Abstract: The present invention provides fluorogenic probes and corresponding fluorescent compounds, methods of using the probes, compounds and kits that include the probes.

Abstract: A programmable delay circuit employs a comparator to control an output driver. The comparator compares a ramp signal with a disable signal or an error control signal derived from an error amplifier. The comparator latches the output on until a reset signal is received. The reset signal is produced when the ramp signal is discharged below a predetermined level. The programmable delay circuit is useful in a secondary side post regulator to control a grounded totem pole driver. The totem pole driver in turn controls a switching device coupled to a voltage on a secondary winding.

Abstract: An op amp clamp for charging or discharging a capacitor prevents the voltage on the capacitor from going beyond a reference voltage determined by a reference clamp voltage applied to an input of a differential amplifier. The second input of the differential amplifier is connected to the capacitor. The output of the differential amplifier is provided in a feedback loop to the capacitor. The feedback loop includes a charging circuit or a discharging circuit depending upon the function of the op amp clamp. The feedback loop may be arranged with a current mirror in which current generated by the output of the differential amplifier is mirrored in the charging or discharging circuit. A signal to activate charging or discharging is applied at the output of the differential amplifier to activate or deactivate the current mirror.