Abstract: There is provided a method of detecting offset in a sense amplifier of an SRAM memory unit. The method comprises using a sense amplifier of the SRAM memory unit to implement a read of a first data value stored in a memory cell of the SRAM memory unit, and measuring a first time for the sense amplifier to read the first data value. The method further comprises using the sense amplifier to implement a read of a second data value stored in a memory cell of the SRAM memory unit, and measuring a second time for the sense amplifier to read the second data value. The method then comprises calculating a difference between the first time and the second time, and determining whether an offset adjustment should be applied to the sense amplifier in dependence upon the difference between the first time and the second time.

Abstract: A signal line driving circuit with power control for selectively reducing internal power dissipation when driving an external load. While driving the external load with a constant current the output voltage generated across such load is monitored. If the load impedance decreases sufficiently to cause the output voltage to fall below a predetermined threshold value and, therefore, cause the voltage across the signal line driving circuit to increase, the magnitude of the power supply voltage is automatically reduced, thereby reducing the voltage across the signal line driving circuit. Such a signal line driving circuit is particularly advantageous as a subscriber line interface circuit (SLIC). As the subscriber goes from an on-hook condition to an off-hook condition and if the subscriber loop is sufficiently short (or low in impedance), a lower power supply voltage is used to minimize the power dissipation of the SLIC while still maintaining the required subscriber loop current.

Abstract: A transient signal detector for monitoring a signal line and generating a control signal which indicates when the magnitude of a differential signal on the line exceeds either a positive or negative threshold value. The threshold value is defined by a single current, thereby allowing for a single, simple adjustment of such threshold in both the positive and negative directions.

Abstract: A transient signal detector for monitoring a signal line and generating a control signal which indicates when the magnitude of a differential signal on the line exceeds either a positive or negative threshold value. The threshold value is defined by a single current, thereby allowing for a single, simple adjustment of such threshold in both the positive and negative directions.

Abstract: A subscriber line interface circuit which includes a transient signal detector with temporal hysteresis. During steady state operation, the drive current for the subscriber loop allows the loop to respond to changes in loop conditions according to a steady state time constant of the loop filter. Upon detection of a line voltage transient which exceeds a predetermined threshold in either a positive or negative direction, the filter time constant is significantly reduced (e.g., 100:1) and held at such reduced value following the initial transient and for a predetermined time period after the line voltage has fallen back below such predetermined threshold. This allows the transient conditions to be fully compensated prior to resetting the filter time constant back from the lower transient value to the higher steady state value.