Texas Instruments Corporation

Norman E LeComte

Thomas Richard Maher

Keith W Kawate

Sepideh H Nott

Dale R Sogge

Eric K Larson

Neal Pugh

Edward F Racca

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. The controller also can be configured to default to either an on or off state in the event the input line is disconnected. The controller is made so that it is externally programmable by providing selected external connection points (MPA, DTA, CLA1, CLA2) and choosing values of certain components (R.sub.cl1i, R.sub.cl2i, R.sub.ii, C.sub.ii, R.sub.mpi, C.sub.mpi) contained within the sealed controller package which results in a selected default condition.

Externally programmable solid state power controller with power switch

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. The voltage regulating circuit is used to convert the transducer into a variable supply/fixed output device and includes a precision voltage regulator (U2) having an input capability of a portion of the range of the variable supply voltage, an NPN transistor (Q1) to provide a variable resistance in the primary current path, a zener diode D3, a current regulating diode (D2) to bias the transistor and the zener diode, a blocking diode (D1) and associated capacitors (C13, C14, C15).

Voltage regulated pressure transducer apparatus

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. The status can be configured to monitor load voltage or load current flow as desired. The controller also can be configured to default to either an on or off state in the event the input line is disconnected.

Solid state power controller

Solid state power controller with power switch protection apparatus

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West Greenwich, RI, United States of America

Norman E LeComte