Abstract: An electronic protection system includes an electronic protection IC, mains power lines including a line rail and a neutral rail, a power switch, and a current sense device. A load is coupled with the mains power lines via the power switch and the current sense device. The electronic protection circuit turns off the power switch within eighty (80) milliseconds from a zero crossing in power delivered by the mains power lines when a load current is too high. A dummy DAC supplies a dummy current to prevent instability resulting from positive feedback during a change between a first state and a second state. The system may include an overcurrent detection circuit with a sense input, a comparator, a latch, and a pulse generator, configured to output a train of pulses with a low duty cycle when a current amplitude exceeds a reference value.

Abstract: 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.

Abstract: 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.

Abstract: A drive circuit and a method for maintaining an operating state of the drive circuit. The drive circuit includes a capacitor connected to an inverting input terminal of an operational amplifier and to a terminal of a current sensitive load through a switch. The output of the operational amplifier is connected to a switching regulator which has an output terminal connected to another terminal of the current sensitive load. An energy storage element is connected to the inverting input terminal of the operational amplifier. Energy is stored in the energy storage element during a first portion of a PWM pulse which is used during a second portion of the PWM pulse to generate the error signal. A drive signal is generated from the error signal where the drive signal is used to generate a voltage that biases the current source during the second portion of the PWM pulse.

Abstract: A drive circuit and a method for maintaining an operating state of the drive circuit. The drive circuit includes a capacitor connected to an inverting input terminal of an operational amplifier and to a terminal of a current sensitive load through a switch. The output of the operational amplifier is connected to a switching regulator which has an output terminal connected to another terminal of the current sensitive load. An energy storage element is connected to the inverting input terminal of the operational amplifier. Energy is stored in the energy storage element during a first portion of a PWM pulse which is used during a second portion of the PWM pulse to generate the error signal. A drive signal is generated from the error signal where the drive signal is used to generate a voltage that biases the current source during the second portion of the PWM pulse.

Abstract: A voltage source switching circuit having switches capable of switching between different voltage sources with reduced voltage drop levels is disclosed. A selected one of the different voltage levels is output to a peripheral circuit or supplied to internal circuitry. In one embodiment, the switches are FET devices.