Diagnosable reverse-voltage protection for high power loads

An electrical system comprising:

• an electric load;
• a power supply connected to the load;
• a reverse-voltage protection switch connected in a series-type configuration with the electric load and the power supply, the reverse-voltage protection switch including a first terminal, a second terminal, and a control terminal, the first terminal being coupled to the electric load, the second terminal being coupled to the power source, the reverse-voltage protection switch opening and closing a connection between the first terminal and the second terminal based on an input to the control terminal;
• a ground switch connected between the first terminal of the reverse-voltage protection switch and ground;
• a bias voltage source connected to the second terminal of the reverse-voltage protection circuit;
• and
• a control system configured to monitor the operation of the reverse-voltage protection switch by
• disconnecting the second terminal of the reverse-voltage protection switch from the power source;
• closing the ground switch to connect the first terminal of the reverse-voltage protection switch to ground;
• applying a biasing voltage to the second terminal of the reverse-voltage protection switch;
• opening the reverse-voltage protection switch;
• and
• determining that an improper short-circuit condition exists across the reverse-voltage protection switch when the voltage at the second terminal of the reverse-voltage protection switch is less than a threshold while the second terminal of the reverse-voltage protection switch is disconnected from the power source, the ground switch is closed, the reverse-voltage protection switch is opened, and the bias voltage is applied to the second terminal of the reverse-voltage protection switch.

An electrical system comprising:

• a power supply;
• an electric load;
• a high-side switch including a first terminal, a second terminal, and a control terminal, the high-side switch opening and closing a connection between the first terminal of the high-side switch and the second terminal of the high-side switch based on an input to the control terminal of the high-side switch, the high-side switch being connected between the power supply and the electric load in a series-type configuration such that the first terminal of the high-side switch is connected to the power supply and the second terminal of the high-side switch is connected to the electric load;
• a reverse-voltage protection switch including a first terminal, a second terminal, and a control terminal, the reverse-voltage protection switch opening and closing a connection between the first terminal of the reverse-voltage protection switch and the second terminal of the reverse-voltage protection switch based on an input to the control terminal of the reverse-voltage protection switch, the reverse-voltage protection switch being connected between the electric load and a low-side switch such that the first terminal of the reverse-voltage protection switch is connected to the electric load and the second terminal of the reverse-voltage protection switch is connected to the low-side switch;
• the low-side switch including a first terminal, a second terminal, and a control terminal, the low-side switch opening and closing a connection between the first terminal of the low-side switch and the second terminal of the low-side switch based on an input to the control terminal of the low-side switch, the low-side switch being connected between the reverse-voltage protection switch and the power supply in a series-type configuration such that the first terminal of the low-side switch is connected to the reverse-voltage protection switch and the second terminal of the low-side switch is connected to the power supply;
• a ground switch including a first terminal, a second terminal, and a control terminal, the ground switch opening and closing a connection between the first terminal of the ground switch and the second terminal of the ground switch based on an input to the control terminal of the ground switch, the first terminal of the ground switch being connected to the first terminal of the reverse-voltage protection switch and the second terminal of the ground switch being connected to ground;
• a bias voltage source connected to the second terminal of the reverse-voltage protection switch;
• a voltage measuring circuit connected to the second terminal of the reverse-voltage protection switch;
• and
• a control system connected to the control terminal of the high-side switch, the control terminal of the reverse-voltage protection switch, the control terminal of the low-side switch, and the control terminal of the ground switch, and configured to
• control operation of the electric load by selectively opening and closing the high-side switch and the low-side switch,
• monitor operation of the reverse-voltage protection switch by
• opening the low-side switch to disconnect the second terminal of the reverse-voltage protection switch from the power supply;
• opening the high-side switch to disconnect the electric load from the power supply;
• closing the ground switch to connect the first terminal of the reverse-voltage protection switch to ground;
• activate the bias voltage source to apply a bias voltage to the second terminal of the reverse-voltage protection switch;
• opening the reverse-voltage protection switch;
• and
• determining that an improper short-circuit condition exists across the reverse-voltage protection switch when the voltage at the second terminal of the reverse-voltage protection switch is less than a threshold while the high-side switch is open, the low-side switch is open, the ground switch is closed, the reverse-voltage protection switch is opened, and the bias voltage is applied to the second terminal of the reverse-voltage protection switch.