A power management device comprises: an input for receiving a transient energy pulse; a first storage section and a second storage section for storing energy from the input; an output; a switching section for selectively connecting the input, first storage section, second storage section and output in at least first and second configurations, wherein in the first configuration the first and second storage sections are connected so as to distribute energy from the transient energy pulse between the first and second storage sections, in the second configuration the respective voltages across the first and second storage sections are combined additively to produce an output voltage at the output, whereby the output voltage after switching to the second configuration is greater than the output voltage before switching to the second configuration.