Abstract: A simulated battery test device and method that is capable of testing a battery charging circuit and logic circuit to determine proper operation. An operational amplifier is used that can both source and sink current to simulate the operation of the battery. A battery low signal can be generated using the simulated battery test device to test a battery charging circuit and logic circuit in a battery low condition. In addition, a battery open signal can be generated to test the battery charging and logic circuit in a battery open condition. Charging currents are detected to determine if currents fall within an acceptable range.

Abstract: A simulated battery test device and method that is capable of testing a battery charging circuit and logic circuit to determine proper operation. An operational amplifier is used that can both source and sink current to simulate the operation of the battery. A battery low signal can be generated using the simulated battery test device to test a battery charging circuit and logic circuit in a battery low condition. In addition, a battery open signal can be generated to test the battery charging and logic circuit in a battery open condition. Charging currents are detected to determine if currents fall within an acceptable range.

Abstract: A simulated battery test device and method that is capable of testing a battery charging circuit and logic circuit to determine proper operation. An operational amplifier is used that can both source and sink current to simulate the operation of the battery. A battery low signal can be generated using the simulated battery test device to test a battery charging circuit and logic circuit in a battery low condition. In addition, a battery open signal can be generated to test the battery charging and logic circuit in a battery open condition. Charging currents are detected to determine if currents fall within an acceptable range.

Abstract: A circuit for measuring voltage of a battery or group of batteries whose terminals are not directly accessible. The battery or group of batteries can have three leads. First and second leads are connected to the voltage output of the battery and the third lead is connected to the return of the battery. The three leads may terminate in a three prong plug which may plug into a printed circuit board to form a module. The module can be connected into a rack via an edge connector. A battery voltage measurement circuit can be located on another printed circuit board which is also plugged into the rack. This other printed circuit board may be interconnected to the battery module by wire traces within the rack. Thus, there are one or more first connectors between the first lead of the battery or group of batteries and the charger. There are one or more second connectors between the second lead of the battery or group of batteries and an input of the voltage measurement circuit.

Abstract: A circuit for measuring voltage of a battery or group of batteries whose terminals are not directly accessible. The battery or group of batteries can have three leads. First and second leads are connected to the voltage output of the battery and the third lead is connected to the return of the battery. The three leads may terminate in a three prong plug which may plug into a printed circuit board to form a module. The module can be connected into a rack via an edge connector. A battery voltage measurement circuit can be located on another printed circuit board which is also plugged into the rack. This other printed circuit board may be interconnected to the battery module by wire traces within the rack. Thus, there are one or more first connectors between the first lead of the battery or group of batteries and the charger. There are one or more second connectors between the second lead of the battery or group of batteries and an input of the voltage measurement circuit.

Abstract: An address protection circuit (APC) for cross-checking the integrity of requests to read or write an addressable system memory in a fault-tolerant computer system. In a check mode, the APC checks each address and a source identification code of each memory access request from an address source. The source identification code and current bus address are compared to a range of addresses stored in the APC. If the current bus address is within an "authorized" range, access to that range of locations in the memory is allowed to the address source. If a current memory access request is not authorized, the APC asserts an error signal which may be used to transfer control to a redundant subsystem. The APC contains a content-addressable memory element that can be initialized by a subsystem processor with address ranges and type of access (e.g., read or write) allowed for each source. To enter the setup mode, the APC must first be addressed to switch the APC from its check mode.

Abstract: Data in a system having dynamic random access memories (DRAM's) is preserved despite loss of the primary source of electrical power to that system. A Flash RAM and a small auxiliary power source are employed by a controller independent of the system to transfer the DRAM contents to the Flash RAM immediately upon loss of primary system power. The data is also automatically returned to the DRAM after return of primary power with special data signals or sequences being utilized in a multiple controller environment so as to award the complete data recovery function to the first controller to demand attention.