Patent ID: 6031389
Filing Date: 2000-02-29
Classification: H03K

Abstract:
An output driver circuit having an input and an output, comprising:a fixed pull-up transistor coupled to a fixed pull-down transistor, said fixed pull-up and pull-down transistors having gate terminals coupled to the input and common source/drain terminals coupled to the output;a charge-up current source, and a charge-down current source;a first current steering circuit coupled to the charge-up current source for charging up a capacitor coupled to said gate terminals of said fixed pull-up and pull-down transistors in response to a signal on the input;a second current steering circuit coupled to the charge-down current source for discharging said capacitor in response to said signal on the input;a switched pull-up transistor coupled in parallel to said fixed pull-up transistor;a switched pull-down transistor coupled in parallel to said fixed pull-down transistor; andvoltage level detect circuitry coupled to said switched pull-up and switched pull-down transistors, for selectively turning on said switched pull-up or pull-down transistors after a signal at the output crosses a predetermined level.