This low power relay driver circuit can drive a 6 V relay from a 3.3 V . This low power relay driver circuit use a charge pump (IC MAX1681 configured as a voltage inverter) to produce the additional -3V needed to activate (pull in) the relay. Turning on Q1 with an external control signal
This high speed switching frequency allows the use of small (1μF) values for the input, output capacitors (C1, C3, and C2). These capacitors can be ceramic capacitors or tantalum capacitors .