HYSTERETIC POWER CONVERTER WITH CALIBRATION CIRCUIT

• US 20120133345A1
• Filed: 11/30/2010
• Published: 05/31/2012
• Est. Priority Date: 11/30/2010
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: ROTH, Alan, SOENEN, Eric, TAI, Chia-Liang
• Granted Patent: US 9,143,033 B2
• Time in Patent Office: Days
• US Class Current: 323/282
• CPC Class Codes: G01R 1/203 Resistors used for electric measuring, e.g. decade resistors standards, resistors for comparators, series resistors, shunts resistors in general H01C; microwave or radiowave terminations H01P1/26; coupling devices H01R
• CPC Class Codes: G05F 1/00 Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
• CPC Class Codes: G05F 1/10 Regulating voltage or current G05F1/02 takes precedence; for electric railways B60M3/02
• CPC Class Codes: G05F 1/40 using discharge tubes or semiconductor devices as final control devices
• CPC Class Codes: G05F 1/56 using semiconductor devices in series with the load as final control devices G05F1/461 takes precedence
• CPC Class Codes: G05F 1/575 characterised by the feedback circuit
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators

Abstract

A hysteretic power converter includes a comparator, a calibration circuit, and an output node having an output voltage. The calibration circuit is configured to supply a calibrated voltage to the comparator. The comparator controls the output voltage based on the calibrated voltage and a feedback voltage representing at least a portion of the output voltage.

Claims

1. A hysteretic power converter, comprising:

a first comparator;

a calibration circuit, and

an output node arranged to have an output voltage;

wherein the calibration circuit is configured to supply a calibrated voltage to the first comparator, and the first comparator controls the output voltage based on the calibrated voltage and a feedback voltage representing at least a portion of the output voltage.

2. The hysteretic power converter of claim 1, wherein the calibration circuit comprises:

a second comparator configured to receive the feedback voltage, compare the feedback voltage with a first reference voltage, and provide a calibration comparator output; and

a charge pump,

wherein the calibration comparator output is arranged to control the charge pump, and the charge pump is configured to supply the calibrated voltage.

3. The hysteretic power converter of claim 2, wherein the calibration circuit further comprises a voltage divider configured to divide an output voltage from the charge pump and to supply a divided output voltage as the calibrated voltage.

4. The hysteretic power converter of claim 2, wherein the calibration circuit further comprises a voltage clamp configured to limit the calibrated voltage.

5. The hysteretic power converter of claim 2, wherein the calibration circuit further comprises a low pass filter configured to average the feedback voltage.

6. The hysteretic power converter of claim 2, wherein the charge pump comprises at least a switch and at least a current source.

7. The hysteretic power converter of claim 2, further comprising a third comparator that is configured to receive a second reference voltage and control the output voltage together with the first comparator based on the calibrated voltage, the feedback voltage, and the second reference voltage.

8. The hysteretic power converter of claim 7, further comprising two latches coupled to the first comparator and the third comparator.

9. The hysteretic power converter of claim 1, wherein the hysteretic power converter comprises a buck converter.

10. The hysteretic power converter of claim 1, wherein the hysteretic power converter comprises a boost converter.

11. A method of controlling a hysteretic power converter, comprising:

supplying a feedback voltage representing at least a portion of an output voltage of the hysteretic power converter to a calibration circuit;

the calibration circuit supplying a calibrated voltage to a first comparator in the hysteretic power converter; and

the first comparator controlling the output voltage based on the calibrated voltage and the at least a portion of the output voltage.

12. The method of claim 11, further comprising:

a second comparator in the calibration circuit receiving the feedback voltage;

the second comparator comparing the feedback voltage to a reference voltage; and

supplying a calibration comparator output voltage.

13. The method of claim 12, further comprising:

controlling a charge pump in the calibration circuit according to the calibration comparator output voltage; and

the charge pump supplying a charge pump voltage for the calibrated voltage.

14. The method of claim 13, further comprising:

a voltage divider in the calibration circuit dividing the charge pump voltage; and

supplying a divided charge pump voltage as the calibrated voltage.

15. The method of claim 11, further comprising a voltage clamp in the calibration circuit limiting the calibrated voltage.

16. The method of claim 11, further comprising a low pass filter in the calibration circuit averaging the at least a portion of the output voltage.

17. The method of claim 11, further comprising:

a second comparator receiving a reference voltage; and

the second comparator and the first comparator controlling the output voltage based on the calibrated voltage, the feedback voltage, and the reference voltage.

18. An integrated circuit including a hysteretic power converter, the hysteretic power converter comprising:

an output node arranged to have an output voltage;

a first comparator arranged to receive a feedback voltage representing at least a portion of the output voltage;

a switch coupled to an output of the first comparator; and

a calibration circuit including;

a second comparator configured to receive the feedback voltage, compare the feedback voltage to a reference voltage, and provide a calibration comparator output voltage; and

a charge pump configured to supply a charge pump voltage that is controlled by the second comparator according to the calibration comparator output voltage;

wherein the feedback voltage is arranged to be coupled to the calibration circuit, the calibration circuit is configured to supply a calibrated voltage from the charge pump voltage to the first comparator, and the first comparator controls the switch based on the calibrated voltage and the feedback voltage.

19. The integrated circuit of claim 18, wherein the calibration circuit further comprises a voltage divider configured to divide the charge pump voltage and supply a divided charge pump voltage as the calibrated voltage, and a voltage clamp configured to limit the calibrated voltage.

20. The integrated circuit of claim 18, wherein the calibration circuit further comprises a low pass filter configured to average the feedback voltage.