Read Panasonic KX-DT333RU Service Manual online
9
KX-DT333RU/KX-DT333RU-B
4.2.4.
Reset Circuit
Reset Signal is outputted from IC3 and inputted into IC1 and IC2 at the connection of TEL cord.
4.2.5.
Power Supply Circuit
This circuit converts the voltage supplied from PBX into the power supply voltage of +3.3V by IC5 (Switching Regulator IC).
IC10 controls the power supply circuit as below to turn IC5 on in low consumption current at starting up.
IC10 controls the power supply circuit as below to turn IC5 on in low consumption current at starting up.
• Input Voltage approx. 20V or less
→ L →IC5 ON
• Input Voltage approx. 20V or more
→ Q5 C (Collector) HiZ→IC6 OFF
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