Switched current control module and method therefor

• US 10,116,287 B2
• Filed: 01/18/2017
• Issued: 10/30/2018
• Est. Priority Date: 06/20/2016
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Inventors: Bosvieux, Tristan, Guillermand, Jeremy, Pigott, John
• Primary Examiner(s): Torres-Rivera, Alex
• Application Number:
  US15/409,024
• Publication Number:
  US 20170366171A1
• Time in Patent Office: 650 Days
• Field of Search: 323282
• CPC Class Codes: H02M 1/0003 Details of control, feedback or regulation circuits
• CPC Class Codes: H02M 1/0025 Arrangements for modifying reference values, feedback values or error values in the control loop of a converter
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H03K 3/011 Modifications of generator to compensate for variations in physical values, e.g. voltage, temperature to maintain energy constant H03K3/015
• CPC Class Codes: H03K 3/012 Modifications of generator to improve response time or to decrease power consumption
• CPC Class Codes: H03K 3/013 Modifications of generator to prevent operation by noise or interference

Abstract

A switched current control module comprises a hysteretic control component arranged to receive high and low threshold values and an indication of a current flow through a load, and to output a switched current control signal based on a comparison of the current flow indication to the high and low threshold values. A threshold generator is arranged to generate the high and low threshold values based on a base threshold value and a hysteretic excursion value. A base threshold value generator is arranged to generate the base threshold value based on the current flow indication and a setpoint value. A hysteretic excursion value generator is arranged to receive an indication of a switching frequency of the switched current control signal output by the hysteretic control component, and to generate the hysteretic excursion value based on the indicated switching frequency of the switched current control signal.

Claims

1. A switched current control module comprising:

a hysteretic control component arranged to receive a high threshold value signal, a low threshold value signal and an indication of a current flow through a load, and to output a switched current control signal based on a comparison of the current flow indication to the high and low threshold value signals;

a threshold generator component arranged to generate the high and low threshold value signals based on a base threshold value and a hysteretic excursion value;

a base threshold value generator component arranged to receive the current flow indication and a setpoint value, to determine an average current error value for the current flow through the load based on the received indication of current flow through the load and the setpoint value, and to generate the base threshold value signal based on the determined average current error value; and

a hysteretic excursion value generator component arranged to receive an indication of a switching frequency of the switched current control signal output by the hysteretic control component, and to generate the hysteretic excursion value signal based on the indicated switching frequency of the switched current control signal.

2. The switched current control module of claim 1, wherein the base threshold value generator component is arranged to generate the base threshold value signal proportional to the determined average current error value.

3. The switched current control module of claim 1, wherein the hysteretic excursion value generator component is arranged to derive a switching frequency value based on the indicated switching frequency of the switched current control signal, and to generate the hysteretic excursion value signal based on the derived switching frequency value and a reference value.

4. The switched current control module of claim 3, wherein the hysteretic excursion value generator component is arranged to derive the switching frequency value inversely proportional to the indicated switching frequency of the switched current control signal and to subtract the switching frequency value from the reference value to generate the hysteretic excursion value signal.

5. The switched current control module of claim 1, wherein the threshold generator component comprises:

an addition component arranged to receive the base threshold value signal and the hysteretic excursion value signal, and to generate the high threshold value signal by summing the base threshold value signal and the hysteretic excursion value signal; and

a subtraction component arranged to receive the base threshold value signal and the hysteretic excursion value signal, and to generate the low threshold value signal by subtracting the hysteretic excursion value signal from the base threshold value signal.

6. A semiconductor die comprising the switched current control module according to claim 1.

7. A method of generating a switched current control signal;

the method comprising;

receiving an indication of a current flow through a load;

determining an average current error for the current flow through the load based on the received indication of current flow through the load and a setpoint value;

generating a base threshold value based on the determined average current error value;

receiving an indication of a switching frequency of the switched current control signal;

generating a hysteretic excursion value based on the indicated switching frequency of the switched current control signal;

generating a high threshold value and a low threshold value based on the base threshold value and the hysteretic excursion value; and

applying a hysteresis function to the indicated current flow using the high and low threshold values to generate the switched current control signal.

8. The method of claim 7, wherein the method comprises generating the base threshold value signal proportional to the determined average current error value.

9. The method of claim 7, wherein the method comprises deriving a switching frequency value based on the indicated switching frequency of the switched current control signal, and generating the hysteretic excursion value signal based on the derived switching frequency value and a reference value.

10. The method of claim 9, wherein the method comprises deriving the switching frequency value inversely proportional to the indicated switching frequency of the switched current control signal and subtracting the switching frequency value from the reference value to generate the hysteretic excursion value signal.

11. The method of claim 7, wherein the method comprises:

generating the high threshold value by summing the base threshold value and the hysteretic excursion value; and

generating the low threshold value by subtracting the hysteretic excursion value from the base threshold value.