Dynamic integration time adjustment of a clocked data sampler using a static analog calibration circuit

• US 10,680,634 B1
• Filed: 04/08/2019
• Issued: 06/09/2020
• Est. Priority Date: 04/08/2019
• Status: Active Grant

• Current Assignee: Kandou Labs, SA
• Original Assignee: Kandou Labs, SA
• Inventors: Gharibdoust, Kiarash, Tajalli, Armin, Jampani, Pavan Kumar, Hormati, Ali
• Primary Examiner(s): Nguyen, Khai M
• Application Number:
  US16/378,467
• Time in Patent Office: 428 Days
• Field of Search: 341120, 341164
• CPC Class Codes: H03K 19/00369 Modifications for compensating variations of temperature, supply voltage or other physical parameters
• CPC Class Codes: H03M 1/069 by range overlap between successive stages or steps
• CPC Class Codes: H03M 1/1004 without interrupting normal operation, e.g. by providing an additional component for temporarily replacing components to be tested or calibrated H03M1/1009, H03M1/1071 take precedence
• CPC Class Codes: H03M 1/1009 Calibration
• CPC Class Codes: H03M 1/1215 using time-division multiplexing
• CPC Class Codes: H03M 1/1245 Details of sampling arrangements or methods
• CPC Class Codes: H03M 1/365 the voltage divider being a single resistor string

Abstract

Methods and systems are described for generating a process-voltage-temperature (PVT)-dependent reference voltage at a reference branch circuit based on a reference current obtained via a band gap generator and a common mode voltage input, generating a PVT-dependent output voltage at an output of a static analog calibration circuit responsive to the common mode voltage input and an adjustable current, adjusting the adjustable current through the static analog calibration circuit according to a control signal generated responsive to comparisons of the PVT-dependent output voltage to the PVT-dependent reference voltage, and configuring a clocked data sampler with a PVT-calibrated current by providing the control signal to the clocked data sampler.

Claims

1. An apparatus comprising:

a reference branch circuit configured to generate a process-voltage-temperature (PVT)-dependent reference voltage based on a reference current obtained via a band gap generator and a common mode voltage input;

a static analog calibration circuit configured to generate a PVT-dependent output voltage responsive to the common mode voltage input and an adjustable current;

a control signal generator configured to compare the PVT-dependent output voltage to the PVT-dependent reference voltage and to responsively generate a control signal for adjusting the adjustable current through the static analog calibration circuit, the control signal configuring a clocked data sampler with a PVT-calibrated current.

2. The apparatus of claim 1, wherein the control signal generator is configured to adjust the adjustable current until the PVT-dependent output voltage is equal to the PVT-dependent reference voltage.

3. The apparatus of claim 1, wherein the reference branch circuit is a replica of a branch circuit in the static analog calibration circuit.

4. The apparatus of claim 1, wherein the static analog calibration circuit and the reference branch circuit each comprise enabling transistors, and wherein the enabling transistors are selectively enabled to calibrate the PVT-calibrated current.

5. The apparatus of claim 4, wherein the enabling transistors are selectively enabled responsive to a change in temperature.

6. The apparatus of claim 4, wherein the enabling transistors are selectively enabled responsive to a change in common mode input voltage.

7. The apparatus of claim 1, wherein the control signal generator comprises an accumulator configured to accumulate comparisons between the PVT-dependent output voltage and the PVT-dependent reference voltage.

8. The apparatus of claim 7, wherein the accumulator is a digital accumulator.

9. The apparatus of claim 7, wherein the control signal generator comprises a chopper amplifier configured to generate the comparisons between the PVT-dependent output voltage and the PVT-dependent reference voltage.

10. The apparatus of claim 1, wherein the common mode voltage input is obtained via a resistor-capacitor network connected to a variable gain amplifier (VGA) operating on an information signal processed by the clocked data sampler.

11. A method comprising:

generating a process-voltage-temperature (PVT)-dependent reference voltage at a reference branch circuit based on a reference current obtained via a band gap generator and a common mode voltage input;

generating a PVT-dependent output voltage at an output of a static analog calibration circuit responsive to the common mode voltage input and an adjustable current;

adjusting the adjustable current through the static analog calibration circuit according to a control signal generated responsive to comparisons of the PVT-dependent output voltage to the PVT-dependent reference voltage; and

configuring a clocked data sampler with a PVT-calibrated current by providing the control signal to the clocked data sampler.

12. The method of claim 11, wherein the adjustable current is adjusted until the PVT-dependent output voltage is equal to the PVT-dependent reference voltage.

13. The method of claim 11, wherein the reference branch circuit is a replica of a branch circuit in the static analog calibration circuit.

14. The method of claim 11, further comprising enabling the static analog calibration circuit and the reference branch circuit via enabling transistors to calibrate the PVT-calibrated current.

15. The method of claim 14, wherein the static analog calibration circuit and the reference branch circuit are enabled responsive to a change in temperature.

16. The method of claim 14, wherein the static analog calibration circuit and the reference branch circuit are enabled responsive to a change in common mode input voltage.

17. The method of claim 11, wherein the comparisons between the PVT-dependent output voltage and the PVT-dependent reference voltage are accumulated in an accumulator circuit.

18. The method of claim 17, wherein the comparisons between the PVT-dependent output voltage and the PVT-dependent reference voltage are generated using a chopper amplifier.

19. The method of claim 11, further comprising obtaining the common mode voltage input via a resistor-capacitor network connected to a variable gain amplifier (VGA) operating on an information signal processed by the clocked data sampler.

20. The method of claim 11, wherein the adjustable current through the static analog calibration circuit is twice a magnitude as the reference current.