Voltage Limiting Device for Constant Current Circuits

Method of limiting a voltage rise, comprising:

• connecting a current supply to output terminals,
• monitoring a voltage across the output terminals,
• clamping the voltage across the output terminals to a first voltage threshold when the voltage exceeds the first voltage threshold,
• short-circuiting the output terminals when the voltage across the output terminals exceeds a second voltage threshold for a predetermined time period.

Constant current circuit comprising a voltage limiting device, the voltage limiting device comprising:

• input terminals for connecting the voltage limiting device to a current supply of the constant current circuit,
• output terminals for connecting the voltage limiting device to a load of the constant current circuit, wherein the voltage limiting device is configured to have the input terminals connected to the output terminals under a normal operating condition,
• a voltage clamping circuit configured to clamp a voltage across the output terminals to a first voltage threshold, and
• a switching circuit configured to short-circuit the output terminals, the input terminals, or both the output terminals and the input terminals, when a second voltage threshold across the output terminals is exceeded for a predetermined time period.