Harvesting ringing energy using a bootstrap circuit

Patent metadata

Field	Value
Publication number	US-11711007-B2
Application number	US-202117315444-A
Country	US
Kind code	B2
Filing date	May 10, 2021
Priority date	May 10, 2021
Publication date	Jul 25, 2023
Grant date	Jul 25, 2023

Abstract

An apparatus is disclosed for harvesting ringing energy. In an example aspect, the apparatus includes a bootstrap circuit. The bootstrap circuit includes a bootstrap capacitor and a bootstrap switch. The bootstrap switch includes a first terminal configured to accept an input voltage. The bootstrap switch also includes a second terminal coupled to the bootstrap capacitor. The bootstrap switch additionally includes a body diode comprising an anode coupled to the first terminal and a cathode coupled to the second terminal. The bootstrap switch is configured to be in an open state to charge the bootstrap capacitor via the body diode. The bootstrap switch is also configured to provide a voltage at the second terminal of the bootstrap switch. The voltage is greater than an average of the input voltage.

First claim

What is claimed is:

1. An apparatus comprising:
a bootstrap circuit comprising:
a bootstrap capacitor; and
a bootstrap switch comprising:
a first terminal configured to accept an input voltage, the input voltage having voltage ringing that causes peaks of the input voltage to be greater than an average of the input voltage;
a second terminal coupled to the bootstrap capacitor; and
a body diode comprising an anode coupled to the first terminal and a cathode coupled to the second terminal,

the bootstrap switch configured to:
be in an open state to charge the bootstrap capacitor via the body diode; and
provide a voltage at the second terminal of the bootstrap switch, the voltage greater than the average of the input voltage.

2. The apparatus of claim 1 , wherein the bootstrap switch is configured to charge the bootstrap capacitor via the body diode based on the voltage ringing being present in the input voltage.

3. The apparatus of claim 1 , wherein an average of the voltage at the second terminal is approximately two times larger than the average of the input voltage.

4. The apparatus of claim 1 , wherein the bootstrap switch is further configured to selectively:
be in a closed state to charge the bootstrap capacitor via an induced channel; or
be in the open state to charge the bootstrap capacitor via the body diode.

5. The apparatus of claim 4 , wherein the bootstrap switch is configured to selectively:
cause the voltage at the second terminal to be at a first level responsive to being in the closed state to charge the bootstrap capacitor via the induced channel; or
cause the voltage at the second terminal to be at a second level responsive to being in the open state to charge the bootstrap capacitor via the body diode, the second level greater than the first level.

6. The apparatus of claim 5 , wherein:
the first level is approximately equal to the average of the input voltage; and
the second level is approximately equal to twice the average of the input voltage.

7. The apparatus of claim 4 , wherein the bootstrap circuit comprises a bootstrap driver circuit configured to:
monitor the input voltage; and
responsive to the input voltage being greater than a voltage threshold, cause the bootstrap switch to be in the closed state to charge the bootstrap capacitor via the induced channel; or
responsive to the input voltage being less than the voltage threshold, cause the bootstrap switch to be in the open state to charge the bootstrap capacitor via the body diode.

8. The apparatus of claim 1 , wherein:
the bootstrap switch comprises a p-channel metal-oxide-semiconductor field-effect transistor comprising:
a drain terminal as the first terminal;
a source terminal as the second terminal; and
a gate terminal; and

the bootstrap switch is configured to operate in the open state responsive to the p-channel metal-oxide-semiconductor field-effect transistor being biased according to a cut-off region.

9. The apparatus of claim 8 , wherein the bootstrap circuit comprises a bootstrap driver circuit configured to:
provide a gate voltage at the gate terminal of the p-channel metal-oxide-semiconductor field-effect transistor; and
cause the gate voltage to be greater than or equal to a voltage at the source terminal of the p-channel metal-oxide-semiconductor field-effect transistor to bias the p-channel metal-oxide-semiconductor field-effect transistor according to the cut-off region.

