Circuit and method for compensating for offset voltage

• US 20060186953A1
• Filed: 04/29/2005
• Published: 08/24/2006
• Est. Priority Date: 02/23/2005
• Status: Active Grant

• Current Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Original Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Inventors: Kwon, Kyoung Soo, Gong, Jung Chul, Hwang, Hyeon Seok, Kim, Sang Suk
• Granted Patent: US 7,227,389 B2
• Time in Patent Office: Days
• US Class Current: 330/9
• CPC Class Codes: H03F 2200/447 the amplifier being protected to temperature influence
• CPC Class Codes: H03F 3/087 with IC amplifier blocks H03F3/085 takes precedence
• CPC Class Codes: H03F 3/45291 Folded cascode stages
• CPC Class Codes: H03F 3/45748 by using a feedback circuit
• CPC Class Codes: H03F 3/45896 by using a feedback circuit
• CPC Class Codes: H03F 3/45973 by using a feedback circuit

Abstract

A circuit for compensating for an offset voltage in a PhotoDetector Integrated Circuit (PDIC). The circuit includes a temperature detection unit, a current transfer unit and a current adjustment unit. The temperature detection unit generates a current that varies with variation in surrounding temperature. The current transfer unit transfers the generated current. The current adjustment unit adjusts the current transferred from the current transfer unit at a predetermined ratio and outputs the adjusted current.

Claims

1. A circuit for compensating for an offset voltage, comprising:

a temperature detection unit generating a current varying with a variation in surrounding temperature;

a current transfer unit transferring the generated current; and

a current adjustment unit adjusting the current transferred from the current transfer unit at a predetermined ratio and outputting the adjusted current.

2. The circuit as set forth in claim 1, wherein the temperature detection unit comprises a transistor having a voltage between a base terminal and an emitter terminal varying with the variation in surrounding temperature.

3. The circuit as set forth in claim 2, wherein the temperature detection unit comprises:

a voltage source providing a constant voltage regardless of the variation in surrounding temperature; and

a resistor connected to the emitter terminal of the transistor.

4. The circuit as set forth in claim 1, wherein the current transfer unit comprises a mirror circuit having two transistors identical in size.

5. The circuit as set forth in claim 1, wherein the current adjustment unit comprises a mirror circuit having two transistors.

6. The circuit as set forth in claim 1, further comprising a voltage adjustment device adjusting a voltage between input and output terminals of the current transfer unit.

7. A circuit for compensating for an offset voltage, comprising:

a temperature detection unit generating a current varying with a variation in surrounding temperature;

a current transfer unit transferring the generated current;

a current adjustment unit amplifying and transferring the current transferred by the current transfer unit; and

an output unit generating a constant current regardless of the variation in surrounding temperature, and outputting a compensated offset voltage by adding the current received from the current adjustment unit to the current generated by the device.

8. The circuit as set forth in claim 7, wherein the temperature detection unit comprises a transistor having a voltage between a base terminal and an emitter terminal varying with the variation in surrounding temperature.

9. The circuit as set forth in claim 8, wherein the temperature detection unit comprises:

a voltage source providing a constant voltage regardless of the variation in surrounding temperature; and

a resistor connected to the emitter terminal of the transistor.

10. The circuit as set forth in claim 7, wherein the current transfer unit comprises a mirror circuit having two transistors identical in size.

11. The circuit as set forth in claim 7, wherein the current adjustment unit comprises a mirror circuit having two transistors.

12. The circuit as set forth in claim 7, further comprising a voltage adjustment device for adjusting a voltage between an input and an output terminal of the current transfer unit.

13. A method for compensating for an offset voltage, comprising the steps of:

generating a current varying with variation in surrounding temperature;

mirroring and transferring the generated current; and

generating a compensation current comprising the steps of;

amplifying the transferred current at a predetermined ratio; and

transferring the compensation current.

14. The method as set forth in claim 13, further comprising the steps of:

adding the compensation current to an offset current generated by an output circuit that generates the offset voltage; and

converting the added current into a voltage to compensate the offset voltage and outputting the converted voltage.

15. The method as set forth in claim 13, wherein the step of mirroring and transferring the generated current further comprises the step of adjusting a driving voltage for the transferred current.