Power driver having short circuit protection

Claim 2

A power driver with short circuit protection comprising: (a) control signal input means for receiving a control signal; (b) power switch means responsive to said control signal for completing a current path through a load, said power switch means including a transistor having a base and an emitter; (c) comparator means for comparing a reference signal with a sense signal, said sense signal being a function of base-emitter voltage for said transistor, and for providing a fault detected signal when said sense signal exceeds said reference signal; and (d) disable means responsive to said fault detected signal for disabling said transistor.

Claim 3

The power driver with short circuit protection of claim 1 wherein said disable means includes a flip-flop that responds to said control signal by providing an output signal that enables said power switch means to complete said current path.

Claim 4

The power driver with short circuit protection of claim 1 and further including a tristate buffer operably connected between said control signal input means and said base of said transistor.

Claim 5

The power driver with short circuit protection of claim 1 wherein said disable means further functions to provide dual mode disablement, such that a first disablement of said transistor comprises removing said control signal from said power switch means, and a second disablement mechanism comprises connecting said base of said transistor to ground.

Claim 6

The power driver with short circuit protection of claim 4 wherein said disable means includes a flip-flop, with one output of said flip-flop providing an enabling signal that, when removed, terminates provision of said control signal to said power switch means, and another output of said flip-flop functions to enable a switch that connects said base of said transistor to ground.

Claim 7

The power driver with short circuit protection of claim 1 wherein said disable means includes (a) a flip-flop for receiving said control signal and said fault detected signal and for selectively providing an enabling signal at one output and a disabling signal at a second output in response thereto; (b) an AND gate having a first input connected to receive the control signal and a second input connected to receive the enabling signal of said flip-flop, and an output connected to provide said control signal to said base of said transistor; and (c) an FET connected to be responsive to said disabling signal from said flip-flop to connect said base of said transistor to ground.

Claim 8

The power driver with short circuit protection of claim 6 and further including a tristate buffer having an input connected to said output of said AND gate and an output connected to said base of said transistor.

Claim 9

The power driver with short circuit protection of claim 1 wherein said disable means includes memory means for causing said disable means to continuously disable said transistor, once a fault detected signal has been provided by said comparator means, until a reenable signal has been provided to said memory unit.

Claim 10

The power driver with short circuit protection of claim 8 wherein said control signal has a rising edge and wherein said reenable signal comprises said rising edge.

Claim 11

The power driver with short circuit protection of claim 9 wherein said memory means includes a flip-flop having a clock port connected to said control signal input such that said rising edge of said control signal causes said flip-flop to clock.

Claim 12

A power driver with short circuit protection comprising: (a) control signal input means for receiving a control signal; (b) power switch means responsive to said control signal for completing a current path through a load, said power switch means including a transistor having a base and an emitter; (c) comparator means having a first input connected to receive a predetermined reference signal and a second input connected to said base of said transistor for receiving base-emitter voltage information, for providing a fault detected signal when said base-emitter voltage information exceeds said reference signal; and (d) disable means responsive to said fault detected signal for disabling said transistor, said disable means including: (i) a flip-flop having a clock input for receiving said control signal, a reset port connected to receive said fault detected signal from said comparator means, a Q output port, and a not Q output port; (ii) an AND gate having a first input connected to receive said control signal, a second input connected to said Q output port of said flip-flop, and an output for providing an enabling signal to said transistor; and (iii) an FET having a gate connected to said not Q output of said flip-flop and power terminals connected between said base of said transistor and ground.

Claim 13

A power driver with short circuit protection comprising: (a) control signal input means for receiving a control signal; (b) power switch means responsive to said control signal for completing a current path through a load, said power switch means including a transistor having a base and an emitter; (c) comparator means having a first input connected to receive a predetermined reference signal and a second input connected to said base of said transistor for receiving base-emitter voltage information, for providing a fault detected signal when said base-emitter voltage information exceeds said reference signal; and (d) disable means responsive to said fault detected signal for disabling said transistor, said disable means including: (i) a flip-flop having a clock input for receiving said control signal, a reset port connected to receive said fault detected signal from said comparator means, a Q output port, and a not Q output port; (ii) an AND gate having a first input connected to receive said control signal, a second input connected to said Q output port of said flip-flop, and an output for providing an enabling signal to said transistor; and (iii) an FET having a gate connected to said not Q output of said flip-flop and power terminals connected between said base of said transistor and ground.

Claim 14

The power driver with short circuit protection of claim 11 and further including a tristate buffer having an input connected to said output of said AND gate and an output connected to said base of said transistor.