10. The apparatus of claim 9 , wherein the bootstrap driver circuit is configured to connect the gate terminal of the p-channel metal-oxide-semiconductor field-effect transistor to the source terminal of the p-channel metal-oxide-semiconductor field-effect transistor to cause the gate voltage to be approximately equal to the voltage at the source terminal.

11. The apparatus of claim 1 , wherein:
the bootstrap capacitor comprises:
a first terminal coupled to the second terminal of the bootstrap switch; and
a second terminal; and

the apparatus comprises a switch-mode power supply, the switch-mode power supply comprising:
the bootstrap circuit; and
a switching circuit comprising:
a switch coupled between the first terminal of the bootstrap switch and the second terminal of the bootstrap capacitor; and
a driver coupled to the switch, the driver comprising:
a positive supply terminal coupled to the second terminal of the bootstrap switch and the first terminal of the bootstrap capacitor; and
a negative supply terminal coupled to the second terminal of the bootstrap capacitor.

12. The apparatus of claim 11 , wherein the switch comprises an n-channel metal-oxide-semiconductor field-effect transistor.

13. The apparatus of claim 11 , wherein the bootstrap switch is configured to selectively:
be in an opposite state as the switch responsive to the input voltage being greater than a voltage threshold; or
be in the open state responsive to the input voltage being less than the voltage threshold.

14. The apparatus of claim 11 , wherein the switch-mode power supply is configured to:
be coupled between a power source and a load; and
transfer power from the power source to the load.

15. The apparatus of claim 14 , wherein the switch-mode power supply comprises an inductor coupled between the load and the second terminal of the bootstrap capacitor.

16. The apparatus of claim 11 , wherein the switch-mode power supply comprises a buck converter or a buck-boost converter.

17. An apparatus comprising:
a bootstrap circuit comprising:
capacitance means for storing energy; and
switching means for charging the capacitance means, the switching means comprising:
a first terminal configured to accept an input voltage, the input voltage having voltage ringing that causes peaks of the input voltage to be greater than an average of the input voltage;
a second terminal coupled to the capacitance means; and
rectification means for charging the capacitance means based on the switching means being in an open state and providing a voltage at the second terminal that is greater than the average of the input voltage, the rectification means comprising a body diode of the switching means.

18. The apparatus of claim 17 , wherein the switching means is configured to selectively:
be in a closed state to charge the capacitance means via an induced channel and cause the voltage at the second terminal to be at a first level; or
be in the open state to charge the capacitance means via the rectification means and cause the voltage at the second terminal to be at a second level that is greater than the first level.

19. The apparatus of claim 18 , wherein:
the first level is approximately equal to the average of the input voltage; and
the second level is approximately equal to twice the average of the input voltage.

20. The apparatus of claim 17 , wherein:
the capacitance means comprises a first terminal and a second terminal, the first terminal coupled to the second terminal of the switching means; and
the apparatus comprises a switch-mode power supply, the switch-mode power supply comprising:
the bootstrap circuit; and
a switching circuit comprising:
a switch coupled between the first terminal of the switching means and the second terminal of the capacitance means; and
a driver coupled to the switch, the driver comprising:
a positive supply terminal coupled to the second terminal of the switching means and the first terminal of the capacitance means; and
a negative supply terminal coupled to the se

Assignees

• Qualcomm Inc

Inventors

• Stockstad Troy Lynn
• Wan Yi-Cheng
• Koski Marko
• KOSARAJU Ajay Kumar

Classifications

• H02M1/0006 Primary

  Arrangements for supplying an adequate voltage to the control circuit of converters · CPC title

• H02M1/08 Primary

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title

• H02M3/156

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

• H02M3/1582

  Buck-boost converters (H02M3/1584 takes precedence) · CPC title

• H02J50/001 Primary

  Energy harvesting or scavenging · CPC title