Adaptive non-positive inductor current detector (ANPICD)

• US 8,710,877 B2
• Filed: 07/31/2012
• Issued: 04/29/2014
• Est. Priority Date: 10/05/2009
• Status: Active Grant

• Current Assignee: Adaptive Digital Power Incorporated
• Original Assignee: Adaptive Digital Power Incorporated
• Inventors: Wile, Donald, Wu, Andrew
• Primary Examiner(s): JAGER, RYAN C
• Application Number:
  US13/562,317
• Publication Number:
  US 20130169323A1
• Time in Patent Office: 637 Days
• Field of Search: 327/110, 323/285, 323/223
• US Class Current: 327/110
• CPC Class Codes: G01R 19/0092 measuring current only all subgroups of G01R19/00 take precedence
• CPC Class Codes: G01R 19/25 using digital measurement techniques
• CPC Class Codes: G01R 31/40 Testing power supplies testing photovoltaic devices H02S50/10
• CPC Class Codes: G05F 1/40 using discharge tubes or semiconductor devices as final control devices
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 3/1588 comprising at least one synchronous rectifier element H02M3/1582, H02M3/1584 take precedence
• CPC Class Codes: H03K 17/133 in field-effect transistor switches
• CPC Class Codes: H03K 2217/0036 Means reducing energy consumption
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

Systems and methods are disclosed to detect current for an output load with an inductor. The system includes a high side power transistor a low side power transistor coupled to the high side power transistor; and a controller coupled to the high and low side power transistors.

Claims

1. An adaptive current detector for an output inductor from a switched voltage output of a switching regulator, comprising

a. a high side power transistor;

b. a low side power transistor;

c. an inductor coupled to the high and low side power transistors; and

d. a detector asserting a first signal indicating when the high and low side power transistors are off and an inductor current is non-positive and used in an adaptive loop to adjust when the low side transistor is turned off.

2. The adaptive current detector of claim 1, wherein the detector adapts an on-time of the low side power transistor in response to a current in the inductor.

3. The adaptive current detector of claim 2, wherein a low side power transistor on-time is adjusted by the adaptive loop to improve switching regulator efficiency.

4. The adaptive current detector of claim 2 wherein the detector provides a means to accurately detect when the inductor current reaches zero during the switching cycle.

5. The adaptive current detector of claim 1, wherein the detector generates a second signal with a logic gate coupled to the first signal and a pulse generator supplying a pulse width for the predetermined period.

6. The adaptive current detector of claim 1, comprising an integrator coupled to a second signal and to the low side power transistor to control when the low side power transistor turns off, wherein the integrator reduces or increases an output voltage or digital count when each second signal is asserted.

7. The adaptive current detector of claim 6, wherein the integrator comprises an operational amplifier.

8. The adaptive current detector of claim 6, wherein the integrator comprises an up/down counter.

9. The adaptive current detector of claim 1, comprising a timer coupled to the low side power transistor to incrementally adjust when the low side power transistor is turned on or off.

10. The adaptive current detector of claim 9, wherein the timer comprises a ramp generator.

11. The adaptive current detector of claim 9, wherein the timer comprises a counter.

12. The adaptive current detector of claim 1, comprising a comparator to turn off the low side power transistor.

13. The adaptive current detector of claim 12, wherein the comparator comprises a counter coupled to a timer having a timer count output and wherein the comparator turns off the low side power transistor when the timer counter output exceeds the count output.

14. The adaptive current detector of claim 12, comprising logic coupled to the comparator output, controlling the turn on and turn off of the low side power transistor.

15. A current detector for an output inductor, comprising

a. a high side power field effect transistor (FET);

b. a low side FET coupled to the high side FET;

c. means for asserting a first signal indicating when the high and low side power transistors are off and an inductor current is non-positive; and

d. an adaptive loop to adjust when the low side transistor is turned off.

16. The detector of claim 15, comprising:

a. means for integrating the output of said means for asserting a second signal;

b. timer means for incrementally adjusting when the low side power transistor is turned on or off; and

c. means for comparing the integrating means with the timing means and turning off the low side power in response to the comparing means.

17. An adaptive current detector for an output inductor from a switched voltage output of a switching regulator, comprising

a. a high side power transistor;

b. a low side power transistor;

c. an inductor coupled to the high and low side power transistors;

d. a detector asserting a first signal indicating when the high and low side power transistors are off and an inductor current is non-positive; and

e. a controller coupled to the detector and the high and low side power transistors to turn off the low side power transistor when the first signal is asserted within a predetermined period when the low side power transistor turns off.

18. The detector of claim 17, wherein the controller asserts a second signal when the first signal is asserted within a predetermined period when the low side power transistor turns off.

19. The detector of claim 17, wherein the controller adaptively turns off the low side power transistor in response to a time position of the first and second signals.

20. The detector of claim 17, further comprising:

a. a detector to determine when the controller is active within a predetermined period when the low side power transistor turns off;

b. an integrator coupled to the detector; and

c. a comparator coupled to the timer and the integrator, wherein the comparator output turns off the low side power transistor.