Driver circuit for signal transmission and control method of driver circuit

Patent metadata

Field	Value
Publication number	US-9312846-B2
Application number	US-201414280701-A
Country	US
Kind code	B2
Filing date	May 19, 2014
Priority date	Jul 16, 2013
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

A driver circuit for receiving a data input and generating an output signal according to at least the data input is provided. The driver circuit includes a pair of differential output terminals, a current mode drive unit and a voltage mode drive unit. The pair of differential output terminals has a first output terminal and a second output terminal. The current mode drive unit is arranged for outputting a first reference current from one of the first and second output terminals and receiving the first reference current from the other of the first and the second output terminals according to the first data input. The voltage mode drive unit is arranged for coupling a first reference voltage to one of the first and the second output terminals and coupling a second reference voltage to the other of the first and the second output terminals according to the first data input.

First claim

What is claimed is:

1. A driver circuit for receiving a first data input and generating an output signal to a termination element according to at least the first data input, the driver circuit comprising:
a pair of differential output terminals, arranged for outputting the output signal, wherein the pair of differential output terminals has a first output terminal and a second output terminal;
a first current mode drive unit, coupled to the pair of differential output terminals, the first current mode drive unit arranged for generating a first reference current, outputting the first reference current from one of the first output terminal and the second output terminal to the termination element according to the first data input, steering the first reference current to flow into the termination element such that the first reference current outputted from the first current mode drive unit flows through the termination element and is used as at least a portion of a current flowing through the termination element, and receiving the first reference current from the other of the first output terminal and the second output terminal according to the first data input; and
a voltage mode drive unit, coupled to the pair of differential output terminals, the voltage mode drive unit arranged for providing a first reference voltage and a second reference voltage different from the first reference voltage, coupling the first reference voltage to one of the first output terminal and the second output terminal according to the first data input, and coupling the second reference voltage to the other of the first output terminal and the second output terminal according to the first data input.

2. The driver circuit of claim 1 , wherein the first reference voltage is greater than the second reference voltage; and when the first current mode drive unit outputs the first reference current from the first output terminal and receives the first reference current from the second output terminal according to the first data input, the voltage mode drive unit couples the first reference voltage to the first output terminal and couples the second reference voltage to the second output terminal according to the first data input.

3. The driver circuit of claim 1 , wherein a voltage difference between the first output terminal and the second output terminal is a voltage drop across the termination element due to the first reference current flowing through the termination element.

4. The driver circuit of claim 1 , wherein electric potential of one of the first output terminal and the second output terminal is equal to the first reference voltage, and electric potential of the other of the first output terminal and the second output terminal is equal to the second reference voltage.

5. The driver circuit of claim 1 , wherein the first current mode drive unit comprises:
a current source, arranged for generating the first reference current; and
a current sink, arranged for receiving the first reference current, wherein the current source is coupled to one of the first output terminal and the second output terminal according to the first data input, and the current sink is coupled to the other of the first output terminal and the second output terminal according to the first data input.

6. The driver circuit of claim 5 , wherein the first current mode drive unit further comprises:
a first switch, selectively coupled between the current source and the first output terminal according to the first data input;
a second switch, selectively coupled between the current source and the second output terminal according to the first data input;
a third switch, selectively coupled between the current sink and the first output terminal according to the first data input; and
a fourth switch, selectively coupled between the current sink and the second output terminal according to the first data input;

wherein when the first switch and the fourth switch are switched on due to the first data input, the second switch and the third switch are switched off; and when the first switch and the fourth switch are switched off due to the first data input, the second switch and the third switch are switched on.

7. The driver circuit of claim 1 , wherein the voltage mode drive unit further comprises:
a first switch, selectively coupled between the first reference voltage and the first output terminal according to the first data input;
a second switch, selectively coupled between the first reference voltage and the second output terminal according to the first data input;
a third switch, selectively coupled between the second reference voltage and the first output terminal according to the first data input; and
a fourth switch, selectively coupled between the second reference voltage and the second output terminal according to the first data input;

wherein when the first switch and the fourth switch are switched on due to the first data input, the second switch and the third switch are switched off; and when the first switch and the fourth switch are switched off due to the first data input, the second switch and the third switch are switched on.

8. The driver circuit of claim 7 , wherein the voltage mode drive unit comprises:
a first impedance element, wherein one terminal of the first impedance element is coupled to the first output terminal, and another terminal of the first impedance element is coupled to the first reference voltage through the first switch or coupled to the second reference voltage through the third switch according to the first data input; and
a second impedance element, wherein one terminal of the second impedance element is coupled to the second output terminal, and another terminal of the second impedance element is coupled to the first reference voltage through the second switch or coupled to the second reference voltage through the fourth switch according to the first data input;

wherein when the another terminal of the first impedance element is coupled to one of the first reference voltage and the second reference voltage according to the first data input, the another terminal of the second impedance element is coupled to the other of the first reference voltage and the second reference voltage according to the first data input.

9. The driver circuit of claim 7 , wherein the voltage mode drive unit comprises:
a first impedance element, wherein one terminal of the first impedance element is coupled to the first output terminal;
a second impedance element, wherein one terminal of the second impedance element is coupled to the second output terminal, and the first reference voltage is coupled to another terminal of the first impedance element through the first switch or another terminal of the second impedance element through the second switch according to the first data input;
a third impedance element, wherein one terminal of the third impedance element is coupled to the first output terminal;
a fourth impedance element, wherein one terminal of the fourth impedance element is coupled to the second output terminal, and the second reference voltage is coupled to another terminal of the third impedance element through the third switch or another terminal of the fourth impedance element through the fourth switch according to the first data input;

wherein when the first reference voltage is coupled to the another terminal of the first impedance element according to the first data input, the second reference voltage is coupled to the another terminal of the fourth impedance element; and when the first reference voltage is coupled to the another terminal of the second impedance element according to the first data input, the second referen

Assignees

• Mediatek Inc

Inventors

• Wu Chien-Hua
• Luo Yan-Bin

Classifications

• H03K17/16 Primary

  Modifications for eliminating interference voltages or currents · CPC title

• H04L25/0282

  Provision for current-mode coupling · CPC title

• H03K19/018585

  programmable · CPC title

• H04L25/00

  Baseband systems · CPC title

• H04L25/0272

  Arrangements for coupling to multiple lines, e.g. for differential transmission · CPC title