Switch-mode power supply with dynamic adjustment of current sense magnitude

摘要

In a dc-to-dc converter, alternating current or pulsating direct current produced by a cyclically switched power supply passes through semiconductor rectifiers or diodes. The rectifiers may be subject to unwanted conduction characteristics attributable to charge storage, which may result in cyclical current spikes during normal operation. A current sensor is coupled to sense a current which includes the cyclical spikes. A controllable attenuator or gain element couples the sensed current in a feedback loop to shut down the converter in the event of an overcurrent. To reduce the possibility of shut-down due to the normal cyclical current spikes, the attenuator or gain element is cyclically switched so as to reduce the sensitivity to the current spikes when they occur.