DETECTION DEVICE OF POWER-SUPPLY TROUBLE OR OTHER TROUBLES IN DIGITAL CIRCUIT

摘要

PURPOSE: To allow the detector to select a standby mode by detecting a fault of a power supply or a digital circuit without addition of components or any specially designed circuit. CONSTITUTION: A television receiver includes a standby power supply ST and operating power supplies U2, X2, and a microprocessor 30 connecting to the standby power supply controls changeover between the operating mode and the standby mode. The microprocessor 30 makes digital communication with a tuner 50 through a 2-way data bus 40. The microprocessor 30 calls periodically the tuner 50 to monitor data on the data bus 40. When the tuner 50 fails to response or responses inadequately, the microprocessor 30 selects the standby mode to deenergize the operating power supplies. When data in a memory 34 do not indicate the changeover into the standby recently or repetitively automatically, the microprocessor 30 selects the operating mode again according to an instruction.