Sanyo VPC-E6 Service Manual

Contents

– 6 –1-4. ST1 STROBE CIRCUIT DESCRIPTION1. Charging CircuitWhen UNREG power is supplied to the charge circuit and theCHG signal from microprocessor becomes High (3.3 V), thecharging circuit starts operating and the main electorolyticcapacitor is charged with high-voltage direct current.However, when the CHG signal is Low (0 V), the chargingcircuit does not operate.1-1. Charging switchThe CHG signal becomes High, Q5406 becomes ON and thecharging circuit starts operating.1-2. Power supply filterC5406 constitutes the power supply filter. They smooth outripples in the current which accompany the switching of theoscillation transformer.1-3. Oscillation circuitThis circuit generates an AC voltage (pulse) in order to in-crease the UNREG power supply voltage when drops in cur-rent occur. This circuit generates a drive pulse with a frequencyof approximately 50-100 kHz. Because self-excited light omis-sion is used, the oscillation frequency changes according tothe drive conditions.1-4. Oscillation transformerThe low-voltage alternating current which is generated by theoscillation control circuit is converted to a high-voltage alter-nating current by the oscillation transformer.1-5. Rectifier circuitThe high-voltage alternating current which is generated atthe secondary side of T5401 is rectified to produce a high-voltage direct current and is accumulated at electrolytic ca-pacitor C5412.1-6. Voltage monitoring circuitThis circuit is used to maintain the voltage accumulated atC5412 at a constance level.After the charging voltage is divided and converted to a lowervoltage by R5405 and R5406, it is output as the monitoringvoltage VMONIT. When VMONIT voltage reaches a specifiedlevel, the CHG signal is switched to Low and charging is in-terrupted.2. Light Emission CircuitWhen FLCLT signals are input from the ASIC expansion port,the stroboscope emits light.2-1. Emission control circuitWhen the FLCLT signal is input to Hi at the emission controlcircuit, Q5409 switches on and preparation is made to thelight emitting. Moreover, when a FLCLT signal becomes Lo,the stroboscope stops emitting light.2-2. Trigger circuitThe Q5409 is turned ON by the FLCLT signal and light emis-sion preparation is preformed. Simultaneously, high voltagepulses of several kV are emitted from the trigger coil and ap-plied to the light emitter.2-3. Light emitting elementWhen the high-voltage pulse form the trigger circuit is ap-plied to the light emitting part, currnet flows to the light emit-ting element and light is emitted.Beware of electric shocks.