Comparator architecture and related methods

• US 10,536,143 B1
• Filed: 09/13/2019
• Issued: 01/14/2020
• Est. Priority Date: 05/31/2018
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Price, Burt Lee, Shah, Dhaval
• Primary Examiner(s): Hiltunen, Thomas J.
• Application Number:
  US16/570,173
• Publication Number:
  US 20200007121A1
• Time in Patent Office: 123 Days
• CPC Class Codes: G01R 19/16576 comparing DC or AC voltage with one threshold G01R19/16514, G01R19/16519, G01R19/16528, G01R19/16533 and G01R19/1659 take precedence
• CPC Class Codes: G06F 1/24 Resetting means
• CPC Class Codes: H03F 1/0211 with control of the supply voltage or current
• CPC Class Codes: H03K 17/22 Modifications for ensuring a predetermined initial state when the supply voltage has been applied bi-stable generators H03K3/12
• CPC Class Codes: H03K 17/223 in field-effect transistor switches
• CPC Class Codes: H03K 17/284 in field effect transistor switches
• CPC Class Codes: H03K 5/2472 using field effect transistors H03K5/2436 takes precedence

Abstract

A system is disclosed. The system includes a first stage configured to receive V_IN and V_REF, the first stage including an input transistor pair, wherein the input voltage is coupled to the input transistor pair, the input transistor pair is coupled to ground, and the input transistor pair includes at a common drain a high-gain node having a voltage V_HGN. The system further include a second stage coupled to the high-gain node and configured to generate V_OUT based on a difference between V_IN and V_REF, the second stage comprising a resistor and an inverter transistor pair, wherein the gates of the inverter transistor pair are coupled to the high-gain node of the first stage and the resistor couples the high-gain node of first stage to a common drain of the inverter transistor pair and is configured to provide and/or draw current to and/or from the high-gain node of first stage.

Claims

1. A circuit comprising:

a first stage configured to receive an input voltage and a reference voltage, the first stage comprising a reference transistor pair and a clamp transistor, wherein;

the reference voltage is coupled to the reference transistor pair;

the reference transistor pair is coupled to ground;

the reference transistor pair comprises at a common drain a drain-gate node having a drain-gate voltage; and

a source of the clamp transistor is coupled to a high-gain node, a gate of the clamp transistor is coupled to a clamp voltage, and

a second stage coupled to the high-gain node and configured to generate an output voltage based on a difference between the input voltage and the reference voltage, the second stage comprising a resistor and an inverter transistor pair, wherein;

gates of the inverter transistor pair are coupled to the high-gain node of the first stage; and

the resistor couples the high-gain node of the first stage to a common drain of the inverter transistor pair and is configured to provide and/or draw current to and/or from the high-gain node of the first stage.

2. The circuit of claim 1, wherein the first stage further comprises an input transistor pair, wherein:

the input voltage is coupled to the input transistor pair;

the input transistor pair is coupled to the ground;

the input transistor pair comprises at a common drain the high-gain node having a high-gain node voltage; and

the drain-gate node is coupled to respective gates of p-type transistors in the input transistor pair and the reference transistor pair, respectively.

3. The circuit of claim 1, wherein the second stage is configured to draw current from the high-gain node when the high-gain node voltage rises.

4. The circuit of claim 1, wherein the second stage is configured to provide current to the high-gain node when the high-gain node voltage falls.

5. The circuit of claim 1, further comprising a third stage comprising an operational amplifier and a transistor and configured to:

provide the input voltage, wherein the input voltage is provided based on a high-impedance input voltage and a high-voltage power supply;

or

provide the reference voltage, wherein the reference voltage is provided based on a high-impedance reference voltage and a high-voltage power supply.

6. The circuit of claim 1, further comprising a third stage that comprises a high-impedance input transistor pair and a high-impedance reference transistor pair, wherein:

the high-impedance input transistor pair is configured to receive a high-impedance input voltage at gates of the high-impedance input transistor pair and provide to the first stage, from a common drain of the high-impedance input transistor pair, the input voltage; and

the high-impedance reference transistor pair is configured to receive a high-impedance reference voltage at gates of the high-impedance reference transistor pair and provide to the first stage, from a common drain of the high-impedance reference transistor pair, the reference voltage.

