David G Freeman

US Patent:

53572033, Oct 18, 1994

Filed:

Jul 8, 1992

Appl. No.:

7/910685

Inventors:

John E. Landau - Dallas TX
Wallace E. Matthews - Richardson TX
David L. Freeman - Plano TX

Assignee:

Benchmarq Microelectronics, Inc. - Carrollton TX

International Classification:

H02J 704
G01N 27416
G01R 3136

US Classification:

324427

Abstract:

A battery detect circuit (32) is connected to the battery with the current input to the battery and extracted from the battery measured with a sense resistor (50) and then converted to charge and discharge pulses with a V/F converter (52). A microcontroller (64) is operable to increment a Nominal Available Charge (NAC) register (180) during a charge operation, and to increment a Discharge Count Register (DCR) (184) during a discharge operation. The NAC register (180) indicates the available charge, which value is output to a display (34). The maximum value to which the NAC value can rise is limited by a value stored in the last measured discharge register (182). This value represents the value stored in the DCR (184) whenever the battery is discharged from an apparent full state to a fully discharged state. This results in a qualified transfer to the LMD register (182) such that no knowledge of the actual battery charge is necessary. The microcontroller (64) is operable to determine the rate of discharge corresponding to the voltage across the sense resistor (50).

US Patent:

54402212, Aug 8, 1995

Filed:

Jul 8, 1992

Appl. No.:

7/910688

Inventors:

John E. Landau - Dallas TX
Wallace E. Matthews - Richardson TX
David L. Freeman - Plano TX

Assignee:

Benchmarg Microelectronics, Inc. - Dallas TX

International Classification:

H01M 1044
H01M 1046

US Classification:

320 22

Abstract:

A battery detect circuit (32) is connected to the battery with the current input to the battery and extracted from the battery measured with a sense resistor (50) and then converted to charge and discharge pulses with a V/F converter (52). A microcontroller (64) is operable to increment a Nominal Available Charge (NAC) register (180) during a charge operation, and to increment a Discharge Count Register (DCR) (184) during a discharge operation. The NAC register (180) indicates the available charge, which value is output to a display (34). The maximum value to which the NAC value can rise is limited by a value stored in the last measured discharge register (182). This value represents the value stored in the DCR (184) whenever the battery is discharged from an apparent full state to a fully discharged state. This results in a qualified transfer to the LMD register (182) such that no knowledge of the actual battery charge is necessary. The charge rate is varied as both a function of temperature, voltage and also of the state of charge.

US Patent:

52847195, Feb 8, 1994

Filed:

Jul 8, 1992

Appl. No.:

7/910687

Inventors:

John E. Landau - Dallas TX
Wallace E. Matthews - Richardson TX
David L. Freeman - Plano TX

Assignee:

Benchmarq Microelectronics, Inc. - Carrollton TX

International Classification:

H01M 1048

US Classification:

429 50

Abstract:

A battery detect circuit (32) is connected to the battery with the current input to the battery and extracted from the battery measured with a sense resistor (50) and then converted to charge and discharge pulses with a V/F converter (52). A microcontroller (64) is operable to increment a Nominal Available Charge (NAC) register (180) during a charge operation, and to increment a Discharge Count Register (DCR) (184) during a discharge operation. The NAC register (180) indicates the available charge, which value is output to a display (34). The maximum value to which the NAC value can rise is limited by a value stored in the last measured discharge register (182). This value represents the value stored in the DCR (184) whenever the battery is discharged from an apparent full state to a fully discharged state. This results in a qualified transfer to the LMD register (182) such that no knowledge of the actual battery charge is necessary.

US Patent:

54547105, Oct 3, 1995

Filed:

Feb 8, 1994

Appl. No.:

8/193439

Inventors:

John E. Landau - Dallas TX
Wallace E. Matthews - Richardson TX
David L. Freeman - Plano TX

Assignee:

Benchmarg Microelectronics, Inc. - Dallas TX

International Classification:

H01M 1048

US Classification:

429 50

Abstract:

A battery detect circuit (32) is connected to a battery, with the current A battery V:the battery and the current extracted from the battery measured with a sense resistor (50) and convened to charge and discharge voltages with a V/F converter (52). A microcontroller (64) is operable to increment a nominal available charge (NAC) register (180) during a charge operation and to increment a discharge rate counter (DCR) (184) during a discharge operation. The NAC register (180) indicates the available charge, i. e. the charge state of the battery, which value is output to a display (34). The display (34) is controlled to operate in either an absolute full mode or a relative full mode. This is determined by an external programming pin which has first and second programming states associated with the two modes. In the absolute full mode, a Programmed Full Count (PFC) determines the upper capacity value of the display (34), which PFC is predetermined and represents the maximum capacity of the battery when the battery is new. The charge state value displayed is then determined relative to the maximum capacity value.