BAND-GAP REFERENCE VOLTAGE GENERATOR FOR LOW-VOLTAGE OPERATION AND HIGH PRECISION

• US 20090128230A1
• Filed: 08/20/2008
• Published: 05/21/2009
• Est. Priority Date: 11/15/2007
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute, Industry-University Cooperation Foundation Hanyang University
• Original Assignee: Electronics and Telecommunications Research Institute, Industry-University Cooperation Foundation Hanyang University
• Inventors: Kim, Hyoung-Joong, Kwon, Jong Kee, Kim, Yi Gyeong, Roh, Jeong Jin, Roh, Hyung Dong
• Granted Patent: US 7,692,481 B2
• Time in Patent Office: Days
• US Class Current: 327/539
• CPC Class Codes: G05F 3/30 Regulators using the difference between the base-emitter voltages of two bipolar transistors operating at different current densities G05F3/26 takes precedence

Abstract

Provided is a band-gap reference voltage generator for low-voltage operation and high precision. The band-gap reference voltage generator minimizes voltage drop by connecting resistors in parallel to bipolar transistors, and cancels temperature dependence by properly adjusting a resistor of an output stage, so that it can provide a stable reference voltage that is unaffected by a change in temperature in spite of a low power supply voltage. Further, the band-gap reference voltage generator minimizes variation of the reference voltage caused by offset noise by switching of input and output voltages at input and output stages of a feedback amplifier, so that it can provide a precise reference voltage.

Claims

1. A band-gap reference voltage generator for low-voltage operation and high precision, comprising:

first through third p-channel metal oxide semiconductor (PMOS) transistors, gates and sources of which are connected to a first node and a power supply terminal respectively, drains of which are connected to second, third and fourth nodes respectively, and which are configured as current mirrors;

a feedback amplifier, which includes fourth and fifth PMOS transistors configured as current mirrors and sixth and seventh n-channel metal oxide semiconductor (NMOS) transistors, wherein non-inverting and inverting input voltages are input to gates of the sixth and seventh NMOS transistors respectively, and non-inverting and inverting output voltages are output from drains of the fourth and fifth PMOS transistors respectively;

a first resistor, which is connected between the second node and a fifth node;

second, third and fourth resistors, which are connected between the second, third and fourth nodes and ground, respectively;

a first bipolar transistor, which is connected with the second resistor in parallel, an emitter of which is connected to the fifth node, and a collector and a base of which are grounded; and

a second bipolar transistor, which is connected with the third resistor in parallel, an emitter of which is connected to the third node, and a collector and a base of which are grounded,

wherein voltage between the fourth node and the ground is used as reference voltage.

2. The band-gap reference voltage generator according to claim 1, wherein the reference voltage has a value between 0V and 1V.

3. The band-gap reference voltage generator according to claim 1, wherein the fourth resistor is adjusted for resistance such that the reference voltage is unaffected by a change in temperature.

4. The band-gap reference voltage generator according to claim 1, wherein the fourth and fifth PMOS transistors have sources connected to the power supply terminal in common, gates connected to each other, and drains connected to drains of the sixth and seventh NMOS transistors respectively.

5. The band-gap reference voltage generator according to claim 1, further comprising:

a first voltage modulator, which is connected to the gates of the sixth and seventh NMOS transistors, and crosses and modulates the non-inverting and inverting input voltages;

a second voltage modulator, which is connected to the drains of the fourth and fifth PMOS transistors, and crosses and modulates the non-inverting and inverting output voltages; and

a low-pass filter, which is connected between the fourth node and the ground, and passes low-frequency signals of voltage of the fourth node.

6. The band-gap reference voltage generator according to claim 5, wherein the first voltage modulator comprises:

eighth and ninth PMOS transistors having gates to which first and second clocks are applied, and which are configured as switches; and

tenth and eleventh PMOS transistors having gates to which the first and second clocks are applied, and which are configured as switches; and

sources of the eighth and ninth PMOS transistors and drains of the tenth and eleventh PMOS transistors are connected to the gates of the sixth and seventh NMOS transistors in common.

7. The band-gap reference voltage generator according to claim 5, wherein the second voltage modulator comprises:

twelfth and thirteenth PMOS transistors having gates to which first and second clocks are applied, and which are configured as switches; and

fourteenth and fifteenth PMOS transistors having gates to which the first and second clocks are applied, and which are configured as switches; and

drains of the twelfth and thirteenth PMOS transistors and sources of the fourteenth and fifteenth PMOS transistors are connected to the drains of the fourth and fifth PMOS transistors in common.

8. The band-gap reference voltage generator according to claim 6, wherein the first voltage modulator crosses the non-inverting and inverting input voltages to cause frequencies of the non-inverting and inverting input voltages to be modulated into odd harmonics of frequencies of the first and second clocks.

9. The band-gap reference voltage generator according to claim 7, wherein the second voltage modulator crosses the non-inverting and inverting output voltages to cause frequencies of the non-inverting and inverting output voltages to be restored to the frequencies of the non-inverting and inverting input voltages.

10. The band-gap reference voltage generator according to claim 9, wherein the second voltage modulator crosses the non-inverting and inverting offset voltages of the feedback amplifier to cause the frequencies of the non-inverting and inverting offset voltages to be modulated into the odd harmonics of the first and second clock frequencies.

11. The band-gap reference voltage generator according to claim 10, wherein the non-inverting and inverting offset voltages, which are modulated into the odd harmonics of the first and second clock frequencies, are filtered by the low-pass filter.

12. The band-gap reference voltage generator according to claim 5, wherein the low-pass filter is adapted so that a capacitor is connected to the fourth resistor in parallel.

13. The band-gap reference voltage generator according to claim 1, further comprising a sixteenth NMOS transistor, to a gate of which bias voltage is applied, wherein the sixteenth NMOS transistor has a drain connected to sources of the sixth and seventh NMOS transistors, and a source connected to the ground.