Patent ID: 7369969

Claim:
A holding device for a sensor signal from a sensor, comprising: a signal input receiving the sensor signal from the sensor; a signal output; a memory, which is coupled to the signal input and the signal output, the memory being operable in a first state to retain a stored signal value and prevent an updating of the stored signal value, and in a second state to update the stored signal value, wherein the updated stored signal value is based on the sensor signal, and wherein the memory is operable in the first state to retain the stored signal value for a time period that is greater than a first predetermined time duration, independently of a supply voltage of the memory, and wherein the memory comprises: a memory cell; and a switch or a switchable driver connected between an input of the memory and the memory cell, and configured to enable or disable the input of the memory, wherein any write access to the memory is blocked if the switch is open or the switchable driver is disabled during the first state; and a monitor, which is effectively coupled to the memory, and operable to determine whether the sensor signal present at the signal input is valid, and to ensure that the memory is in the second state only when the monitor identifies that the sensor signal at the signal input is valid, wherein the monitor is further operable to drive a control signal in such a way that an acceptance of data by the memory is possible only when the monitor has determined that the sensor signal is valid, wherein a state of the switch or switchable driver is controlled based on the control signal, and wherein the holding device is furthermore operable to output the signal value presenting the memory at the signal output.