Bi-directional and adjustable current source

• US 8,384,474 B2
• Filed: 05/10/2011
• Issued: 02/26/2013
• Est. Priority Date: 02/23/2009
• Status: Active Grant

• Current Assignee: Harman International Industries Incorporated (Samsung Electronics Co. Ltd.)
• Original Assignee: Harman International Industries Incorporated (Samsung Electronics Co. Ltd.)
• Inventors: Kolakovic, Mirza, Hamel, Greg, Day, Matthew
• Primary Examiner(s): NGUYEN, PATRICIA T
• Application Number:
  US13/104,023
• Publication Number:
  US 20110304401A1
• Time in Patent Office: 658 Days
• Field of Search: 330/51, 330/302, 330/296
• US Class Current: 330/51
• CPC Class Codes: H03F 1/305 in case of switching on or off of a power supply
• CPC Class Codes: H03F 2200/03 the amplifier being designed for audio applications
• CPC Class Codes: H03F 3/21 with semiconductor devices only H03F3/245 takes precedence

Abstract

A Bi-Directional and Adjustable Current Source (“BACS”) for providing an input voltage to a mute/standby control pin of a power stage integrated circuit (“IC”) of an amplifier input with a voltage signal that is linear, where an output of the BACS and the input to the control pin are shunted with a capacitor, is described. The BACS may include a first switch in signal communication with a high voltage reference and a first current source in signal communication with the first switch. The BACS may also include a second switch in signal communication with a low voltage reference and a second current source in signal communication with the second switch. The BACS may further include a directional current element in signal communication with both the first current source, the second current source, the output of the BACS, the input to the control pin, and the capacitor, where the directional current element is configured to prevent current flow from the output BACS to the first current source.

Claims

1. A Bi-Directional and Adjustable Current Source (“

BACS”

) for providing an input voltage to a mute/standby control pin of a power stage integrated circuit (“

IC”

) of an amplifier input with a voltage signal that is linear, where an output of the BACS and the input to the control pin are shunted with a capacitor, the BACS comprising;

a first switch in signal communication with a high-voltage reference;

a first current source in signal communication with the first switch;

a second switch in signal communication with a low-voltage reference;

a second current source in signal communication with the second switch; and

a directional current element in signal communication with both the first current source, the second current source, the output of the BACS, the input to the control pin, and the capacitor, wherein the directional current element is configured to prevent current flow from the output BACS to the first current source.

2. The BACS of claim 1, wherein the directional current element is a diode.

3. The BACS of claim 1, wherein the first switch includes a transistor configured to act as a switching element.

4. The BACS of claim 3, wherein the first current source includes a transistor configured to act as a current regulator.

5. The BACS of claim 1, wherein the second switch includes a transistor configured to act as a switching element.

6. The BACS of claim 5, wherein the second current source includes a transistor configured to act as a current regulator.

7. A method for providing an input voltage to a mute/standby control pin of a power stage IC of an amplifier input with a voltage signal that is linear utilizing a Bi-Directional and Adjustable Current Source (“

BACS”

) and a shunt capacitor, the method comprising;

generating a first linear voltage signal when the shunt capacitor is charging; and

generating a second linear voltage signal when the shunt capacitor is discharging.

8. The method of claim 7, wherein generating a first linear voltage signal includes providing a charge current from a first current source to the shunt capacitor via a directional current element.

9. The method of claim 8, wherein generating a first linear voltage signal includes utilizing a diode as the directional current element.

10. The method of claim 9, wherein generating a first linear voltage signal includes closing a first switching element in signal communication with the first current source.

11. The method of claim 7, wherein generating a second linear voltage signal includes sinking a discharge current from the shunt capacitor to a second current.

12. The method of claim 11, wherein generating a second linear voltage signal includes closing a second switching element in signal communication with the second current source.

13. A Bi-Directional and Adjustable Current Source (“

BACS”

) for providing an input voltage to a mute/standby control pin of a power stage IC of an amplifier input with a voltage signal that is linear, where an output of the BACS and the amplifier input to the control pin are shunted with a capacitor, the BACS comprising;

means for generating a first linear voltage signal when the shunt capacitor is charging; and

means for generating a second linear voltage signal when the shunt capacitor is discharging.

14. The BACS of claim 13,

wherein the means for generating a second linear voltage signal when the shunt capacitor is discharging includes:

a second switch in signal communication with a low-voltage reference;

a second current source in signal communication with the second switch; and

,

wherein means for generating a first linear voltage signal includes;

a first switch in signal communication with a high-voltage reference;

a first current source in signal communication with the first switch; and

a directional current element in signal communication with both the first current source, the second current source, the output of the BACS, the input to the control pin, and the capacitor, wherein the directional current element is configured to prevent current flow from the output BACS to the first current source.

15. The BACS of claim 14, wherein the directional current element is a diode.

16. The BACS of claim 14, wherein the first switch includes a transistor configured to act as a switching element.

17. The BACS of claim 16, wherein the first current source includes a transistor configured to act as a current regulator.

18. The BACS of claim 14, wherein the second switch includes a transistor configured to act as a switching element.

19. The BACS of claim 18, wherein the second current source includes a transistor configured to act as a current regulator.