Patent ID: 6100712
Filing Date: 2000-08-08
Classification: H03K

Abstract:
A driver circuit connected between a first supply terminal and second, lower supply terminal for driving a load, said driver comprisingan input node for receiving an input signal and an output node for connection to the load;a pull down switch having a control terminal and a current channel coupled between the output node and the second, lower supply terminal, said control terminal being coupled to said input node and rendering said current channel conductive to discharge said output node in response to a selected signal at said input node;a current sink circuit controlling said pull down switch to discharge the output node in response to a selected voltage at said output node, said current sink circuit including (i) a feeder switch having a control input and a current channel coupling the first supply to said control terminal of said pull down switch, (ii) a first charging path coupling the first supply to said control terminal of said feeder switch in response to receipt of the selected signal at said input node, and (iii) a discharge circuit which discharges said control terminal of said feeder switch when the voltage at the output node is equal to or less than a first value,characterized in that:said first charging path has a first impedance by which it takes a first time period after receipt of the selected signal at said input node to charge said control terminal of said feeder switch to a threshold which renders said feeder switch conductive, andsaid driver circuit further comprising an auxiliary charging path coupling the first supply to the control gate of said feeder switch in response to the selected signal at said input node, said second current path having a lower impedance than said first charging path and charging said control terminal of said feeder switch to the threshold in a time period shorter than said first time period.