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AssigneeNorand Corporation
InventorDavid C. Hacker
Estimating the term…
In a system including volatile memory, a battery backed memory may be available for preserving data in the event of a power failure. Low power condition is reliably sensed sufficiently in advance of supply voltage falling below a minimum operating voltage range so as to give an adequate time interval, e.g. 2.5 milliseconds for the saving of application operating system status. By using a voltage regulator signal which switches in a particularly sensitive manner toward a saturation or zero state well outside its normal control range to trigger a low power signal, such low power signal may provide a time interval of, e.g. from three to six milliseconds of advance warning of impending supply voltage failure. The system is particularly useful for hand-held data processing systems with rechargeable batteries since the regulator may provide its regulator signal as a common control signal for regulating multiple supply paths, and may only trigger the low power signal when all of such supply paths approach a failure condition.
In a system including power supply means for supplying a power supply voltage,
In a system including a plurality of power supply means for supplying respective power supply voltages,
The method of obtaining an early warning of a low power condition in a system wherein supply voltage is regulated by means of a voltage regulator which supplies a varying control output signal as input power is reduced within a normal operating range and which control output signal approaches a saturation condition as input power falls below its normal operating range, said method comprising monitoring said control output signal and sensing approach thereof to said saturation condition as an early warning of low power condition.
The method of obtaining an early warning of a low power condition in a system, said method comprising regulating a supply voltage by means of a voltage regulator, supplying from the voltage regulator a varying control output signal for automatically maintaining said supply voltage substantially at a selected value as input power is reduced within a normal operating range, said control output signal approaching a limit condition as input power falls below its normal operating range, and said method further comprising monitoring said control output signal and sensing approach thereof to said limit condition as an early warning of low power condition.
Dependencies are inferred from the claim text.