Voltage regulator with load compensation

Patent metadata

Field	Value
Publication number	US-9444478-B2
Application number	US-201514848837-A
Country	US
Kind code	B2
Filing date	Sep 9, 2015
Priority date	Sep 10, 2014
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

A voltage regulation system provides a relatively stable voltage source without introducing the typical costs of a ground buffer. The disclosed voltage regulation system includes a voltage regulator that is operative to detect a change of the load current and regulate a current bypass mechanism to stabilize a total supply current. For example, the voltage regulator includes a current sensor and a current compensation circuit. The current sensor is configure to generate a current compensation signal based on the load current change, whereas the current compensation circuit is configured to adjust a bypass current in response to the current compensation signal. As a result, the bypass current dynamically compensates the load current change such that the ground voltage of a variable load becomes relatively stable over a range of load currents.

First claim

What is claimed is:

1. A reference voltage regulation (RVR) circuit for supplying a reference voltage across a variable load, the RVR circuit comprising:
a first output node configured to deliver an output current to the variable load;
a second output node configured to collect the output current from the variable load;
a current compensation circuit coupled between the first and second output nodes, the current compensation circuit having a control terminal configured to receive a current compensation signal for adjusting a compensation current across the first and second output nodes via the current compensation circuit; and
a current sensor coupled with the first and second output nodes to sense a change of the output current, the current sensor configured to generate the current compensation signal based on the sensed change of the output current.

2. The RVR circuit of claim 1 , wherein the current sensor includes:
a supply current path having a supply output node coupled with the first output node to deliver a supply current sustaining the output current and the compensation current; and
a monitoring current path configured to deliver a monitoring current responsive to the sensed change of the output current, the monitoring current path having a monitoring output node to deliver the current compensation signal based on the monitoring current.

3. The RVR circuit of claim 2 , wherein:
the supply current path includes a first p-channel transistor configured to conduct the supply current based on a gate-source bias voltage responsive to the sensed change of the output current; and
the monitoring current path includes a second p-channel transistor configured to conduct the monitoring current proportional to the supply current and based on the gate-source bias voltage responsive to the sensed change of the output current.

4. The RVR circuit of claim 3 , wherein the monitoring current path includes:
a resistor coupled with the second p-channel transistor to establish a monitoring set voltage based on the monitoring current; and
a comparison circuit configured to generate the current compensation signal based on a comparison between the monitoring set voltage and a predetermined set voltage, the comparison circuit having:
a first input coupled with the resistor to receive the monitoring set voltage;
a second input configured to receive the predetermined set voltage; and
a comparison output coupled with the monitoring output node to deliver the current compensation signal.

5. The RVR circuit of claim 4 , wherein the predetermined set voltage is predetermined based on a function of the resistor and an estimated maximum value of the output current.

6. The RVR circuit of claim 4 , wherein the current compensation circuit includes an n-channel transistor having:
a drain node coupled with the first output node;
a gate node coupled with the monitoring output node via the control terminal to receive the current compensation signal; and
a source node coupled with the second output node.

7. The RVR circuit of claim 3 , wherein the monitoring current path includes:
a current source coupled with the second p-channel transistor via the monitoring output node, the current source configured to conduct a set current adjusting the current compensation signal at the monitoring output node.

8. The RVR circuit of claim 7 , wherein the set current is predetermined based on a function of an estimated maximum value of the output current.

9. The RVR circuit of claim 7 , wherein the current compensation circuit includes a p-channel transistor having:
a source node coupled with the first output node;
a gate node coupled with the monitoring output node via the control terminal to receive the current compensation signal; and
a drain node coupled with the second output node.

10. The RVR circuit of claim 1 , wherein the current sensor includes an amplifier coupled with the first output node, the amplifier configured to generate a feedback control signal proportional to the change of the output current.

11. The RVR circuit of claim 1 , wherein the current sensor includes:
a first sensing stage coupled with the first output node to sense the change of the output current, the first sensing stage configured to generate a current sense signal responding positively to the sensed change of the output current; and
a second sensing stage coupled with the first sensing stage to receive the current sense signal, the second sensing stage configured to generate the current compensation signal based on a comparison between the current sense signal and a predetermined set voltage.

12. The RVR circuit of claim 11 , wherein the first sensing stage includes:
a comparison circuit having a negative input lead coupled with the first output node, a positive input lead configured to receive a reference input signal, and an output lead configured to deliver the current sense signal; and
a resistor coupled in series between the output lead and the first output node.

13. The RVR circuit of claim 11 , wherein the second sensing stage includes:
a comparison circuit having a negative input lead coupled with the first sensing stage to receive the current sense signal, a positive input lead configured to receive a predetermined set voltage, and an output lead configured to deliver the current compensation signal.

14. The RVR circuit of claim 1 , wherein the current sensor includes:
a first comparison circuit having a first negative input lead coupled with the first output node, a first positive input lead configured to receive a reference input signal, and a first output lead;
a second comparison circuit having a second negative input lead coupled with the first output lead of the first comparison circuit, a second positive input lead configured to receive a predetermined set voltage, and a second output lead coupled with the control terminal of the current compensation circuit; and
a resistor coupled in series between the first output lead and the first output node.

15. The RVR circuit of claim 1 , wherein the current sensor is configured to adjust the current compensation signal to increase the compensation current upon sensing a reduction of the output current.

16. The RVR circuit of claim 1 , wherein the current sensor is configured to adjust the current compensation signal to reduce the compensation current upon sensing an increment of the output current.

17. The RVR circuit of claim 1 , wherein the current sensor is configured to adjust the current compensation signal to stabilize a supply current including the output current and the compensation current.

18. A reference voltage regulation (RVR) circuit for supplying a reference voltage across a variable load, the RVR circuit comprising:
a first output node configured to deliver an output current to the variable load;
a second output node configured to collect the output current from the variable load;
a current compensation circuit coupled between the first and second output nodes, the current compensation circuit having a control terminal configured to receive a current compensation signal for adjusting a compensation current across the first and second output nodes via the current compensation circuit; and
a current sensor including:
a supply current path having a supply output node coupled with the first output node to deliver a supply current sustaining the output current and the compensation current; and
a monitoring current path configured to deliver a monitoring current responsive to a sensed change of the o

Assignees

• Texas Instruments Inc

Inventors

• Shill Mark Allan
• Wang Binan

Classifications

• H03M1/66

  Digital/analogue converters ({H03M1/001 – } H03M1/10 take precedence) · CPC title

• G05F3/262 Primary

  using field-effect transistors only · CPC title

• G05F3/30

  Regulators using the difference between the base-emitter voltages of two bipolar transistors operating at different current densities (G05F3/26 takes precedence) · CPC title

• H03M1/06 Primary

  Continuously compensating for, or preventing, undesired influence of physical parameters (periodically, {e.g. by using stored correction values,} H03M1/10) · CPC title

• H02M3/156

  with automatic control of output voltage or current, e.g. switching regulators · CPC title