In certain aspects, an apparatus includes a first power chain, a second power chain, and an enable circuit having an output coupled to an input of the first power chain. The apparatus also includes a multiplexer having a first input coupled to an output of the first power chain, a second input coupled to the output of the enable circuit, and an output coupled to an input of the second power chain, wherein the multiplexer is configured to receive a select signal, and couple the first input or the second input to the output of the multiplexer based on the select signal.