Current mirror with low static current and transconductance amplifier thereof

• US 7,227,416 B2
• Filed: 03/10/2005
• Issued: 06/05/2007
• Est. Priority Date: 12/15/2004
• Status: Expired due to Fees

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Liu, Chia-Chun, Lou, Chih-Hong
• Primary Examiner(s): Pascal; Robert
• Assistant Examiner(s): Hieu; Nguyen
• Application Number:
  US11/075,655
• Publication Number:
  US 20060125566A1
• Time in Patent Office: 817 Days
• Field of Search: 330/288, 323315-316
• US Class Current: 330/288
• CPC Class Codes: G05F 3/262 using field-effect transistors only
• CPC Class Codes: H03F 2203/45096 the difference of two signals being made by, e.g. combining two or more current mirrors, e.g. differential current mirror
• CPC Class Codes: H03F 2203/45288 Differential amplifier with circuit arrangements to enhance the transconductance
• CPC Class Codes: H03F 2203/45521 the FBC comprising op amp stages, e.g. cascaded stages of the dif amp and being coupled between the LC and the IC
• CPC Class Codes: H03F 3/45273 Mirror types
• CPC Class Codes: H03F 3/45475 using IC blocks as the active amplifying circuit

Abstract

A current mirror with a transconductance amplifier containing the current mirror with a low static current. The current mirror includes: a load with first end and a second end, the first end coupling to a first input current and a fixed voltage difference existing between the first and second ends; a first transistor, whose drain is coupled to the second end of the load, whose gate is coupled to the first end of the load, and whose source is coupled to a second input current; and a second transistor, whose drain is coupled to a third port and an output current, whose gate is coupled to the second end of the load, and whose source is coupled to the ground. The transconductance amplifier contains: a voltage amplifier stage, a transconductance stage, and a current amplifier stage for amplifying the current and containing the current mirror.

Claims

1. A current mirror with a low static current for amplifying the difference between a first input current and a second input current into an output current, comprising:

a load, which has a first end coupling to the first input current and a second end with a fixed voltage difference imposed in between;

a first transistor, whose drain is coupled to the second end of the load, whose gate is coupled to the first end of the load, and whose source is coupled to the second input current;

a second transistor, whose drain is coupled to a second port, whose gate is coupled to the second end of the load, and whose source is coupled to the ground; and

a third transistor, whose drain is coupled to a third port and the output current, whose gate is coupled to the second end of the load, and whose source is coupled to the ground.

2. The current mirror of claim 1, wherein the load includes a tunable resistor whose resistance is adjusted according to the bias current to provide a fixed voltage difference.

3. The current mirror of claim 2, wherein the tunable resistor is a metal oxide semiconductor (MOS) operating in the linear region of the semiconductor.

4. A transconductance amplifier comprising:

a voltage amplifier stage for amplifying a voltage;

a transconductance stage coupled to the voltage amplifier stage for converting the voltage into a current; and

a current amplifier stage coupled to the transconductance stage and containing a current mirror with a low static current for amplifying the difference between a first input current and a second input current, the current mirror including;

a load, which has a first end coupling to the first input current and a second end with a fixed voltage difference imposed in between;

a first transistor, whose drain is coupled to the second end of the load, whose gate is coupled to the first end of the load, and whose source is coupled to the second input current;

a second transistor, whose drain is coupled to a second port, whose gate is coupled to the second end of the load, and whose source is coupled to the ground; and

a third transistor, whose drain is coupled to a third port and the output current, whose gate is coupled to the second end of the load, and whose source is coupled to the ground.

5. The transconductance amplifier of claim 4, wherein the load includes a tunable resistor whose resistance is adjusted according to the bias current to provide a fixed voltage difference.

6. The transconductance amplifier of claim 5, wherein the tunable resistor is a metal oxide semiconductor (MOS) operating in the linear region of the semiconductor.