System and method for quickly discharging a DC relay

1. A circuit for discharging a relay coil, the circuit comprising:

a first suppression circuit coupled across a control power source;

a switch;

a relay coil in series with the switch, wherein the relay coil and the switch are coupled across the control power source; and

a second suppression circuit coupled across the relay coil;

wherein the relay coil is configured to actuate at least one load switch when sufficiently energized by the control power source;

wherein the first suppression circuit is configured to discharge energy stored in the relay coil; and

wherein the second suppression circuit is configured to discharge energy stored in the relay coil.

2. The circuit of claim 1 , wherein the switch is configured to isolate the relay coil and the second suppression circuit from the first suppression circuit.

3. The circuit of claim 1 :

wherein the first suppression circuit is configured to discharge energy stored in the relay coil when the switch is closed; and

wherein the second suppression circuit is configured to discharge energy stored in the relay coil when the switch is open.

4. The circuit of claim 1 :

wherein the first suppression circuit is configured to discharge the energy stored in the relay coil in a first time period;

wherein the second suppression circuit is configured to discharge the energy stored in the relay coil in a preselected time period; and

wherein the first time period is greater than the preselected time period.

5. The circuit of claim 4 , wherein the first time period is approximately twice as much as the preselected time period.

6. The circuit of claim 1 , wherein the first suppression circuit is comprised of a zener diode in series with a diode.

7. The circuit of claim 6 , wherein the second suppression circuit is comprised of a zener diode in series with a diode.

8. The circuit of claim 1 :

wherein the second suppression circuit is comprised of a zener diode in series with a diode; and

wherein an anode of the diode is coupled to an anode of the zener diode.

9. The circuit of claim 1 :

wherein the second suppression circuit is comprised of a zener diode in series with a diode;

wherein the switch has a preselected voltage limit; and

wherein the zener diode has a breakdown voltage less than the preselected voltage limit of the switch.

10. The circuit of claim 9 , wherein the switch is a MOSFET switch.

11. The circuit of claim 10 , wherein the preselected voltage limit of the MOSFET switch is based on a characteristic of a body diode of the MOSFET switch.

12. The circuit of claim 9 , wherein the preselected breakdown voltage is selected based on the preselected voltage limit of the switch and a preselected release time for a relay comprising the relay coil.

13. A circuit for discharging a relay coil, the circuit comprising:

a control power source;

a first switch in series with the control power source;

a first parallel subcircuit in parallel with the control power source and the first switch, the first parallel subcircuit comprising a first diode in series with a first zener diode;

a second parallel subcircuit in parallel with the control power source and the first switch, the second parallel subcircuit comprising a MOSFET switch in series with a relay coil; and

a third parallel subcircuit in parallel with the relay coil, the third parallel subcircuit comprising a second diode in series with a second zener diode;

wherein the relay coil is configured to actuate at least one load switch when sufficiently energized by the control power source.

14. The circuit of claim 13 :

wherein the first parallel subcircuit is configured to discharge energy stored in the relay coil when the MOSFET switch is closed; and

wherein the third parallel subcircuit is configured to discharge energy stored in the relay coil when the MOSFET switch is open.

15. The circuit of claim 13 , wherein the MOSFET switch is configured to isolate the relay coil and the second parallel subcircuit from the first parallel subcircuit.

16. The circuit of claim 13 :

wherein the first parallel subcircuit is configured to discharge energy stored in the relay coil in a first time period;

wherein the third parallel subcircuit is configured to discharge energy stored in the relay coil in a preselected time period; and

wherein the first time period is greater than the preselected time period.

17. The circuit of claim 16 , wherein the first time period is approximately twice as much as the preselected time period.

18. The circuit of claim 13 , wherein an anode of the second diode is coupled to an anode of the second zener diode.

19. The circuit of claim 13 , wherein a cathode of the second diode is coupled to a cathode of the second zener diode.

20. The circuit of claim 13 :

wherein the MOSFET switch has a preselected voltage limit; and

wherein a preselected breakdown voltage of the second zener diode is based on the preselected voltage limit of the MOSFET switch and a preselected release time for a relay comprising the relay coil.

21. The circuit of claim 20 , wherein the breakdown voltage of the second zener diode is less than the preselected voltage limit of the MOSFET switch.