Backup tripping function for a circuit breaker with microcontroller-based fault detection

A backup circuit for a circuit breaker capable of microcontroller-based fault detection having a timing circuit for causing the circuit breaker to trip in response to the microcontroller being unresponsive or a failure of a power supply powering the microcontroller, comprising:

• a power supply that produces a regulated direct current (DC) voltage derived from an alternating current (AC) line voltage to which the circuit breaker is connected;
• a line-powered timing circuit and an electronic switch device connected in parallel with the timing circuit for causing the circuit breaker to trip in response to the electronic switching device being turned on;
• and
• a microcontroller powered by the power supply and including a first pin connected to the gate of the electronic switching device,
• wherein the first pin is configurable as a high-impedance input or as an output,
• wherein a resistor is connected between a first terminal of the electronic switching device and the gate, and a capacitor is connected between the gate and a second terminal of the electronic switching device,
• wherein the microcontroller is configured to pull the first pin to a logic level low output state, which shorts out the capacitor, and
• wherein the microcontroller is programmed to pull the first pin to a logic level high output state.

A circuit breaker capable of microcontroller-based fault detection having a timing circuit for causing the circuit breaker to trip in response to the microcontroller being unresponsive or a failure of a power supply powering the microcontroller, comprising:

• a power supply that produces a regulated direct current (DC) voltage derived from an alternating current (AC) line voltage to which the circuit breaker is connected;
• a line-powered timing circuit and a field effect transistor (FET) connected in parallel with the timing circuit for causing the circuit breaker to trip in response to the FET being turned on;
• and
• a microcontroller powered by the power supply and including a first pin coupled to the gate of the electronic switching device, wherein a resistor is connected between a first terminal of the FET and the gate, and a capacitor is connected between the gate and a second terminal of the FET.

A circuit breaker capable of microcontroller-based fault detection having a timing circuit for causing the circuit breaker to trip in response to the microcontroller being unresponsive or a failure of a power supply powering the microcontroller, comprising:

• a power supply that produces a regulated direct current (DC) voltage derived from an alternating current (AC) line voltage to which the circuit breaker is connected;
• a line-powered timing circuit and an electronic switch device connected in parallel with the timing circuit for causing the circuit breaker to trip in response to the electronic switching device being turned on;
• and
• a microcontroller powered by the power supply and including a first pin coupled to the gate of the electronic switching device, wherein a resistor is connected between a first terminal of the electronic switching device and the gate, and a capacitor is connected between the gate and a second terminal of the electronic switching device,
• wherein the first pin is configurable as a high-impedance input or as an output, and wherein the microcontroller is configured to pull the first pin to a logic level low output state shorting out the capacitor of the timing circuit, the microcontroller being programmed to pull the first pin to a logic level high output state in response to detection of a fault in a circuit to which the circuit breaker is connected.