This paper considers the problem of conserving energy in a single node in a wireless sensor network by turning off the node's radio for periods of a fixed time length. While packets may continue to arrive at the node's buffer during the sleep periods, the node cannot transmit them until it wakes up. The objective is to design sleep control laws that minimize the expected value of a cost function representing both energy consumption costs and holding costs for backlogged packets. Large number of very small size, low cost, low power multifunctional sensor nodes constitute the WSN. These sensors way the understanding of the physical world by sensing, processing and transmitting the data. The above functions are highly influenced by factors such as power, energy and lifetime of the sensor nodes. This technical paper explores various low power design architectures like reconfigurable hardware, sleep walker, variable dual VDD, modular architecture and folded tree architecture by presenting a comprehensive survey concerning passive and active power control mechanisms in WSN with investigation of the existing solution and evaluation. © 2006-2016 Asian Research Publishing Network (ARPN). All rights reserved.