Dual threshold differential discriminator

A high-side transistor driver, comprising:

• a logic block having a first through a fourth signal input and a first and a second signal output;
• an under-voltage lockout for disabling said second signal output during an undervoltage condition as detected by an undervoltage detection means coupled to a power input;
• an output driver for driving the gate of a high-side transistor connected to a load;
• a flip-flop for receiving said first and second signal outputs of the logic block and for switching the output driver on and off wherein said load is thereby controlled;
• a first through a fourth constant current source;
• and
• a first through a fourth transistor respectively connected at their sources to each of the first through fourth constant current sources and said first through fourth signal inputs to the logic block with the gates of the first and second transistors connected to a first control input and the gates of the third and fourth transistors connected to a second control input, wherein the logic block is responsive to a pair of signals on said first and second control inputs where one is less than a first threshold voltage and the other exceeds a second threshold voltage, different from said first threshold voltage, and wherein if said pair of signals on either or both of said first and second control are between said first and second threshold voltages, or are both less than said first threshold voltage or are both more than said second threshold voltage, then the logic block is such that a change of state of the flip-flop is prevented.