| 摘要 |
PURPOSE: A circuit for separating a power unit of a TV phone is provided to separate power of a general circuit unit from power of a caller ID circuit, and to transmit output data of the caller ID circuit to a CPU through a photo coupler, thereby removing a noise problem. CONSTITUTION: An EMI(Electromagnetic Interference) filter(21) prevents an EMI. A rectifier and filter portion(22) rectifies/filters an output voltage of the EMI filter(21). A switching circuit(23) switches the output voltage at a predetermined frequency, and drives a transformer(24). Rectifier and filter portions(25,26) rectify/filter the output voltage, and output a driving voltage and a DC voltage from a caller ID data converter. A main controller(27) controls the switching circuit(23) in PWM method. An excessive power protector(28) prevents an excessive power. A power separator(29) performs a power separation process.
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