Dual voltage level circuit for driving a latching relay

A driving circuit for driving a relay having a coil, the driving circuit comprising:

• a first relay driver having first and second switches selectively switchable to connect a first end of the coil with (a) a first current path between the first switch and a relay voltage input or (b) a second current path between the second switch and a ground connection;
• and
• a second relay driver having third and fourth switches selectively switchable to connect a second end of the coil with (a) a third current path between the third switch and the relay voltage input or (b) a fourth current path between the fourth switch and the ground connection;
• the switches operable to connect the coil between the second and third current paths to configure the driving circuit for latching of the relay, and operable to connect the coil between the first and fourth current paths to configure the driving circuit for unlatching of the relay;
• the driving circuit further configured to apply a first signal from the relay voltage input through the third switch to latch the relay, and to apply a second signal from the relay voltage input through the first switch to unlatch the relay, the first and second signals having opposite polarities, the first switch operable to unlatch the relay upon receiving the second signal at a voltage magnitude lower than a voltage magnitude of the first signal by which the third switch is operable to latch the relay.