Controller and method for using a DC-DC converter in a mobile handset

• US 8,019,293 B2
• Filed: 03/07/2008
• Issued: 09/13/2011
• Est. Priority Date: 03/09/2007
• Status: Expired due to Fees

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Skyworks Solutions Incorporated
• Inventors: Ku, Man H., Dagher, Elias, Juan, Kevin, Rozenblit, Dmitriy
• Primary Examiner(s): VO, NGUYEN THANH
• Application Number:
  US12/044,203
• Publication Number:
  US 20080220826A1
• Time in Patent Office: 1,285 Days
• Field of Search: 455571-572, 455/574, 455/127.1, 455/127.2, 455/127.5, 455/108
• US Class Current: 455/127.1
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

A controller enables the integration of a DC-DC converter in an amplitude modulation power control loop in a mobile handset. The controller includes an input conditioner and an event sensor. The input conditioner uses a peak detector to track the output of a regulator and responds to available baseband input signals. The event sensor controls a switch that connects the DC-DC converter to a battery in response to a bypass event. The controller bypasses the DC-DC-converter when a transmitter is not enabled. The DC-DC converter is enabled prior to a transmission burst. A target voltage is determined from a series of detected peak voltages from the output of the regulator. The controller commands the DC-DC converter to transition to the target voltage until the end of a transmission burst.

Claims

1. A method for using a DC-DC converter in a mobile handset, comprising:

applying a DC-DC converter between a voltage source and a regulator in a power amplifier amplitude modulation control loop, the regulator having an output configured to control an input voltage to the power amplifier;

commanding the DC-DC converter in a bypass mode when a transmitter is not enabled;

enabling the DC-DC converter in response to a control signal that initiates a transmission burst;

detecting a series of peak voltages from a regulator output;

determining a target voltage in response to the series of peak voltages;

commanding the DC-DC converter to transition to the target voltage; and

commanding the DC-DC converter to the bypass mode in response to a signal that indicates an end of the transmission burst.

2. The method of claim 1, wherein commanding the DC-DC converter to the bypass mode includes coupling the DC-DC converter to a battery, the battery providing a battery voltage.

3. The method of claim 2, wherein using the series of peak voltages to determine a target voltage further includes limiting the voltage gap between the battery voltage and the target voltage.

4. The method of claim 1, wherein enabling the DC-DC converter includes responding to a transmitter switch signal.

5. The method of claim 1, wherein detecting a series of peak voltages from the regulator output includes coupling the output of the regulator to a peak detector.

6. The method of claim 5, further comprising:

waiting a desired time for the peak detector to settle.

7. The method of claim 6, wherein waiting a desired time includes using an adjustable delay element.

8. The method of claim 6, wherein waiting a desired time includes waiting for a predetermined time.

9. The method of claim 1, wherein determining a target voltage in response to the series of peak voltages includes determining a target voltage that is higher than a function of the series of peak voltages.

10. The method of claim 9, further comprising:

commanding the DC-DC converter to the bypass mode when a magnitude of a peak in the regulator output voltage exceeds the target voltage.

11. The method of claim 1, wherein commanding the DC-DC converter to the bypass mode in response to a signal that indicates an end of the transmission burst includes commanding the DC-DC converter in response to a pedestal voltage.

12. The method of claim 11, wherein the pedestal voltage is associated with a regulator input signal.

13. The method of claim 1, further comprising:

using the steps of commanding the DC-DC converter in a bypass mode, enabling, detecting, determining and commanding the DC-DC converter to transition to the target voltage to communicate a multi-slot transmission burst with amplitude modulation.

14. A controller for using a DC-DC converter in an amplitude modulation power control loop in a mobile handset, the controller comprising:

an input conditioner coupled in series between a regulator and the DC-DC converter, the input conditioner including a peak detector responsive to the output of the regulator and a mode selector responsive to input signals from a baseband subsystem; and

an event sensor that produces a switch control signal that couples the DC-DC converter to a battery in response to a bypass event.

15. The controller of claim 14, wherein the input conditioner further includes an offset for determining a target voltage that is higher than a function of a series of peak voltages detected by the peak detector.

16. The system of claim 15, wherein the bypass event comprises a peak voltage that exceeds the target voltage.

17. The system of claim 15, wherein the bypass event includes a signal condition indicative of an end of a transmission burst.

18. The controller of claim 14, wherein the input conditioner further includes a low-voltage limiter configured to limit the voltage gap between the battery voltage and a target voltage.

19. The controller of claim 14, further comprising:

a switching node for controlling the frequency of the output from the DC-DC converter.

20. The controller of claim 14, wherein the mode selector is responsive to an under voltage lockout detector.