OUTPUT STAGE CIRCUIT FOR OUTPUTTING A DRIVING CURRENT VARYING WITH A PROCESS

• US 20120229174A1
• Filed: 05/03/2011
• Published: 09/13/2012
• Est. Priority Date: 03/08/2011
• Status: Active Grant

• Current Assignee: Etron Technology Inc
• Original Assignee: Etron Technology Inc
• Inventors: Shiah, Chun, Yang, Hao-Jan, Hsu, Ching-Ying
• Granted Patent: US 8,536,903 B2
• Time in Patent Office: Days
• US Class Current: 327/109
• CPC Class Codes: H03K 19/018521 of complementary type, e.g. CMOS
• CPC Class Codes: H03K 19/09482 using a combination of enhancement and depletion transistors

Abstract

An output stage circuit includes a first P-type metal-oxide-semiconductor transistor, a second P-type metal-oxide-semiconductor transistor, an N-type metal-oxide-semiconductor transistor, and a current source. A voltage of a third terminal of the first P-type metal-oxide-semiconductor transistor is a first voltage minus a voltage drop between a first terminal and a second terminal of the first P-type metal-oxide-semiconductor transistor. The N-type metal-oxide-semiconductor transistor is coupled between the third terminal of the first P-type metal-oxide-semiconductor transistor and the current source. A second terminal of the second P-type metal-oxide-semiconductor transistor is coupled to the third terminal of the first P-type metal-oxide-semiconductor transistor. When a second terminal of the N-type metal-oxide-semiconductor transistor receives a kick signal, a driving current flowing through the second P-type metal-oxide-semiconductor transistor is relevant to the voltage of the third terminal of the first P-type metal-oxide-semiconductor transistor.

Claims

1. An output stage circuit for outputting a driving current varying with a process, the output stage circuit comprising:

a first P-type metal-oxide-semiconductor transistor having a first terminal for receiving a first voltage, a second terminal, and a third terminal coupled to the second terminal, wherein a voltage of the third terminal is the first voltage minus a voltage drop between the first terminal and the second terminal of the first P-type metal-oxide-semiconductor transistor;

a second P-type metal-oxide-semiconductor transistor having a first terminal for receiving the first voltage, a second terminal coupled to the third terminal of the first P-type metal-oxide-semiconductor transistor, and a third terminal for outputting an output voltage;

an N-type metal-oxide-semiconductor transistor having a first terminal coupled to the third terminal of the first P-type metal-oxide-semiconductor transistor, a second terminal for receiving a kick signal, and a third terminal; and

a current source coupled between the third terminal of the N-type metal-oxide-semiconductor transistor and ground for providing a constant current.

2. The output stage circuit of claim 1, wherein channel length of the first P-type metal-oxide-semiconductor transistor is equal to channel length of the second P-type metal-oxide-semiconductor transistor.

3. The output stage circuit of claim 1, wherein current flowing through the second P-type metal-oxide-semiconductor transistor corresponds to the voltage drop between the first terminal and the second terminal of the first P-type metal-oxide-semiconductor transistor.

4. The output stage circuit of claim 1, wherein the third terminal of the second P-type metal-oxide-semiconductor transistor is coupled to a feedback circuit and/or a load.

5. The output stage circuit of claim 1, wherein the first terminal of the first P-type metal-oxide-semiconductor transistor is a source terminal, the second terminal of the first P-type metal-oxide-semiconductor transistor is a gate terminal, and the third terminal of the first P-type metal-oxide-semiconductor transistor is a drain terminal.

6. The output stage circuit of claim 1, wherein the first terminal of the second P-type metal-oxide-semiconductor transistor is a source terminal, the second terminal of the second P-type metal-oxide-semiconductor transistor is a gate terminal, and the third terminal of the second P-type metal-oxide-semiconductor transistor is a drain terminal.

7. The output stage circuit of claim 1, wherein the first terminal of the N-type metal-oxide-semiconductor transistor is a drain terminal, the second terminal of the N-type metal-oxide-semiconductor transistor is a gate terminal, and the third terminal of the N-type metal-oxide-semiconductor transistor is a source terminal.

8. An output stage circuit for outputting a driving current varying with a process, the output stage circuit comprising:

an N-type metal-oxide-semiconductor transistor having a first terminal for receiving a first voltage, a second terminal coupled to the first terminal, and a third terminal, wherein a voltage of the third terminal is the first voltage minus a voltage drop between the second terminal and the third terminal of the N-type metal-oxide-semiconductor transistor;

a first P-type metal-oxide-semiconductor transistor having a first terminal for receiving the first voltage, a second terminal coupled to the third terminal of the N-type metal-oxide-semiconductor transistor, and a third terminal for outputting an output voltage;

a second P-type metal-oxide-semiconductor transistor having a first terminal coupled to the third terminal of the N-type metal-oxide-semiconductor transistor, a second terminal for receiving a kick signal, and a third terminal; and

a current source coupled between the third terminal of the second P-type metal-oxide-semiconductor transistor and ground for providing a constant current.

9. The output stage circuit of claim 8, wherein channel length of the N-type metal-oxide-semiconductor transistor is equal to channel length of the first P-type metal-oxide-semiconductor transistor.

10. The output stage circuit of claim 8, wherein current flowing through the first P-type metal-oxide-semiconductor transistor corresponds to the voltage drop between the second terminal and the third terminal of the N-type metal-oxide-semiconductor transistor.

11. The output stage circuit of claim 8, wherein the third terminal of the first P-type metal-oxide-semiconductor transistor is coupled to a feedback circuit and/or a load.

12. The output stage circuit of claim 8, wherein the first terminal of the N-type metal-oxide-semiconductor transistor is a drain terminal, the second terminal of the N-type metal-oxide-semiconductor transistor is a gate terminal, and the third terminal of the N-type metal-oxide-semiconductor transistor is a source terminal.

13. The output stage circuit of claim 8, wherein the first terminal of the first P-type metal-oxide-semiconductor transistor is a source terminal, the second terminal of the first P-type metal-oxide-semiconductor transistor is a gate terminal, and the third terminal of the first P-type metal-oxide-semiconductor transistor is a drain terminal.

14. The output stage circuit of claim 8, wherein the first terminal of the second P-type metal-oxide-semiconductor transistor is a source terminal, the second terminal of the second P-type metal-oxide-semiconductor transistor is a gate terminal, and the third terminal of the second P-type metal-oxide-semiconductor transistor is a drain terminal.