Circuit and method for storing information in non-volatile memory during a loss of power event
A data storage circuit for storing data from volatile memory in response to a power loss, the data storage circuit including an input for receiving a power loss signal in response to a power loss from at least one power source, an input configured to receive data from a volatile memory, a single block of non-volatile matrix of memory cells and a driver circuit coupled to said single row of non-volatile matrix of memory cells. The driver circuit is configured to write data to and read data from said single block of non-volatile matrix of memory cells. The single block of non-volatile matrix of memory cells can be provided as a single row electrically erasable programmable read only memory (EEPROM).
1. A data storage circuit comprising:
a charge pump;
a main memory;
a turns count register;
a memory matrix of non-volatile memory cells;
a main memory controller coupled to said main memory;
an EEPROM memory block detached from the main memory controller and the memory matrix;
one or more EEPROM programming switches;
a first switch coupled between said charge pump and said EEPROM programming switches; and
a digital controller coupled to said first switch, said EEPROM programming switches and to said EEPROM wherein, in response to a loss of power to the turns count register, the digital controller places the first switch in a closed position such that said charge pump provides a signal which keeps the EEPROM programming switches biased for a period of time sufficient for data in the turns count register to be stored in a said detached EEPROM memory block.
2. The data storage circuit of claim 1 wherein said period of time is about 10 milliseconds or less.
3. The data storage circuit of claim 2 wherein the energy storage device is configured to store no more than about the energy required to keep the EEPROM programming switches biased for said period of time.
4. The data storage circuit of claim 1 wherein the turns count register is configured to store a value representing the angle of rotation of an object.
5. The data storage circuit of claim 4 wherein the object is the steering wheel of a vehicle.