Abstract: A constant power limiter includes a control circuit and a power source circuit thereof, and the control circuit includes a voltage detection circuit configured for detecting a voltage of power source; a current detection circuit configured for detecting a load current; a zero-cross detection circuit configured for detecting a zero-cross point of AC power; a load driving circuit including a controlled silicon; and a micro control unit (MCU) configured for receiving output signals from the voltage detection circuit, the current detection circuit, and the zero-cross detection circuit, and outputting a control signal respectively to the load driving circuit to control a load power, wherein when the load power is less than or equal to a set power value, the load driving circuit has the controlled silicon fully open, when load power is no less than the set power value, the load driving circuit has the controlled silicon conduction angle decreased to stabilize the load power at the set power value.

Abstract: The invention relates to a method for providing short-circuit protection for a resistive AC load, wherein the load is connected with an AC power supply through an active controlled switch controlled by a controller. The method for providing short-circuit protection for the resistive AC load comprises the following steps of: turning on the active controlled switch within a first conduction angle range; obtaining the mean current value of the load through a current detection circuit; and determining whether the mean current value of the load is greater than a default value or not, wherein, if so, the active controlled switch is controlled to be turned off, and if not, the active controlled switch is controlled to be turned on. The invention also relates to a device and a switch for providing short-circuit protection for the resistive AC load.

Abstract: The invention relates to a method for providing short-circuit protection for a resistive AC load, wherein the load is connected with an AC power supply through an active controlled switch controlled by a controller. The method for providing short-circuit protection for the resistive AC load comprises the following steps of: turning on the active controlled switch within a first conduction angle range; obtaining the mean current value of the load through a current detection circuit; and determining whether the mean current value of the load is greater than a default value or not, wherein, if so, the active controlled switch is controlled to be turned off, and if not, the active controlled switch is controlled to be turned on. The invention also relates to a device and a switch for providing short-circuit protection for the resistive AC load.

Abstract: A constant power limiter includes a control circuit and a power source circuit thereof, and the control circuit includes a voltage detection circuit configured for detecting a voltage of power source; a current detection circuit configured for detecting a load current; a zero-cross detection circuit configured for detecting a zero-cross point of AC power; a load driving circuit including a controlled silicon; and a micro control unit (MCU) configured for receiving output signals from the voltage detection circuit, the current detection circuit, and the zero-cross detection circuit, and outputting a control signal respectively to the load driving circuit to control a load power, wherein when the load power is less than or equal to a set power value, the load driving circuit has the controlled silicon fully open, when load power is no less than the set power value, the load driving circuit has the controlled silicon conduction angle decreased to stabilize the load power at the set power value.