Abstract
The present invention relates to an inhibitable switching circuit, and in particular to a switching circuit comprising a back to back diode switch. The inhibitable switching circuit of the present invention has particular application in the construction of logic gates. The concept of a rapidly switching diode switch comprising a pair of diodes connected back to back (i.e. either cathodes connected together or anodes connected together) was first disclosed by D P Neville in British patent GB1417839. D P Neville was the first to realise that by applying a pulsed input signal to such a back to back diode switch, which is pulsed very rapidly with a pulse duration shorter than the storage or delay times of the diodes, an equally rapidly switching output can be obtained which follows the input signal. D P Neville realised that this switching action could be explained by applying an electrostatic model to the behaviour of the diodes as is discussed in detail in GB1417839 to which reference should be made. D P Neville applied his invention to the construction of logic gates capable of extremely rapid switching and with lower power consumption (the switch is in fact powered by the input signal). In addition to the logic gates proposed by D P Neville, back to back series connected diodes have been used with beneficial effects in other applications. For example, in Motorola Semiconductor Products Inc., ?The Effect of Emitter-Base Avalanching on High-Voltage Power Switching Transistors?, Application Note AN-80, 1981, MotorolaTM placed the base-emitter junction of a power transistor under reverse bias during turn-off, causing it to go into breakdown and decrease its turn-off losses. By taking the junction into avalanche breakdown, large charge build-ups are removed very quickly, therefore reducing turn-off losses. In PCT application number PCT/GB87/00790 (publication number WO88/03726), Emco Display Technology Limited utilise a pair of back to back diodes to enhance the rising and falling edges of signals.
Original language | English |
---|---|
Patent number | PCT/GB2004/002771 (GB0315979.5), Filed 28 June 2004, Publication No: W02005/00653, Publication date 20 Jan 2005 |
Publication status | Published - 2 Jan 2005 |