Patent ID: 6664821
Filing Date: 2003-12-16
Classification: H04L

Abstract:
A line driver comprising:a driver output terminal (LB) for connection to a line to be driven; a reference terminal (GND) for connection to a reference voltage; a ramp generator (RG) for providing a substantially linearly inclining and declining ramp signal (RS) in response to a data signal (TXD), the ramp generator (RG) having a control input (CI) for connecting a control signal, the ramp signal (RS) having a slew rate substantially proportional to the control signal; a current source output transistor (T1) having its first main electrode coupled to the reference terminal (GND) and its second main electrode coupled to the driver output terminal (LB) for providing between the driver output terminal (LB) and the reference terminal (GND) a current which is proportional to the ramp signal (RS); a comparator (CMP) for comparing a voltage drop across the current source output transistor (T1) to a threshold voltage; and the comparator (CMP) having an output (T2) coupled to the control input (CI) of the ramp generator (RG) and being operable to increase the slew rate of the ramp signal when the voltage drop is smaller than the threshold voltage.