15Vpt Output - Panasonic KX-TDA0103XJ Service Manual

KX-TDA0103XJ / KX-TDA0104XJ / KX-TDA0108XJ / KX-TDA0103X / KX-TDA0104X / KX-TDA0108X

2) 15VPT Output

2-1) 15V PT Output
During normal operation FET Q401 is ON and connected to 15V output. Then regulated 15V is output. At that time the
comparator IC401 output is high, and the transistor Q402 is OFF.
When the 15VPT goes into the over current condition, the voltage difference occurs at detection resistors R401, R402 and
R403. The voltage of IC401 +terminal becomes lower than that of -terminal, and then output of IC401 becomes LOW. Q402
turns ON and Q401 turns OFF.
Consequently the fold back current limiting shuts down 15VPT output.
Refer to Fig. 3-2 (A), (B).
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