Granted Patent B1

US 8,717,699 · App. 13/347,562 · Granted May 6, 2014

Abstract

Claims (79)

1. A voltage booster comprising:

an input for receiving an input voltage Vin;

a first charging capacitor C 1 ;

a second charging capacitor C 2 ;

an output capacitor Cout; and

control circuitry operable to charge the output capacitor Cout to four times Vin by:

connecting C 1 in parallel with Vin to charge C 1 to Vin;

after charging C 1 to Vin, connecting C 2 in parallel with Vin plus C 1 to charge C 2 to twice Vin;

after charging C 2 to twice Vin, connecting C 1 in parallel with Vin to recharge C 1 to Vin; and

after recharging C 1 , connecting Cout in parallel with Vin plus C 1 plus C 2 to charge Cout to four times Vin.

2. The voltage booster as recited in claim 1 , wherein the control circuitry is further operable to charge the output capacitor Cout to three times Vin by:

connecting C 1 in parallel with Vin to charge C 1 to Vin;

connecting C 2 in parallel with Vin to charge C 2 to Vin; and

after charging C 1 and C 2 to Vin, connecting Cout in parallel with Vin plus C 1 plus C 2 to charge Cout to three times Vin.

3. The voltage booster as recited in claim 2 , wherein Vin is a voltage with respect to a reference node, the voltage booster further comprising:

a first switch operable to connect C 1 to Vin and a second switch operable to connect C 1 to the reference node; and

the second switch and a third switch operable to connect C 2 to Vin and a fourth switch operable to connect C 2 to the reference node.

4. The voltage booster as recited in claim 2 , wherein Vin is a voltage with respect to a reference node, the voltage booster further comprising:

a single first switch operable to connect C 1 to Vin and a single second switch operable to connect C 1 to the reference node; and

a single third switch operable to connect C 2 to Vin and a single fourth switch operable to connect C 2 to the reference node.

5. A disk drive comprising:

a disk;

a head actuated over the disk; and

a voltage booster configurable into a first mode to boost a supply voltage (SV) by N and configurable into a second mode to boost a backup voltage (BV) by M greater than N; and

control circuitry operable to:

configure the voltage booster into the first mode during normal operation; and

configure the voltage booster into the second mode during a power failure.

6. The disk drive as recited in claim 5 , wherein the control circuitry is operable to configure the voltage booster into the second mode after the backup voltage decays below a threshold during the power failure.

7. The disk drive as recited in claim 5 , wherein N equals three and M equals four.

8. The disk drive as recited in claim 7 , wherein the voltage booster comprises a first charging capacitor C 1 , a second charging capacitor C 2 , and an output capacitor Cout, wherein the control circuitry is operable to charge the output capacitor Cout to four times BV by:

connecting C 1 in parallel with BV to charge C 1 to BV;

connecting C 2 in parallel with BV plus C 1 to charge C 2 to twice BV;

after charging C 2 to twice BV, connecting C 1 in parallel with BV to recharge C 1 to BV; and

after recharging C 1 , connecting Cout in parallel with BV plus C 1 plus C 2 to charge Cout to four times BV.

9. The disk drive as recited in claim 8 , wherein the control circuitry is further operable to charge the output capacitor Cout to three times SV by:

connecting C 1 in parallel with SV to charge C 1 to VS;

connecting C 2 in parallel with SV to charge C 2 to VS; and

after charging C 1 and C 2 to SV, connecting Cout in parallel with SV plus C 1 plus C 2 to charge Cout to three times SV.

10. The disk drive as recited in claim 9 , wherein VS is a voltage with respect to a reference node, the voltage booster further comprising:

a first switch operable to connect C 1 to VS and a second switch operable to connect C 1 to the reference node; and

the second switch and a third switch operable to connect C 2 to VS and a fourth switch operable to connect C 2 to the reference node.

