TTL logic driver circuit

A bootstrap logic driver circuit having first and second output voltage conditions responsive to respective first and second input conditions and operable from a power supply having high (positive) and low (negative) voltage outputs, the circuit including a first bipolar transistor coupled between high and low voltage supplies and having a collector load comprising a first diode structure constituted by second and third bipolar transistors, a fourth bipolar transistor coupled between the voltage supplies and having a collector load comprising a second diode structure constituted by a fifth bipolar transistor and a resistor connected in series therewith, a sixth bipolar transistor comprising an emitter follower output stage coupled to the collector of the fourth transistor, and a bootstrap capacitor coupled between said first and second diode structures and being arranged to store charge during the first output condition of the circuit so as to provide during the second output condition a voltage higher than said high voltage at its connection with the second diode structure and at the collector of the fourth transistor so as to drive said emitter follower output transistor between first and second output conditions.

A method of generating a bootstrapped output in a logic driver circuit having first and second output voltage conditions responsive to respective first and second input conditions and operable from a power supply having high (positive) and low (negative) voltage outputs, said circuit including a first bipolar transistor coupled between high and low voltage supplies and having a collector load comprising a first diode structure, a second bipolar transistor coupled between the voltage supplies and having a collector load comprising a second diode structure, and a bootstrap capacitor coupled between said first and second diode structures, wherein the method comprises charging said bootstrap capacitor when the circuit is in its first condition, and discharging the bootstrap capacitor when the circuit is in its second condition so as to generate a voltage higher than said high voltage.