7. The circuit of claim 6, wherein the third stage further comprises:

a p-type transistor having a gate that is coupled to a p-type bias voltage, a source that is coupled to a power supply, and a drain that is coupled to a source of a p-type transistor in the high-impedance input transistor pair and a p-type transistor in the high-impedance reference transistor pair; and

an n-type transistor having a gate that is coupled to an n-type bias voltage, a source that is coupled to ground, and a drain that is coupled to a source of an n-type transistor in the high-impedance input transistor pair and an n-type transistor in the high-impedance reference transistor pair.

8. The circuit of claim 1, wherein the first stage comprises a folded cascode, the folded cascode comprising:

the input transistor pair;

the reference transistor pair coupled to the reference voltage, coupled to ground, and comprising a reference transistor pair node coupled to drains of the reference transistor pair; and

a low-impedance transistor pair coupled to a low-impedance voltage, coupled to ground, and comprising a low-impedance transistor pair node coupled to the drains of the low-impedance transistor pair, wherein;

the low-impedance transistor pair node is coupled to gates of p-type transistors in the low-impedance transistor pair, the input transistor pair, and the reference transistor pair.

9. The circuit of claim 8, wherein a drain of the clamp transistor coupled to the gates of p-type transistors in the input transistor pair and the reference transistor pair, respectively.

10. The circuit of claim 1, wherein the system is provided in a device selected from a group consisting of a set top box, a music player, a video player, an entertainment unit, a navigation device, a personal digital assistant (PDA), a fixed location data unit, a computer, a laptop, a tablet, a communications device, and a mobile phone.

11. A method, comprising:

receiving, at a first stage comprising a reference transistor pair, a clamp transistor, an input voltage and a reference voltage, wherein;

the reference voltage is coupled to the reference transistor pair;

the reference transistor pair is coupled to ground;

the reference transistor pair comprises at a common drain a drain-gate node having a drain-gate voltage; and

a source of the clamp transistor is coupled to a high-gain node, a gate of the clamp transistor is coupled to a clamp voltage; and

receiving, at a second stage comprising a resistor and an inverter transistor pair, ae high-gain node voltage, wherein;

gates of the inverter transistor pair are coupled to the high-gain node of the first stage; and

the resistor couples the high-gain node of the first stage to a common drain of the inverter transistor pair;

providing or drawing current to or from the high-gain node of the first stage; and

generating an output voltage based on a difference between the input voltage and the reference voltage.

12. The method of claim 11, wherein the first stage further comprises an input transistor pair, wherein:

the input voltage is coupled to the input transistor pair;

the input transistor pair is coupled to the ground; and

the input transistor pair comprises at a common drain the high-gain node having the high-gain node voltage; and

the drain-gate node is coupled to respective gates of p-type transistors in the input transistor pair and the reference transistor pair, respectively.

13. The method of claim 11, further comprising drawing current from the high-gain node when the high-gain node voltage rises.

14. The method of claim 11, further comprising providing current to the high-gain node when the high-gain node voltage falls.

15. The method of claim 11, further comprising:

providing, from a third stage comprising an operational amplifier and a transistor, the input voltage, wherein the input voltage is provided based on a high-impedance input voltage and a high-voltage power supply; and

/or

providing, from the third stage, the reference voltage, wherein the reference voltage is provided based on a high-impedance reference voltage and a high-voltage power supply.

16. The method of claim 11, further comprising:

receiving, at a third stage that comprises a high-impedance input transistor pair, a high-impedance input voltage at gates of the high-impedance input transistor pair;

providing to the first stage, from a common drain of the high-impedance input transistor pair, the input voltage;

receiving, at a high-impedance reference transistor pair in the third stage, a high-impedance reference voltage at gates of the high-impedance reference transistor pair; and

providing to the first stage, from a common drain of the high-impedance reference transistor pair, the reference voltage.

