Granted Patent B1

US 8,723,595 · App. 13/769,830 · Granted May 13, 2014

Abstract

Claims (37)

1. A voltage generator, comprising:

a first current source, generating a first current and a second current according to a first bias voltage, and the second current being provided to a common end, and the first and second currents having a first temperature coefficient;

a second current source, generating a third current and a fourth current according to a second bias voltage, and the third and fourth currents having a second temperature coefficient;

a first resistor, having a first and second ends, the first end being coupled to the first current source for receiving the first current, the first resistor generating an output voltage on the first end;

a reference voltage generator, providing a first reference voltage and a second reference voltage according to the first and third currents;

a first amplifier, coupled to the reference voltage generator and the first current source, the first amplifier generating the first bias voltage according to the first and second reference voltages;

a second resistor, coupled between the second current source and the reference ground, the second resistor receiving the second current source for generating a third reference voltage; and

a second amplifier, coupled to the reference voltage generator and the second current source, the second amplifier generating the second bias voltage according to the second and third reference voltages,

wherein, the first temperature coefficient and the second temperature coefficient are complementary.

2. The voltage generator according to claim 1 , wherein the first current source comprises:

a first transistor, having a first end, a second end, and a control end, wherein the first end of the first transistor is coupled to a reference power, the control end of the first transistor receives the first bias voltage, and the second end of the first transistor generates the first current; and

a second transistor, having a first end, a second end, and a control end, wherein the first end of the second transistor is coupled to the reference power, the control end of the second transistor receives the first bias voltage, and the second end of the second transistor is coupled to the common end.

3. The voltage generator according to claim 1 , wherein the second current source comprises:

a first transistor, having a first end, a second end, and a control end, wherein the first end of the first transistor is coupled to a reference power, the control end of the first transistor receives the second bias voltage, and the second end of the first transistor generates the third current; and

a second transistor, having a first end, a second end, and a control end, wherein the first end of the second transistor is coupled to the reference power, the control end of the second transistor receives the second bias voltage, and the second end of the second transistor generates the fourth current.

4. The voltage generator according to claim 1 , wherein the reference voltage generator comprises:

a third resistor, coupled between the common end and a first input end of the first amplifier;

a fourth resistor, coupled between the common end and a second input end of the first amplifier;

a fifth resistor, having a first end and a second end, wherein the first end of the fifth resistor is coupled to the second input end of the first amplifier;

a first diode, wherein an anode of the first diode is coupled to the first input end of the amplifier, a cathode of the first diode is coupled to the reference ground; and

a second diode, an anode of the second diode is coupled to the second end of the fifth resistor, a cathode of the second diode is coupled to the reference ground.

5. The voltage generator according to claim 4 , wherein the first diode is a first transistor, and the second diode is a second transistor, the first transistor has a first end, a second end and a control end, the second end and the control end of the first transistor are coupled to the reference ground, the first end of the second transistor is coupled to the first input end of the first amplifier, the second transistor has a first end, a second end and a control end, the second end and the control end of the second transistor are coupled to the reference ground, the first end of the first transistor is coupled to the second end of the fifth resistor.

6. The voltage generator according to claim 1 , further comprising:

a chopper, coupled between the first amplifier and the reference voltage generator.

7. The voltage generator according to claim 6 , wherein the chopper comprises:

a first switch, wherein a first end of the first switch receives the first reference voltage, a second end of the first switch is coupled to a first input end of the first amplifier, and the first switch is controlled by a clock signal;

a second switch, a first end of the second switch receives the first reference voltage, a second end of the second switch is coupled to a second input end of the first amplifier, and the second switch is controlled by a inversed clock signal;

a third switch, a first end of the third switch receives the second reference voltage, a second end of the third switch is coupled to the first input end of the first amplifier, and the third switch is controlled by the inversed clock signal; and

a fourth switch, a first end of the fourth switch receives the second reference voltage, a second end of the fourth switch is coupled to the second input end of the first amplifier, and the fourth switch is controlled by the clock signal.

8. The voltage generator according to claim 1 , further comprising:

a chopper, coupled between the second amplifier and the reference voltage generator.

9. The voltage generator according to claim 8 , wherein the chopper comprises:

a first switch, wherein a first end of the first switch receives the second reference voltage, a second end of the first switch is coupled to a first input end of the second amplifier, and the first switch is controlled by a clock signal;

a second switch, a first end of the second switch receives the second reference voltage, a second end of the second switch is coupled to a second input end of the second amplifier, and the second switch is controlled by a inversed clock signal;

a third switch, a first end of the third switch is coupled to the second resistor and the second current source, a second end of the third switch is coupled to the first input end of the second amplifier, and the third switch is controlled by the inversed clock signal; and

a fourth switch, a first end of the fourth switch is coupled to the second resistor and the second current source, a second end of the fourth switch is coupled to the second input end of the second amplifier, and the fourth switch is controlled by the clock signal.

10. The voltage generator according to claim 1 , wherein each of the first and the second amplifiers has a chopper output stage.

Assignments (17)