Automatic control means providing a low-power responsive signal, particularly for initiating data preservation operation

• US 4,845,419 A
• Filed: 10/06/1987
• Issued: 07/04/1989
• Est. Priority Date: 11/12/1985
• Status: Expired due to Term

• Current Assignee: Unova Incorporated (Honeywell International Inc.)
• Original Assignee: Norand Corporation (Baker Hughes Company)
• Inventors: Hacker, David C.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Ault, Anita M.
• Application Number:
  US07/107,494
• Time in Patent Office: 637 Days
• Field of Search: 320/2, 320/39, 323/299, 323/303
• US Class Current: 320/136
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G06F 1/263 Arrangements for using multiple switchable power supplies, e.g. battery and AC G06F1/30 takes precedence
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/4257 Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 50/213 adapted for cells having curved cross-section, e.g. round or elliptic H01M50/209, H01M50/216 take precedence
• CPC Class Codes: H01M 50/50 Current conducting connections for cells or batteries
• CPC Class Codes: H01M 50/569 Constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals battery terminal connectors with integrated measuring arrangements G01R31/364
• CPC Class Codes: H01M 6/5044 Cells or batteries structurally combined with cell condition indicating means
• CPC Class Codes: H01M 6/505 Cells combined with indicating means for external visualization of the condition, e.g. by change of colour or of light intensity
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00036 Charger exchanging data with battery
• CPC Class Codes: H02J 7/00038 using passive battery identification means, e.g. resistors or capacitors identification by mechanical connections H02J7/0045
• CPC Class Codes: H02J 7/00047 with provisions for charging different types of batteries
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/0049 Detection of fully charged condition
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: H02J 7/00711 : with introduction of pulses during the charging process
• CPC Class Codes: H02J 7/00712 : the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: H02J 7/00714 : in response to battery charging or discharging current
• CPC Class Codes: H02J 7/007194 : of the battery
• CPC Class Codes: H02J 9/061 : for DC powered loads
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y10S 320/16 : Removal of memory effect in batteries

Abstract

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.

Claims

1. In a system including power supply means for supplying a power supply voltage,

automatic voltage regulator means having input means coupled with said power supply means and automatically operable for supplying a regulated output power,

said automatic voltage regulator means producing a regulator signal which progressively changes as a function of a power supply voltage and approaches a limit range as power supply voltage is reduced below a given minimum value, and

signalling means coupled with said automatic voltage regulator means for supplying a low power signal to an external circuit when the regulator signal approaches said limit range.

2. A system according to claim 1, with said automatic voltage regulator means supplying the regulator signal in the form of a control signal for controlling output power from said regulator means, such control signal having a normal control range corresponding to normal output power being supplied from said regulator means, and having a saturation value which is approached when power supply voltage falls below the given minimum value.

3. A system according to claim 2, with said signalling means comprising logic means for supplying a first discrete logic signal level when the control signal is within said normal control range and for supplying a second discrete logic signal level distinct from said first logic signal level when the control signal approaches said saturation value.

4. A system according to claim 1, with an integrated circuit having a first operational amplifier means forming part of said automatic voltage regulator means, and a second operational amplifier means forming part of said signalling means and having an input means coupled with an output of said first operational amplifier means.

5. A system according to claim 1, with volatile memory means having a minimum operating voltage below said given minimum value of power supply voltage such that said low power signal gives a reliable advance warning in sufficient time to enable transfer of data to a nonvolatile storage.

6. In a system including a plurality of power supply means for supplying respective power supply voltages,

a plurality of individual current supply paths having respective current regulator means therein, and

a common control means having output means coupled to each of said current regulator means and supplying a common control signal which has a normal range so long as one of the power supply voltages is above a given minimum value and which approaches a saturation value when the respective power supply voltages are below their respective minimum values, for signalling a low power condition.

7. A system according to claim 6, with switch means controlling the respective current supply paths and operative for selectively switching the respecting current supply paths to a restricted current flow condition independently of the common control means.

8. A system according to claim 6, with said common control means comprising operational amplifier means supplying a common control voltage having a normal limit voltage, and supplying a saturation voltage value when the respective power supply voltages are below their respective minimum values, which voltage value is displaced from the normal range by a voltage differential at least approximately corresponding to the voltage differential between maximum and minimum values of the said range.

9. A system according to claim 8, with said operational amplifier means supplying a common control voltage having a normal range including a given normal limit voltage, and supplying a saturation voltage value when the respective power supply voltages are below their respective minimum values, which saturation voltage value has a ratio relative to the normal limit voltage of at least about two to one.

10. A system according to claim 6, with switch means controlling activation of the respective current supply paths, and responsive to the common control signal approaching said saturation value to automatically activate all of the current supply paths.

11. 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.

12. A method according to claim 11, with said control output signal varying by at least about fifty percent as the supply voltage falls about two percent from its normal operating range.

13. A method according to claim 11, with said control output signal varying by at least fifty percent as the supply voltage falls about two percent from its normal operating range, said method comprising sensing a change in the control output signal from a midrange value, of at least one hundred percent of such midrange value as an early warning of low power condition.

14. A method according to claim 11, with said control output signal varying by at least about fifty percent as the supply voltage falls about two percent from its normal operating range, said method comprising sensing a change in the control output signal from a midrange value, of a least about three hundred percent as an early warning of low power condition.

15. A method according to claim 11, with said control output signal varying by at least about fifty percent as the supply voltage falls about two percent below its normal operating range, and utilizing the sensing of said approach to saturation condition to initiate a memory protection routine.

16. 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.

17. A method according to claim 16, with said control output signal varying by at least about fifty percent as the supply voltage falls a small percent from its selected value.

18. A method according to claim 16, with said control output signal varying by at least fifty percent as the supply voltage falls a small percent from its selected value, said method comprising sensing a change in the control output signal from a midrange value, of at least one hundred percent of such midrange value as an early warning of low power condition.

19. A method according to claim 16, with said control output signal varying by at least about fifty percent as the supply voltage falls a small percent from its selected value, said method comprising sensing a change in the control output signal from a midrange value, of at least about three hundred percent as an early warning of lower power condition.

20. A method according to claim 16, with said control output signal varying by at least about fifty percent as the supply voltage falls a small percent below its selected value, and utilizing the sensing of said approach to limit condition to initiate a memory protection routine.