the LED 31 and then controls the voltage source to output a voltage so that the average current flowing through the LED 31 can be almost constant. As a result, the average light quantity may be kept almost constant with or without modulation of the LED 31.

Abstract: A time division switching circuit with time slot interchange uses an input shift register to convert one-frame binary coded input data of time division multiplex type from an incoming line into a parallel bit output. The parallel bit output undergoes gate control of a gate matrix and its bit array is statically changed to a given bit array. The on/off control of the gate at the cross point of the gate matrix is conducted according to parallel bit outputs of a plurality of control shift registers which stores predetermined contents. The one-frame bit data thus exchanged are supplied to an output shift register. They are transmitted to an outgoing line as binary coded output data of time division multiplex type.