Abstract: A solid state power controller for switching power on and off to an electrical load which also serves as a circuit protection device protecting the load and/or the wire connected between the load output terminal of the controller and ground from thermal damage due to current overload is shown. Upon current overload the controller interrupts current to the load in a time inversely proportional to the square of the magnitude of the overload. The controller also limits the load current to a selected maximum level by controlling the drain-source resistance of power MOSFETs (PS1-7) used for switching power. A secondary interrupt is provided in the event that the junction temperature of the MOSFETs has risen to a selected maximum level. A thermal memory feature is included for both interrupt signals. The controller is controlled by a single on/off input line (COMMAND) and provides both a status (STATUS) and trip (TRIP) output line. The status can be configured to monitor load voltage or load current flow.

Abstract: A capacitive transducer (10) has a housing (12) which receives a variable capacitor (14) in a fluid pressure receiving chamber (12e). A support (20) is received on an annular shoulder (12j) formed in the sidewall (12h) of the housing. The support has inner and outer concentric ring shaped lands (20k, 20l) with the inner ring shaped land engaging the variable capacitor (14) inboard of the outer peripheral edge of the capacitor. A shelf (20d) is formed on the sidewall of the support which receives a first relatively rigid substrate (26a) of a circuit board which has a second relatively rigid substrate (26b) bent through a connecting flexible strip so that the second substrate overlies the first substrate within a circuit receiving chamber (20c). A ratiometric signal conditioning circuit portion 28a and voltage regulating circuit portion 28b are mounted on the circuit board.

Abstract: A solid state power controller for switching power on and off to an electrical load which also serves as a circuit protection device protecting the load and/or the wire connected between the load output terminal of the controller and ground from thermal damage due to current overload is shown. When a current overload exists the controller interrupts current to the load in a time inversely proportional to the square of the magnitude of the overload as shown in a trip time vs load current curve. The controller also limits the load current to a selected maximum level by controlling the drain-source resistance of power MOSFETs used for switching the power. A secondary interrupt is provided in the event that the junction temperature of the MOSFETs has risen a selected maximum level. A thermal memory feature is included for both interrupt signals. The controller is controlled by a single on/off input line and provides both a status and trip output line to indicate its state.

Abstract: A solid state power controller for switching power on and off to an electrical load which also serves as a circuit protection device protecting the load and/or the wire connected between the load output terminal of the controller and ground from thermal damage due to current overload is shown. When a current overload exists the controller interrupts current to the load in a time inversely proportional to the square of the magnitude of the overload as shown in a trip time vs load current curve. The controller also limits the load current to a selected maximum level by controlling the drain-source resistance of power MOSFETs used for switching the power. A secondary interrupt is provided in the event that the junction temperature of the MOSFETs has risen a selected maximum level. A thermal memory feature is included for both interrupt signals. The controller is controlled by a single on/off input line and provides both a status and trip output line to indicate its state.

Abstract: A solid state power controller for switching power on and off to an electrical load which also serves as a circuit protection device protecting the load and/or the wire connected between the load output terminal of the controller and ground from thermal damage due to current overload is shown. When a current overload exists the controller interrupts current to the load in a time inversely proportional to the square of the magnitude of the overload as shown in a trip time vs load current curve. The controller also limits the load current to a selected maximum level by controlling the drain-source resistance of power MOSFETs used for switching the power. A secondary interrupt is provided in the event that the junction temperature of the MOSFETs has risen a selected maximum level. A thermal memory feature is included for both interrupt signals. The controller is controlled by a single on/off input line and provides both a status and trip output line to indicate its state.

Abstract: A protective circuit capable of remotely switching power to a load on and off and including an electrothermal sensor system having a heating element of predetermined resistance in series with the load and source of power whereby the temperature of the heating element is monitored relative to ambient temperature to determine current flow in the heater. The electrothermal sensor, according to one embodiment, includes a ceramic substrate having the heater formed thereon with a first deposited heat monitoring element thereon for monitoring the temperature of the heater and a second heat monitoring element thereon for monitoring the ambient temperature of the substrate remote from the heater. The electrothermal sensor, according to a second embodiment, includes a layer of electrically conductive material, a backing layer thereon of electrically insulating material, a grid on the backing layer of thermoresponsive material to form RTDs and a second layer of electrically insulating material over said grid.

Abstract: A protective circuit capable of remotely switching power to a load on and off and including an electrothermal sensor system having a heating element of predetermined resistance in series with the load and source of power whereby the temperature of the heating element is monitored relative to ambient temperature to determine current flow in the heater. The electrothermal sensor, according to one embodiment, includes a ceramic substrate having the heater formed thereon with a first deposited heat monitoring element thereon for monitoring the temperature of the heater and a second heat monitoring element thereon for monitoring the ambient temperature of the substrate remote from the heater. The electrothermal sensor, according to a second embodiment, includes a layer of electrically conductive material, a backing layer thereon of electrically insulating material, a grid on the backing layer of thermoresponsive material to form RTDs and a second layer of electrically insulating material over said grid.