An embodiment electronic circuit includes an electronic switch comprising a load path, a first protection circuit configured to generate a first protection signal based on a current-time-characteristic of a load current through the load path of the electronic switch, and a drive circuit configured to drive the electronic switch based on the first protection signal. The first protection circuit includes an analog-to-digital converter (ADC) configured to receive an ADC input signal representing the load current, to sample the ADC input signal once in each of a plurality of successive sampling periods, and to output an ADC output signal that includes a sequence of values such that each of the values represents a respective sample of the ADC input signal. The ADC is configured to pseudo-randomly select a sample time in each sampling period.

An embodiment electronic circuit includes an electronic switch comprising a load path, and a control circuit configured to drive the electronic switch. The control circuit is configured to operate in one of a first operation mode and a second operation mode based at least on a level of a load current of the electronic switch. In the first operation mode the control circuit is configured to generate a first protection signal based on a current-time-characteristic of the load current and drive the electronic switch based on the first protection signal. The control circuit is configured to generate a status signal such that the status signal has a wakeup pulse when the operation mode changes from the second operation mode to the first operation mode and, after the wakeup pulse, a signal level representing a level of the load current.

A protection IC protects an external load connected to mains supply lines from dangerous or undesired conditions such as overvoltage, undervoltage, and overcurrent, by disconnecting the external load for at least the duration of such a condition. The IC has a range detector, a zero-crossing detector, a control unit, a switch driver, and a dummy DAC. The range detector senses the presence of an unwanted condition. The control unit then waits for a zero crossing, upon which it disconnects the load. A lockout timer may introduce a minimum wait time before reconnecting the load. To prevent instabilities around the switching points, hysteresis in the window thresholds prevents impact from noise. The dummy DAC regulates a dummy current that linearizes the IC's current consumption around the switching points to prevent instabilities caused by positive feedback in non-linear transitions.

An apparatus comprises a switch, a current monitor, and a controller. During operation, the switch controls an amount of current through the load. The current monitor samples a magnitude of the current through the load, a magnitude of which varies over time during a time duration. Based on integrating the sample magnitudes of the current through the load over the time duration, the current monitor produces a current sense value. The current sense value is representative of an amount of current through the load. The controller controls an operational state of the switch based upon a comparison of the current sense value with respect to an over-current threshold value. For example, in response to detecting a condition in which the current sense value is greater than the overcurrent threshold value, the controller turns OFF (deactivates) the switch, reducing or eliminating delivery of current through the load.

A multi-level over-current protection circuit includes: a signal amplification circuit configured to receive a set of detection signals and output a first signal; a comparison circuit to compare the first signal with a first reference signal and a second reference signal respectively; and a time delay counting circuit. The time delay counting circuit adjusts a first count value when the first signal is higher than or equal to the first reference signal and smaller than the second reference signal, and the time delay counting circuit activates a protection mode when the first count value reaches a first protection time delay. The time delay counting circuit adjusts a second count value when the first signal is higher or equal to the second reference signal, and activates the protection mode when the second count value reaches a second protection time delay.

An electrical sensor is described. The electrical sensor including an electrical signal input configured to receive an electrical signal, an alarm, one or more inputs configured to set a configuration value and at least one display configured to display said configuration value. The monitor is coupled with the electrical signal input, the alarm, the display, and the one or more inputs. Further, the monitor is configured to determine a characteristic of the electrical signal received on the electrical signal input. The monitor is configured to activate the alarm based on the configuration value set by the one or more inputs and the characteristic of the electrical signal. And, the monitor configured to generate at least one display signal based on the configuration value to be used by the at least one display to display the configuration value.

While transient current magnitudes at different locations within a DC distribution system themselves are not a reliable indicator of fault location, it is recognized herein that accumulating energy or pseudo energy values provides a reliable basis for tripping the protection element at a fault location. Thus, in one aspect of the teachings herein, pseudo energy values are accumulated independently during a fault condition, for each of one or more protected branch circuits and the protection element for each such branch circuit is tripped responsive to the accumulated pseudo energy values reaching a defined pseudo energy threshold. The pseudo energy thresholds are defined so that the protection element in the branch circuit where the fault is located will trip first.

An overcurrent detection circuit installed in a host for supplying power to a device is disclosed. The overcurrent detection circuit includes: a detection resistor disposed on a power supply line; a current monitoring unit that compares a detected voltage that is a voltage drop across the detection resistor with a variable threshold voltage and asserts an overcurrent detection signal if the detected voltage exceeds the threshold voltage; and a control unit including a timer. The control unit is switchable among (i) a first state where the threshold voltage is set to a first value that is in accord with a reference value for overcurrent protection, (ii) a second state where the threshold voltage is set to a second value that is greater than the first value, and (iii) a third state where the threshold voltage is set to a third value that is less than the first value.

A circuit breaker is disclosed for interrupting an electrical circuit when current limit values are exceeded. The circuit-breaker includes a current sensor for determining the electrical current flow and a control device. When current limit values are exceeded, the electrical circuit is interrupted. A first current limit value, when exceeded, results in an immediate interruption and a second current limit value, when exceeded, results in a time-delayed interruption, such that the second interruption time reduces as the current increases. Only one control element is included for setting a current limit value. The element defining the second current limit value is included for the time-delayed interruption of the electrical circuit. The other parameters are either set in a fixed manner and/or are related to the settable second current limit value.

The present invention relates to current pulse limiting protection of a motorized device that includes a motor, a controller, and a power source (such as a battery). The controller implements current pulse limit protection to protect the controller and battery from damage due to overcurrent pulse events. For example, the controller may measure current flowing through the controller, and detect a number of current pulses that meets or crosses a first current threshold, regardless of a duration of each of the current pulses. The controller counts each current pulse that meets or crosses the first current threshold, and if the number of current pulses counted meets or exceeds a threshold number of pulses, the controller indicates a fault and ceases operation of the tool to protect the controller and battery from damage.