BOOSTING_OUTPUT_CURRENT

Published:2009/7/19 22:06:00 Author:Jessie | From:SeekIC

External NPN pass transistor is added to each section of LM125 precision dual tracking regulator to in-crease maximum output current by factor equal to beta of transistor. To prevent overheating and destruction of pass transistors and result, ant damage to regulator, series resistor RCL, is used to sense load current. When voltage drop across RCL equals current-limit sense voltage in range of about 0.3 to 0.8 V (related to junction temperature), regulator will current-limit. Maximum load current is about 1A for 25℃ junction and 0.6 ohm for RCL. LM125 provides ±15V, LM126 provides ±12V, and LM127 provides +5V and -12V.-T. Smathers and N. Sevastopoulos, LM125/LM126/LM127 Precision Dual Tracking Regulators, National Semiconductor, Santa Clara, CA, 1974, AN-82, p 5.



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