17. The method of claim 16, wherein the third stage further comprises:

a p-type transistor having a gate that is coupled to a p-type bias voltage, a source that is coupled to a power supply, and a drain that is coupled to a source of a p-type transistor in the high-impedance input transistor pair and a p-type transistor in the high-impedance reference transistor pair; and

an n-type transistor having a gate that is coupled to an n-type bias voltage, a source that is coupled to ground, and a drain that is coupled to a source of an n-type transistor in the high-impedance input transistor pair and an n-type transistor in the high-impedance reference transistor pair.

18. The method of claim 11, wherein the first stage comprises a folded cascode, the folded cascode comprising:

the input transistor pair;

a reference transistor pair coupled to the reference voltage, coupled to ground, and comprising a reference transistor pair node coupled to drains of the reference transistor pair; and

a low-impedance transistor pair coupled to a low-impedance voltage, coupled to ground, and comprising a low-impedance transistor pair node coupled to the drains of the low-impedance transistor pair, wherein;

the low-impedance transistor pair node is coupled to gates of p-type transistors in the low-impedance transistor pair, the input transistor pair, and the reference transistor pair.

19. The method of claim 18, wherein a drain of the clamp transistor is coupled to the gates of p-type transistors in the input transistor pair and the reference transistor pair, respectively.

20. The method of claim 11, wherein the method is implemented in a device selected from a group consisting of a set top box, a music player, a video player, an entertainment unit, a navigation device, a personal digital assistant (PDA), a fixed location data unit, a computer, a laptop, a tablet, a communications device, and a mobile phone.

21. A circuit, comprising:

means for receiving an input voltage and a reference voltage, wherein the means for receiving comprises means for providing a drain-gate voltage and means for clamping a high-gain node;

means for providing or drawing current to or from the high-gain node of a first stage; and

means for generating an output voltage based on a difference between the input voltage and the reference voltage.

22. The circuit of claim 21, wherein the means for receiving further comprises means for providing the high-gain node having a high-gain node voltage and means for receiving the high-gain node voltage.

23. The circuit of claim 21, wherein the means for providing or drawing current comprises means for drawing current from the high-gain node when the high-gain node voltage rises.

24. The circuit of claim 21, wherein the means for providing or drawing current comprises means for providing current to the high-gain node when the high-gain node voltage falls.

25. The circuit of claim 21, further comprising means for increasing impedance, the means for increasing impedance further comprising:

means for providing the input voltage, wherein the input voltage is provided based on a high-impedance input voltage and a high-voltage power supply;

or

means for providing the reference voltage, wherein the reference voltage is provided based on a high-impedance reference voltage and a high-voltage power supply.

26. The circuit of claim 21, further comprising means for increasing impedance, the means for increasing impedance further comprising:

means for receiving a high-impedance input voltage and a high-impedance reference voltage; and

means for providing the input voltage and the reference voltage to the means for receiving.

27. The circuit of claim 26, wherein the means for increasing impedance further comprises:

means for providing current to the means for increasing impedance, wherein the means for providing current is coupled to a power supply; and

means for sinking current from the means for increasing impedance, wherein the means for sinking current is coupled to ground.

28. The circuit of claim 21, wherein the means for receiving comprises a folded cascode, the folded cascode comprising:

an input transistor pair;

a reference transistor pair coupled to the reference voltage, coupled to ground, and comprising a reference transistor pair node coupled to drains of the reference transistor pair; and

a low-impedance transistor pair coupled to a low-impedance voltage, coupled to ground, and comprising a low-impedance transistor pair node coupled to the drains of the low-impedance transistor pair, wherein;

the low-impedance transistor pair node is coupled to gates of p-type transistors in the low-impedance transistor pair, the input transistor pair, and the reference transistor pair.

29. The circuit of claim 21, wherein the means for clamping the high-gain node is coupled to the means for providing the high-gain node and the means for providing the drain-gate voltage.

30. The circuit of claim 21, wherein the system is provided in a device selected from a group consisting of a set top box, a music player, a video player, an entertainment unit, a navigation device, a personal digital assistant (PDA), a fixed location data unit, a computer, a laptop, a tablet, a communications device, and a mobile phone.