11. The disk drive as recited in claim 9 , wherein VS is a voltage with respect to a reference node, the voltage booster further comprising:

a single first switch operable to connect C 1 to VS and a single second switch operable to connect C 1 to the reference node; and

a single third switch operable to connect C 2 to VS and a single fourth switch operable to connect C 2 to the reference node.

12. A method of operating a voltage booster, the voltage booster comprising an input for receiving an input voltage Vin, a first charging capacitor C 1 , a second charging capacitor C 2 , and an output capacitor Cout, the method comprising charging the output capacitor Cout to four times Vin by:

connecting C 1 in parallel with Vin to charge C 1 to Vin;

after charging C 1 to Vin, connecting C 2 in parallel with Vin plus C 1 to charge C 2 to twice Vin;

after charging C 2 to twice Vin, connecting C 1 in parallel with Vin to recharge C 1 to Vin; and

after recharging C 1 , connecting Cout in parallel with Vin plus C 1 plus C 2 to charge Cout to four times Vin.

13. The method as recited in claim 12 , further comprising charging the output capacitor Cout to three times Vin by:

connecting C 1 in parallel with Vin to charge C 1 to Vin;

connecting C 2 in parallel with Vin to charge C 2 to Vin; and

after charging C 1 and C 2 to Vin, connecting Cout in parallel with Vin plus C 1 plus C 2 to charge Cout to three times Vin.

14. The method as recited in claim 13 , wherein Vin is a voltage with respect to a reference node, the method further comprising:

connecting C 1 to Vin through a first switch and connecting C 1 to the reference node through a second switch; and

connecting C 2 to Vin through the second switch and a third switch and connecting C 2 to the reference node through a fourth switch.

15. The method as recited in claim 13 , wherein Vin is a voltage with respect to a reference node, the method further comprising:

connecting C 1 to Vin through a single first switch and connecting C 1 to the reference node through a single second switch; and

connecting C 2 to Vin through a single third switch and connecting C 2 to the reference node through a single fourth switch.

16. A method of operating a disk drive comprising, the disk drive comprising a disk, a head actuated over the disk, and a voltage booster configurable into a first mode to boost a supply voltage (SV) by N and configurable into a second mode to boost a backup voltage (BV) by M greater than N, the method comprising:

configuring the voltage booster into the first mode during normal operation; and

configuring the voltage booster into the second mode during a power failure.

17. The method as recited in claim 16 , further comprising configuring the voltage booster into the second mode after the backup voltage decays below a threshold during the power failure.

18. The method as recited in claim 16 , wherein N equals three and M equals four.

19. The method as recited in claim 18 , wherein the voltage booster comprises a first charging capacitor C 1 , a second charging capacitor C 2 , and an output capacitor Cout, the method further comprising charging the output capacitor Cout to four times BV by:

connecting C 1 in parallel with BV to charge C 1 to BV;

connecting C 2 in parallel with BV plus C 1 to charge C 2 to twice BV;

after charging C 2 to twice BV, connecting C 1 in parallel with BV to recharge C 1 to BV; and

after recharging C 1 , connecting Cout in parallel with BV plus C 1 plus C 2 to charge Cout to four times BV.

20. The method as recited in claim 19 , further comprising charging the output capacitor Cout to three times SV by:

connecting C 1 in parallel with SV to charge C 1 to VS;

connecting C 2 in parallel with SV to charge C 2 to VS; and

after charging C 1 and C 2 to SV, connecting Cout in parallel with SV plus C 1 plus C 2 to charge Cout to three times SV.

21. The method as recited in claim 20 , wherein VS is a voltage with respect to a reference node, the method further comprising:

connecting C 1 to Vin through a first switch and connecting C 1 to the reference node through a second switch; and

connecting C 2 to Vin through the second switch and a third switch and connecting C 2 to the reference node through a fourth switch.

22. The method as recited in claim 20 , wherein VS is a voltage with respect to a reference node, the method further comprising:

connecting C 1 to Vin through a single first switch and connecting C 1 to the reference node through a single second switch; and

connecting C 2 to Vin through a single third switch and connecting C 2 to the reference node through a single fourth switch.

Assignments (8)