SYSTEM AND METHOD FOR PROVIDING OVERVOLTAGE PROTECTION

1 . An overvoltage protection circuit, comprising:

a voltage clamping device having a predefined voltage threshold at which it starts conducting to prevent an overvoltage condition; and

a switch operable to control a flow of current from a power source to the voltage clamping device, the switch being OFF to prevent a flow of current from the power source to the voltage clamping device in response to a voltage of the power source being less than the voltage threshold such that the voltage clamping device does not exhibit a leakage current, and the switch being ON to permit a flow of current from the power source to the voltage clamping device in response to the voltage of the power source being equal to or greater than the voltage threshold.

2 . The circuit of claim 1 , including;

a comparator having an output connected to a control of the switch, the comparator only turning ON the switch to permit a flow of current to the voltage clamping device in response to the voltage of the power source exceeding a comparator threshold, the comparator threshold being greater than or equal to the voltage threshold of the voltage clamping device.

3 . The circuit of claim 2 , wherein the comparator also turns the switch ON to permit a flow of current to the voltage clamping device in response to the voltage of the power source being less than the voltage threshold of the voltage clamping device by an amount of 2 volts or less.

4 . The circuit of claim 1 , wherein the power source includes:

an energy harvester operable to harvest energy from environmental conditions; and

an energy storage device operable to store energy harvested by the energy harvester.

5 . The circuit of claim 4 , wherein the energy harvesting device includes at least one solar cell.

6 . The circuit of claim 4 , including a diode connected to an output of the energy harvester, the diode being operable to prevent the energy storage device from backcharging into the energy harvester.

7 . The circuit of claim 1 , wherein the voltage clamping device includes at least one of a zener diode, a transient voltage suppressor, or a metal oxide varistor, and wherein the switch includes at least one of a solid state switch or an air gap relay.

8 . The circuit of claim 1 , wherein the voltage clamping device includes a zener diode, and wherein the voltage threshold of the voltage clamping device is a breakdown voltage of the zener diode.

9 . An overvoltage protection circuit, comprising:

a switch;

a voltage clamping device; and

a switch control controlling the switch such that the switch only turns ON to permit a flow of current to the voltage clamping device in response to an input voltage exceeding a voltage threshold.

10 . The circuit of claim 9 , wherein the voltage threshold is great than or equal to a breakdown voltage of the voltage clamping device, or is within 2 volts less than the breakdown voltage of the voltage clamping device.

11 . The circuit of claim 98 , wherein the voltage clamping device has a predefined breakdown voltage at which it is conducting and clamps an input voltage to permit a flow of current and prevent an overvoltage condition.

12 . The circuit of claim 9 , wherein the input voltage comes from a power source including:

an energy harvester operable to harvest energy from environmental conditions; and

an energy storage device operable to store energy harvested by the energy harvester.

13 . The circuit of claim 11 , including a diode connected to an output of the energy harvester, the diode being operable to prevent the energy storage device from backcharging into the energy harvester.

14 . The circuit of claim 8 , wherein the voltage clamping device includes at least one of a zener diode, a transient voltage suppressor, or a metal oxide varistor, and wherein the voltage the switch includes at least one of a solid state switch or an air gap relay.

15 . A method of providing overvoltage protection, comprising:

passing an electric current through a voltage clamping device to prevent an overvoltage condition in response to a power source voltage exceeding a voltage threshold of the voltage clamping device; and

preventing a flow of current from the power source to the voltage clamping device in response to a voltage of the power source being less than the voltage threshold of the voltage clamping device such that the voltage clamping device does not exhibit a leakage current.

16 . The method of claim 15 , including:

connecting the power source to an input of a switch; and

connecting the voltage clamping device to an output of the switch, the switch controlling a flow of current to the voltage clamping device.

17 . The method of claim 16 , wherein the voltage clamping devices includes at least one of a zener diode, a transient voltage suppressor, or a metal oxide varistor, and wherein the voltage the switch includes at least one of a solid state switch or an air gap relay.

18 . The method of claim 16 , including:

connecting a comparator to a control input of the switch such that switch only turns ON to permit a flow of current to the voltage clamping device in response to a voltage of the power source exceeding a voltage threshold.

19 . The method of claim 17 , wherein the voltage at which said step of passing an electric current through a voltage clamping device is performed is a voltage greater than or equal to the voltage threshold of the voltage clamping device, or is within 2 volts less than the voltage threshold of the voltage clamping device.

20 . The method of claim 15 , wherein the power source includes an energy harvester and an energy storage device, the method including:

using an energy harvester to harvest energy from environmental conditions;

storing the harvested energy in an energy storage device; and

connecting a diode between the energy harvester and the energy storage device to prevent the energy storage device from backcharging into the energy harvester.