Controller and Method for Using a DC-DC Converter in a Mobile Handset

• US 20080220826A1
• Filed: 03/07/2008
• Published: 09/11/2008
• Est. Priority Date: 03/09/2007
• Status: Active Grant

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Skyworks Solutions Incorporated
• Inventors: Rozenblit, Dmitriy, Ku, Man H., Dagher, Elias, Juan, Kevin
• Granted Patent: US 8,019,293 B2
• Time in Patent Office: Days
• US Class Current: 455/572
• 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 in a bypass mode comprises coupling the DC-DC converter to a battery.

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

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

5. The method of claim 4, further comprising:

waiting a desired time for the peak detector to settle.

6. The method of claim 5, wherein waiting a desired time comprises using an adjustable delay element.

7. The method of claim 5, wherein waiting a desired time comprises waiting for a predetermined time.

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

9. The method of claim 8, 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.

10. 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 comprises commanding the DC-DC converter in response to a pedestal voltage.

11. The method of claim 10, wherein the pedestal voltage is associated with a regulator input signal.

12. The method of claim 1, wherein using the series of peak voltages to determine a target voltage further comprises limiting the voltage gap between the battery voltage and the target voltage.

13. The method of claim 1, further comprising:

using the steps of commanding, enabling, detecting, determining and commanding 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 comprises an offset for determining a target voltage that is higher than a function of the series of peak voltages.

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 comprises a signal condition indicative of an end of the transmission burst.

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