Managing power disruptions in a sensor network

A sensory network, comprising:

• a master device;
• and
• a sensor connected to the master device by a system bus,
• wherein the master device is configured to provide a supply current over the system bus to power the sensor communicate with the sensor over the system bus by modulating the supply current, and wherein sensor is configured to communicate with the master device over the system bus using voltage modulated signals, and
• wherein the sensor comprises:
• a first sensor pin connected to the system bus;
• a current supply circuit connected to the first sensor pin, the current supply circuit configured to generate a first current based on the supply current received from the master device through the first sensor pin;
• a second sensor pin connected to the system bus and a transmit circuit;
• a control circuit connected to the first sensor pin and the current supply circuit by a sensor bus and connected to the second sensor pin and the transmit circuit;
• a third sensor pin connected to a circuit ground by a first capacitor, the first capacitor having a capacitor voltage level;
• a voltage detection circuit connected to the third sensor pin, the voltage detection circuit configured to detect a voltage at the third sensor pin corresponding to the capacitor voltage level and to transmit an under-voltage signal to the control circuit when the voltage at the third sensor pin falls below a predetermined level;
• a clamp circuit connected to the current supply circuit and one or more other sensor circuits by the sensor bus, the clamp circuit configured to transmit an overcurrent signal to the control circuit when the first current exceeds a current drawn by the one or more other sensor circuits by a predetermined amount and configured to transmit an undercurrent signal to the control circuit when the first current does not exceed the current drawn by the one or more other sensor circuits;
• and
• a low power mode circuit connected to the control circuit by the sensor bus and connected to a CTANK capacitor by a fourth sensor pin, the CTANK capacitor connected to the system bus and circuit ground, wherein the low power mode circuit is configured to sink current from the CTANK capacitor when the low power mode circuit receives an activation signal from the control circuit and to stop sinking current from the CTANK capacitor when the low power mode circuit receives a deactivation signal from control circuit,
• wherein the control circuit is configured to transmit the activation signal to the low power mode circuit when the control circuit has received the under-voltage signal for a first predetermined length of time.

A method of managing power consumption in a sensor device, comprising:

• generating a first current using a current supply circuit, the first current based on a second current received through a system bus;
• detecting a voltage at a sensor pin of the sensor device using a voltage detection circuit, the voltage at the sensor pin corresponding to a capacitor voltage level of a first capacitor;
• transmitting an under-voltage signal to a control circuit using the voltage detection circuit when the voltage at the sensor pin falls below a predetermined level;
• transmitting, using the control circuit, an activation signal to a low power mode circuit when the control circuit has received the under-voltage signal for a first predetermined length of time;
• and
• sinking current from a CTANK capacitor to power the sensor device, using the low power mode circuit, when the low power mode circuit receives the activation signal from the control circuit.