MEMORY_REFRESHER

Published:2009/7/15 22:17:00 Author:Jessie | From:SeekIC

Delivers high-energy pulses in extremely low duty-cycle mode. Developed to provide memory-refresh pulses for MOS memory system from standby battery. Circuit is basically programmable UJT oscillator with divider R2-R3 setting threshold or trigger level. To complete one cycle and start next, UJT is turned off by zener. Current through L1 drops, and resulting negative transient at base of Darlington outs it off. This generates high-power pulse with very sharp rise and fall times. Charging sequence then starts again to give sustained oscillation. Article gives design equations.-J. P. Stein, PUT Delivers Ultra-Low-Power. High-Energy Pulses, EDN Magazine, Sept.1, 1972, p 51－52.



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