Voltage sampler driver with enhanced high-frequency gain

• US 10,003,315 B2
• Filed: 01/25/2017
• Issued: 06/19/2018
• Est. Priority Date: 01/25/2016
• Status: Active Grant

• Current Assignee: Kandou Labs, SA
• Original Assignee: Kandou Labs, SA
• Inventors: Tajalli, Armin
• Primary Examiner(s): Mottola, Steven J
• Application Number:
  US15/415,831
• Publication Number:
  US 20170214374A1
• Time in Patent Office: 510 Days
• Field of Search: 330252-261
• CPC Class Codes: H03F 2200/366 Multiple MOSFETs are coupled in parallel
• CPC Class Codes: H03F 2203/45022 One or more added resistors to the amplifying transistors in the differential amplifier
• CPC Class Codes: H03F 3/45179 using MOSFET transistors as the active amplifying circuit H03F3/45278 takes precedence
• CPC Class Codes: H03F 3/45183 Long tailed pairs H03F3/4521, H03F3/45237 take precedence
• CPC Class Codes: H03F 3/45197 Pl types H03F3/45224, H03F3/45251 take precedence
• CPC Class Codes: H03F 3/45632 in differential amplifiers with FET transistors as the active amplifying circuit H03F3/4578 takes precedence
• CPC Class Codes: H03G 3/3036 in high-frequency amplifiers or in frequency-changers H03G3/3052, H03G3/32, H03G3/34 take precedence
• CPC Class Codes: H03G 3/3089 Control of digital or coded signals
• CPC Class Codes: H04L 25/0272 Arrangements for coupling to multiple lines, e.g. for differential transmission
• CPC Class Codes: H04L 25/03133 with a non-recursive structure H04L25/03127 takes precedence
• CPC Class Codes: H04L 25/06 Dc level restoring means; Bias distortion correction ; Decision circuits providing symbol by symbol detection

Abstract

Methods and systems are described for receiving, at an input differential branch pair, a set of input signals, and responsively generating a first differential current, receiving, at an input of an offset voltage branch pair, an offset voltage control signal, and responsively generating a second differential current, supplementing a high-frequency component of the second differential current by injecting a high-pass filtered version of the set of input signals into the input of the offset voltage branch pair using a high-pass filter, and generating an output differential current based on the first and second differential currents using an amplifier stage connected to the input differential branch pair and the offset voltage branch pair.

Claims

1. An apparatus comprising:

a voltage sampler driver configured to generate an output differential current from at least a first and a second differential current, the voltage sampler driver comprising;

an input differential branch pair configured to receive a set of input signals, each branch of the differential branch pair comprising one or more transistors configured to generate the first differential current;

an offset voltage branch pair configured to receive, at an input, an offset voltage control signal, each branch of the offset differential branch pair comprising one or more transistors configured to generate the second differential current;

an amplifier stage connected to the voltage sampler driver, the amplifier stage configured to generate a differential output voltage based on the output differential current; and

a high-pass filter configured to supplement a high-frequency component of the second differential current by injecting a high-pass filtered version of the set of input signals into the input of the offset voltage branch pair.

2. The apparatus of claim 1, wherein the voltage sampler driver further comprises respective tail current sources, the respective tail current sources configured to enable the input differential branch pair and offset differential branch pair.

3. The apparatus of claim 2, wherein the respective tail current sources are periodically enabled according to an input clock signal.

4. The apparatus of claim 1, wherein the amplifier stage comprises a pair of load resistors configured to generate the differential output voltage based on the output differential current.

5. The apparatus of claim 4, wherein the amplifier stage further comprises a pair of capacitors, each capacitor connected between one terminal of a corresponding load resistor and ground.

6. The apparatus of claim 5, wherein the pair of load resistors are tunable.

7. The apparatus of claim 6, wherein the amplifier stage further comprises an adjustable tail current source.

8. The apparatus of claim 7, wherein a product of a current magnitude of the adjustable tail current source and an impedance magnitude of one of the load resistors is constant, and wherein the pair of load resistors and the tunable current source have a bandwidth control input to adjust bandwidth.

9. The apparatus of claim 7, wherein a product of a current magnitude of the adjustable tail current source and an impedance magnitude of one of the load resistors is not constant, the pair of load resistors and the adjustable tail current source having a power control input to adjust power consumption.

10. The apparatus of claim 6, wherein each tunable load resistor comprises a plurality of resistors in a parallel network, each resistor of the plurality having a corresponding switch connected between the resistor and a common node of the parallel network, and wherein each switch is configured to connect or disconnect the resistor from the parallel network based on a respective control signal.

11. A method comprising:

receiving, at an input differential branch pair, a set of input signals, and responsively generating a first differential current;

receiving, at an input of an offset voltage branch pair, an offset voltage control signal, and responsively generating a second differential current;

supplementing a high-frequency component of the second differential current by injecting a high-pass filtered version of the set of input signals into the input of the offset voltage branch pair using a high-pass filter; and

generating an output differential current based on the first and second differential currents using an amplifier stage connected to the input differential branch pair and the offset voltage branch pair.

12. The method of claim 11, wherein generating the first and second differential currents comprises enabling corresponding tail current sources for the input differential branch pair and the offset differential branch pair.

13. The method of claim 12, further comprising periodically enabling the respective tail current sources using an input clock signal.

14. The method of claim 11, further comprising generating a differential output voltage by drawing the output differential current through a pair of load resistors.

15. The method of claim 14, wherein each load resistor has a corresponding capacitor connected between one terminal of the load resistor and ground.

16. The method of claim 15, wherein the pair of load resistors are tunable.

17. The method of claim 16, wherein the amplifier stage further comprises an adjustable tail current source.

18. The method of claim 17, wherein a product of a current magnitude of the adjustable tail current source and an impedance magnitude of one of the load resistors is constant, and wherein the method further comprises adjusting the pair of load resistors and the adjustable tail current source to adjust bandwidth.

19. The method of claim 17, wherein a product of a current magnitude of the adjustable tail current source and an impedance magnitude of one of the load resistors is not constant, and wherein the method further comprises adjusting the pair of load resistors and the adjustable tail current source to adjust power consumption.

20. The method of claim 16, wherein each tunable load resistor comprises a plurality of resistors in a parallel network, and wherein the method further comprises selectably enabling each resistor of the plurality of resistors according to a corresponding switch receiving a corresponding control signal.