Abstract: EEPROM memory matrix in which column lines are alternatively used as detector lines. A precharge voltage is applied to selected detector lines together with the relevant column line in each case before read-out of the memory columns. If a detector line loses its precharge level during the read-out of the memory cells, light incidence is assumed and a corresponding alarm function is triggered. Preferably column lines adjacent to the column lines that are respectively selected for the data transmission are connected as detector lines.

Abstract: A method for controlling the charging and discharging phases of a backup capacitor for a data storage medium has the step where the backup capacitor is first discharged to a defined voltage level before it is charged. The capacitor is discharged using a constant current. This ensures that the charging current for the backup capacitor cannot be used to identify what the charge-state of the capacitor was before discharging. Therefore, it is no longer possible to infer the currents that flowed during security-related arithmetic operations in a data processing unit. In one advantageous circuit configuration, a constant current source is formed by a current-mirror circuit, and a comparator is used to compare the voltage on the backup capacitor with a bandgap reference.

Abstract: EEPROM memory matrix in which column lines are alternatively used as detector lines. A precharge voltage is applied to selected detector lines together with the relevant column line in each case before read-out of the memory columns. If a detector line loses its precharge level during the read-out of the memory cells, light incidence is assumed and a corresponding alarm function is triggered. Preferably column lines adjacent to the column lines that are respectively selected for the data transmission are connected as detector lines.

Abstract: A method for controlling the charging and discharging phases of a backup capacitor for a data storage medium has the step where the backup capacitor is first discharged to a defined voltage level before it is charged. The capacitor is discharged using a constant current. This ensures that the charging current for the backup capacitor cannot be used to identify what the charge-state of the capacitor was before discharging. Therefore, it is no longer possible to infer the currents that flowed during security-related arithmetic operations in a data processing unit. In one advantageous circuit configuration, a constant current source is formed by a current-mirror circuit, and a comparator is used to compare the voltage on the backup capacitor with a bandgap reference.

Abstract: A circuit configuration for detecting a functional disturbance has a first and a second differential amplifier. The outputs of the differential amplifiers are connected to the inputs of a gate. One input of the differential amplifiers is in each case connected to a reference potential terminal. The respective other input of the first and second differential amplifiers is connected to a monitoring means, which responds in the event of a change in the supply voltage at a supply potential terminal of the circuit configuration.

Abstract: A circuit configuration for detecting a functional disturbance has a first and a second differential amplifier. The outputs of the differential amplifiers are connected to the inputs of a gate. One input of the differential amplifiers is in each case connected to a reference potential terminal. The respective other input of the first and second differential amplifiers is connected to a monitoring means, which responds in the event of a change in the supply voltage at a supply potential terminal of the circuit configuration.