Single inductor multiple output boost regulator

• US 6,075,295 A
• Filed: 04/14/1997
• Issued: 06/13/2000
• Est. Priority Date: 04/14/1997
• Status: Expired due to Term

• Current Assignee: Fairchild Semiconductor Corporation (ON Semiconductor Corporation)
• Original Assignee: Micro Linear Corporation (Qorvo, Inc.)
• Inventors: Li, Thomas
• Primary Examiner(s): FLEMING, FRITZ M
• Assistant Examiner(s): FLEMING, FRITZ M
• Application Number:
  US08/840,279
• Time in Patent Office: 1,156 Days
• Field of Search: 307/38, 307/39, 307/41, 323/222
• US Class Current: 307/39
• CPC Class Codes: H02M 1/009 having two or more independently controlled outputs for DC-DC converter with intermediate AC H02M3/33561
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load

Abstract

The present invention provides two or more output voltages from one input voltage and one inductor. Each output voltage is formed by a switch controlling the charge delivered to each of the corresponding output capacitors. Preferably, a diode is placed in series with each switch that controls the charging of the output capacitors to prevent any extraneous stray current from escaping while the switch is closed. The controller utilizes pulse width modulation to deliver the correct amount of energy to each load and to synchronize the order of energy delivery to each load. The use of one input voltage and one inductor for charging multiple output voltages simplifies the complexity of the circuit of the present invention and eliminates the need for a single inductor dedicated to each load. Further, the predetermined output voltage level for each load can be changed without modifying the passive elements in the circuit. Rather, the predetermined voltage level for each load is changed by re-programming the controller thereby modifying the duration and frequency of the pulse received by the respective load from the charging inductor.

Claims

1. A circuit for providing multiple output boost regulation for a plurality of loads comprising:

a. a charging means comprising a power source and a passive element to store a charge from the power source;

b. a switching circuit comprising a plurality of switches for connection to each of the plurality of loads and the charging means; and

c. a controller for coordinating the switching circuit to regulate and sequentially direct the charge from the passive element to each of the plurality of loads so that a regulated DC output voltage level is obtained at each of the plurality of loads.

2. The circuit according to claim 1, wherein the passive element in the charging means is an inductor.

3. The circuit according to claim 1, further comprising a storage means configured in parallel with each of the plurality of loads wherein the storage means is a capacitor.

4. The circuit according to claim 1, wherein the controller includes a means for sensing the output voltage level at each of the plurality of loads.

5. The circuit according to claim 1 further comprising a plurality of diodes wherein each of the plurality of diodes is coupled between the charging means and a corresponding one of the plurality of loads.

6. The circuit according to claim 1 wherein the pulse width modulation circuit is configured to charge each of the plurality of loads within a same charge cycle of the charging means in response to the predetermined output voltage level.

7. The circuit according to claim 1, wherein the controller further comprises a pulse width modulation circuit.

8. A circuit for providing multiple output boost regulation for a plurality of loads comprising:

a. a charging means comprising a power source and a passive element;

b. a plurality of load switches wherein each one of the plurality of load switches is coupled between one of the plurality of loads and the charging means;

c. a charging switch coupled to control the charging means; and

d. a programmable controller for coordinating the plurality of switches and the charging switch to sequentially direct a current to each of the plurality of loads wherein each of the plurality of loads receives a corresponding regulated DC voltage.

9. The circuit according to claim 8 further comprising a plurality of diodes wherein a one of the plurality of diodes is coupled in series with each of the plurality of load switches to prevent any extraneous current from escaping from one of the plurality of loads while a corresponding one of the plurality of load switches is closed.

10. The circuit according to claim 8 wherein during a first charging cycle the charging means charges the passive element with a first amount of energy and wherein during a first discharging cycle the controller directs a portion of the first amount of energy to a first one of the plurality of loads and does not direct energy to any other load, and wherein during a second charging cycle the charging means charges the passive element with a second amount of energy and wherein during a second discharging cycle the controller directs a portion of the second amount of energy to a second one of the plurality of loads and does not direct energy to any other load.

11. The circuit according to claim 10 wherein the first amount of energy is based upon a level of voltage across the first one of the plurality of loads prior to the first charging cycle and wherein the second amount of energy is based upon a level of voltage across the second one of the plurality loads prior to the second charging cycle.

12. The circuit according to claim 10 wherein the portion of the first amount of energy is based upon a level of voltage across the first one of the plurality of loads during the first discharge cycle and wherein portion of the second amount of energy is based upon a level of voltage across the second one of the plurality of loads during the second discharge cycle.

13. The circuit according to claim 8 wherein during a charging cycle the charging means charges the passive element with an amount of energy and wherein during a discharging cycle the controller directs a first portion of the amount of energy to a first one of the plurality of loads and a second portion of the amount of energy to a second one of the plurality of loads.

14. The circuit according to claim 13 wherein the amount of energy is based upon a level of voltage across the first one of the plurality of loads prior to the charging cycle and upon a level of voltage across the second one of plurality of loads prior to the charging cycle.

15. The circuit according to claim 13 wherein the first portion of the amount of energy is based upon a level of voltage across the first one of the plurality of loads prior to the charging cycle and wherein the second portion of the amount of energy is based upon a level of voltage across the second one of the plurality of loads prior to the charging cycle.

16. The circuit according to claim 13 wherein the first portion of the amount of energy is based upon a level of voltage across the first one of the plurality of loads during the discharging cycle and wherein the second portion of the amount of energy is based upon a level of voltage across the second one of the plurality of loads during the discharging cycle.

17. The circuit according to claim 13 wherein the controller selectively directs one of the following to occur first in response to voltage levels across the first one and the second one of the plurality of loads:

the first portion of the amount of energy directed to the first one of the plurality of loads and the second portion of the amount of energy directed to the second one of the plurality of loads.

