Digital_power_switching_for_SRAMs

Published:2009/7/24 12:29:00 Author:Jessie | From:SeekIC

This circuit shows DS1236 and DS1336 chips that are used to provide power switching. When larger operating currents are required in a battery-backed system, the 5-V supply and battery-supply switches within the DS1236 cannot be large enough to support the required load through VCCO with a reasonable voltage drop. When such large currents are required, the PF and PF outputs are provided to gate external power switching devices. Power to the load is switched from VCC to battery on power-down, and from battery to VCC on power-up. The DS1336 uses the PF to switch between VBAT and VCC. The load applied to the PF pin from the extemal switch is supplied by the battery. Thus, if a discrete switch is used, this load should be considered when sizing the battery. Dallas Semiconductors, Product Data Book, 1992/1993, p. 10-77.



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