Output capacitor current as feedback to control a hysteretic voltage regulator
View Patent ↗A hysteretic voltage regulator is disclosed comprising an inductor having a first end and a second end, wherein the second end is connected to an output capacitor in shunt with a load. A switch connects the first end of the inductor to a supply voltage when an output voltage across the load falls below a reference voltage, and disconnects the first end of the inductor from the supply voltage when a current flowing through the output capacitor rises above a reference current.
1. A hysteretic voltage regulator comprising:
an inductor comprising a first end and a second end, wherein the second end is connected to an output capacitor in shunt with a load such that a first current flows through the output capacitor and a second current flows through the load, wherein the first current does not include the second current; and
a switch operable to connect the first end of the inductor to a supply voltage when an output voltage across the load falls below a reference voltage, and operable to disconnect the first end of the inductor from the supply voltage when the first current rises above a first reference current.
2. The hysteretic voltage regulator as recited in claim 1 , wherein the switch comprises a transistor.
3. The hysteretic voltage regulator as recited in claim 1 , wherein the switch comprises an S/R flip-flop.
4. The hysteretic voltage regulator as recited in claim 1 , further comprising a current sensor operable to sense the first current flowing through the output capacitor.
5. The hysteretic voltage regulator as recited in claim 1 , wherein the switch is further operable to connect the first end of the inductor to the supply voltage when the first current flowing through the output capacitor falls below a second reference current.
6. The hysteretic voltage regulator as recited in claim 4 , wherein the current sensor comprises a sense resistor.
7. The hysteretic voltage regulator as recited in claim 4 , wherein the current sensor comprises:
a voltage detector operable to detect a capacitor voltage across the output capacitor; and
a transform operable to convert the capacitor voltage into the first current flowing through the output capacitor.
8. A data storage device comprising:
a non-volatile memory for storing data received from a host; and
control circuitry including a hysteretic voltage regulator comprising:
an inductor comprising a first end and a second end, wherein the second end is connected to an output capacitor in shunt with a load such that a first current flows through the output capacitor and a second current flows through the load, wherein the first current does not include the second current; and
a switch operable to connect the first end of the inductor to a supply voltage when an output voltage across the load falls below a reference voltage, and operable to disconnect the first end of the inductor from the supply voltage when the first current rises above a first reference current.
9. The data storage device as recited in claim 8 , wherein the switch comprises a transistor.
10. The data storage device as recited in claim 8 , wherein the switch comprises an S/R flip-flop.
11. The data storage device as recited in claim 8 , further comprising a current sensor operable to sense the first current flowing through the output capacitor.
12. The data storage device as recited in claim 8 , wherein the switch is further operable to connect the first end of the inductor to the supply voltage when the first current flowing through the output capacitor falls below a second reference current.
13. The data storage device as recited in claim 8 , wherein the non-volatile memory comprises a semiconductor memory.
14. The data storage device as recited in claim 8 , wherein the non-volatile memory comprises a disk, further comprising a head actuated over the disk.
15. The data storage device as recited in claim 11 , wherein the current sensor comprises a sense resistor.
16. The data storage device as recited in claim 11 , wherein the current sensor comprises:
a voltage detector operable to detect a capacitor voltage across the output capacitor; and
a transform operable to convert the capacitor voltage into the first current flowing through the output capacitor.
17. A method of operating a hysteretic voltage regulator comprising an inductor including a first end and a second end, wherein the second end is connected to an output capacitor in shunt with a load such that a first current flows through the output capacitor and a second current flows through the load, wherein the first current does not include the second current, the method comprising:
connecting the first end of the inductor to a supply voltage when an output voltage across the load falls below a reference voltage; and
disconnecting the first end of the inductor from the supply voltage when the first current rises above a first reference current.
18. The method as recited in claim 17 , further comprising sensing the first current flowing through the output capacitor using a sense resistor.
19. The method as recited in claim 17 , further comprising:
detecting a capacitor voltage across the output capacitor; and
converting the capacitor voltage into the first current flowing through the output capacitor.
20. The method as recited in claim 17 , further comprising connecting the first end of the inductor to the supply voltage when the first current flowing through the output capacitor falls below a second reference current.