18. The circuit according to claim 13 wherein the controller selectively directs one of the following to occur first in response to voltage levels across the first one and the second one of the plurality of loads:

the first portion of the amount of energy directed to the first one of the plurality of loads and the second portion of the amount of energy directed to the second one of the plurality of loads.

19. A method of charging a plurality of loads comprising the steps of:

a. storing a charge;

b. receiving an output voltage level from each of the plurality of loads; and

c. sequentially distributing the charge during a discharge cycle to each of the plurality of loads via a current pulse according to the output voltage level from each of the plurality of loads.

20. The method as claimed in claim 19 wherein the current pulse is pulse width modulated.

21. The method as claimed in claim 19 wherein the current pulse is pulse frequency modulated.

22. The method as claimed in claim 19 further comprising the step of directing the charge to each of the plurality of loads on an alternating discharge cycle.

23. The method as claimed in claim 19 further comprising the step of directing the charge to each of the plurality of loads on every discharge cycle.

24. A method of charging a plurality of loads comprising the steps of:

a. storing a first amount of energy in a passive element during a first charging cycle and subsequently storing a second amount of energy in the passive element during a second charging cycle; and

b. sequentially distributing a first portion of the first amount of energy during a first discharging cycle to a first one of the plurality of loads and does not distribute energy to any other load, and sequentially distributing a second portion of the second amount of energy during a second discharging cycle to a second one of the plurality of loads and does not distribute energy to any other load.

25. The method as claimed in claim 24 further comprising the step of directing the first portion of energy to the first one of the plurality of loads through a first load switch and directing the second portion of energy to the second one of the plurality of loads through a second load switch.

26. The method as claimed in claim 25 further comprising the step of preventing extraneous stray energy from escaping through the first load switch and the second load switch by coupling each one of a plurality of diodes in series with the first load switch and in series with the second load switch.

27. The method as claimed in claim 24 further comprising the steps of collecting the first amount of energy based upon a level of voltage across the first one of the plurality of loads prior to the first charging cycle;

and collecting the second amount of energy based upon a level of voltage across the second one of the plurality of loads prior to the second charging cycle.

28. The method as claimed in claim 24 further comprising the steps of collecting the portion of the first amount of energy is based upon a level of voltage across the first one of the plurality of loads during the first discharge cycle;

and collecting the portion of the second amount of energy based upon a level of voltage across the second one of the plurality of loads during the second discharge cycle.

29. The method according to claim 24, wherein the first portion and the second portion are modulated by a pulse width modulation circuit.

30. The method according to claim 24, wherein each load receives a respective regulated DC voltage.

31. A method of charging a plurality of loads having a discharging cycle and a charging cycle comprising the steps of:

a. storing an amount of energy in a passive element; and

b. sequentially distributing a first portion of the amount of energy during the discharging cycle to a first one of the plurality of loads, and sequentially distributing a second portion of the amount of energy during the discharging cycle to a second one of the plurality of loads.

32. The method as claimed in claim 31 further comprising the step of directing the first portion of energy to the first one of the plurality of loads through a first load switch and directing the second portion of energy to the second one of the plurality of loads through a second load switch.

33. The method as claimed in claim 32 further comprising the step of preventing extraneous stray energy from escaping through the first load switch and the second load switch by coupling each one of a plurality of diodes in series with the first load switch and in series with the second load switch.

34. The method as claimed in claim 31 wherein the step of storing collects the amount of energy based upon a level of voltage across the first one of the plurality of loads and based upon a level of voltage across the second one of the plurality of loads prior to the charging cycle.

35. The method as claimed in claim 31 wherein the step of storing further comprising the steps of:

storing the first portion of the amount of energy based upon a level of load voltage across the first one of the plurality of loads prior to the charging cycle; and

storing the second portion of the amount of energy based upon a level of load voltage across the second one of the plurality of loads prior to the charging cycle.

36. The method as claimed in claim 31 wherein the step of storing further comprising the steps of:

storing the first portion of the amount of energy based upon a level of load voltage across the first one of the plurality of loads during the discharging cycle; and

storing the second portion of the amount of energy based upon a level of load voltage across the second one of the plurality of loads during the discharging cycle.

37. The method as claimed in claim 31 wherein the step of distributing the first portion and the second portion further comprises the step of selectively directing one of the following to occur first:

the first portion of the amount of energy directed to the first one of the plurality of loads and the second portion of the amount of energy directed to the second one of the plurality of loads, and wherein the step of selectively directing is in response to voltage levels across the first one and the second one of the plurality of loads.

38. The method as claimed in claim 31 wherein the step of distributing the first portion and the second portion further comprises the step of selectively directing one of the following to occur first:

the first portion of the amount of energy directed to the first one of the plurality of loads and the second portion of the amount of energy directed to the second one of the plurality of loads, and wherein the step of selectively directing is in response to voltage levels across the first one and the second one of the plurality of loads.

39. A circuit for providing multiple output boost regulation for a plurality of loads comprising:

a. a charging means comprising a power source and a passive element to store a charge from the power source;

b. a switching circuit comprising a plurality of switches for connection to each of the plurality of loads and the charging means; and

c. a controller for coordinating the switching circuit to regulate and sequentially direct the charge from the passive element to each of the plurality of loads so that a regulated DC output voltage level is obtained at each of the plurality of loads wherein the controller comprises a pulse frequency modulation circuit.

40. The circuit according to claim 39 wherein the pulse frequency modulation circuit is configured to charge each of the plurality of loads within a same charge cycle of the charging means in response to the predetermined output voltage level.

41. The circuit according to claim 39, wherein each load receives a respective regulated DC voltage.