Apparatus for radio telecommunication system and method of building up output power

• US 7,366,481 B2
• Filed: 04/03/2007
• Issued: 04/29/2008
• Est. Priority Date: 05/31/2002
• Status: Expired due to Fees

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Renesas Technology Corporation (Renesas Electronics Corporation), Tipcom Limited
• Inventors: Wurm, Patrick, Okada, Kazuhisa, Hikasa, Kazuhiko
• Primary Examiner(s): VO, NGUYEN THANH
• Application Number:
  US11/730,585
• Publication Number:
  US 20070238424A1
• Time in Patent Office: 392 Days
• Field of Search: 455/126, 455/127.2, 455/127.1, 455/102, 455/108, 455/110, 375/300, 375/302, 332/145, 332/149, 332/144
• US Class Current: 455/126
• CPC Class Codes: H03F 1/0205 in transistor amplifiers
• CPC Class Codes: H03F 1/30 Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters in differential amplifiers H03F3/45479
• CPC Class Codes: H03F 1/32 Modifications of amplifiers to reduce non-linear distortion by negative feedback H03F1/34
• CPC Class Codes: H03F 2200/294 the amplifier being a low noise amplifier [LNA]
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2200/513 the amplifier being made for low supply voltages
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H03G 3/3047 for intermittent signals, e.g. burst signals
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04L 27/2017 in which the phase changes are non-linear, e.g. generalized and Gaussian minimum shift keying, tamed frequency modulation H04L27/201 takes precedence
• CPC Class Codes: H04L 27/2071 in which the data are represented by the carrier phase, e.g. systems with differential coding
• CPC Class Codes: H04L 27/361 Modulation using a single or unspecified number of carriers, e.g. with separate stages of phase and amplitude modulation

Abstract

A polar loop based radio telecommunication apparatus which has a phase control loop for controlling the phase of a carrier outputted from an oscillator for transmitter, and an amplitude control loop for controlling the amplitude of a transmission output signal outputted from a power amplifier circuit, wherein precharge means is provided on a forward path from a current source, through the power amplifier circuit, to a detection circuit, forming the amplitude control loop, for rapidly increasing a control voltage for the power amplifier circuit to a power threshold upon starting transmission.

Claims

1. A radio communication apparatus comprising:

a base band unit which generates signals to be transmitted;

a modulator which modulates the signals;

a phase detector which detects a phase component of the signals modulated by the modulator;

an amplitude detector which detects an amplitude component of the signal modulated by said modulator;

an oscillator which generates a transmission signal in accordance with an output of the phase detector;

a power amplifier which amplifies the transmission signal;

a feedback path which supplies an output level instruction signal of the power amplifier circuit to the amplitude detector; and

a forward path which supplies an output of the amplitude detector to the power amplifier for control of an amplitude of the transmission signal;

wherein the forward path includes a loop filter which generates a voltage in response to the output of the amplitude detector;

a first amplifier which amplifies the voltage;

a charge pump circuit which includes a capacitor, a current source for charging said capacitor, a current sink for discharging a charge on said capacitor, and which is configured to operate the current source and the current sink in response to an output of the first amplifier to accumulate a charge on the capacitor; and

a precharge unit which is arranged between the first amplifier and the power amplifier and which is capable of rapidly increasing a control voltage by charging the capacitor for the power amplifier to a power threshold on starting transmission.

2. A radio communication apparatus according to claim 1, further comprising:

a level detector which detects the output level instruction signal,

wherein the precharge unit includes a precharge current source and switch circuit connected in series with the precharge current source,

wherein the switch circuit is configured to be turned on when the power amplifier starts transmission, and the switch circuit is turned off in accordance with an output of the level detector.

3. A radio communication apparatus according to claim 1, further comprising a timer circuit,

wherein the precharge operation of the precharge unit is terminated at an earlier one of timing of detection of lapse of a predetermined time measured by the timer circuit after the precharge unit starts the precharge operation, and timing of changing of the output of the level detector.

4. A radio communication apparatus according to claim 3, wherein the precharge current source is turned off when said timer circuit instructs the precharge unit to terminate the precharge operation.