Driver circuit and method for controlling transition time of a signal
AssigneeMotorola, Inc.
InventorAhmad Baghai Dowlatabadi
Life of this patent
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Abstract
An output driver circuit (10) includes a voltage follower (36) having an input coupled for receiving a reference signal (VREF1) and an output for providing an output signal (VOUT). The output driver circuit (10) further includes an amplifier (28) that compares the voltages of the reference (VREF1) and output (VOUT) signals to generate a compare signal for enabling a conduction path (37). The conduction path (37) alters the voltage of the output signal (VOUT) so that the transition time of the output signal (VOUT) is substantially equal to the transition time of the reference signal (VREF1).
Claims15
A circuit, comprising:
- an amplifier having a first input for receiving a reference voltage, a second input, and an output;
- a voltage follower having an input coupled for receiving the reference voltage and an output coupled to an output of the circuit for providing an output voltage;
- a conduction path coupled between a power supply terminal and the output of the circuit, wherein the output of the amplifier is coupled to the conduction path for controlling the conduction path;
- and
- a feedback path coupled between the output of the circuit and the second input of the amplifier.
A circuit, comprising:
- an amplifier having a first input for receiving a reference voltage and an output;
- a voltage follower having an input coupled for receiving the reference voltage and an output coupled to an output of the circuit for providing an output voltage;
- a conduction path coupled between a power supply terminal and the output of the circuit, wherein the output of the amplifier is coupled to the conduction path for controlling the conduction path;
- and
- a capacitor having a first terminal coupled to the input of the voltage follower and a second terminal coupled for receiving a power supply voltage.
A method for controlling a transition time of a data signal, comprising:
- providing a reference signal;
- comparing a voltage of the reference signal with a voltage of the data signal to enable a conduction path to alter the voltage of the data signal so that the transition time of the data signal is substantially equal to a transition time of the reference signal, and
- generating the data signal using a voltage follower, wherein the voltage of the data signal tracks the voltage of the reference signal, wherein providing the reference signal includes:
- enabling a second conduction path to provide a charging current;
- and
- charging a capacitance with the charging current, wherein the transition time of the reference signal is a function of the charging current and the capacitance.
A circuit, comprising:
- a comparator having a first input coupled to an input of the circuit, a second input coupled to an output of the circuit, and an output;
- a first transistor having a control electrode coupled to the first input of the comparator, a first conduction electrode coupled for receiving a power supply voltage, and a second conduction electrode coupled to the second input of the comparator;
- and
- a second transistor having a control electrode coupled to the output of the comparator, a first conduction electrode coupled for receiving the power supply voltage, and a second conduction electrode coupled to the second input of the comparator.
Dependencies are inferred from the claim text.