A sampling method for reduction of power in battery operated receivers

The use of low power UHF wireless links is prevalent in a variety of battery operated devices including remote entry systems and control in both industrial and consumer applications. Much effort has been invested in reducing power consumption, especially in receivers for applications in which the receiver must be on at all times. Commercial devices can be obtained that consume only a few mA in continuous operation. In addition, methodologies such as poling and power cycling have been deviced to further reduce power consumption in receivers. Nevertheless, none of these methods is sufficient for truly low power needs such as in inaccessible sensors or embedded active RFID systems. The current work describes a simple method of power reduction that relies on sampling the receiver's output for extremely short periods and turning the receiver on only when data is present. Otherwise the receiver is in an off mode. Power reductions attainable using the methods and circuits described here are far beyond what can be achieved using traditional methods. Circuits and power budgets for some existing UHF receivers are given as examples.