A power supply for an electronic circuit enables a low effort retention mode. During a normal mode a circuit module is supplied a first voltage sufficient for a controlled circuit to operate. During the low effort retention mode the circuit module is supplied with a second voltage lower than the first voltage. The second voltage is sufficient for flop-flops to retain their state but not sufficient to guarantee proper circuit operation. The second voltage is produced by a voltage drop (droop) from the first voltage. The preferred embodiment includes a System On Chip and one external voltage regulator and an on-chip droop circuit for each circuit module.