Voltage-limiting circuit and field device comprising such a voltage-limiting circuit

A voltage-limiting circuit for an ignition protection type “ia,” comprising:

• precisely two monolithic voltage-limiting modules, each voltage-limiting module including:
• a supply voltage connection;
• a circuit ground connection;
• a voltage divider for providing a divider voltage, wherein the voltage divider is arranged between the supply voltage connection and the circuit ground connection;
• a controller with a control signal output for outputting a control signal;
• and
• an actuator with an actuator signal input and a current channel, wherein the resistance value of the current channel is based on a signal applied to the actuator signal input,
• wherein the current channel runs parallel to the voltage divider between the supply voltage connection and the circuit ground connection,
• wherein an input of the controller is supplied with the divider voltage of the voltage divider,
• wherein the control signal output is connected to the actuator signal input, and
• wherein the supply voltage connection and the circuit ground connection of the two voltage-limiting modules are to be arranged parallel to a supply voltage source.

A field device for process automation technology, comprising:

• a sensor;
• a measuring and operating circuit for operating the sensor and for processing signals from the sensor;
• and
• a supply circuit including:
• a supply voltage source for supplying the measuring and operating circuit;
• and
• a voltage-limiting circuit for an ignition protection type “ia,” including:
• precisely two monolithic voltage-limiting modules, each voltage-limiting module including:
• a supply voltage connection;
• a circuit ground connection;
• a voltage divider for providing a divider voltage, wherein the voltage divider is arranged between the supply voltage connection and the circuit ground connection;
• a controller with a control signal output for outputting a control signal;
• and
• an actuator with an actuator signal input and a current channel, the resistance value of the current channel is based on a signal applied to the actuator signal input,
• wherein the current channel runs parallel to the voltage divider between the supply voltage connection and the circuit ground connection,
• wherein an input of the controller is supplied with the divider voltage of the voltage divider,
• wherein the control signal output is connected to the actuator signal input, and
• wherein the supply voltage connection and the circuit ground connection of the two voltage-limiting modules are connected parallel to the supply voltage source.