Power control circuit, semiconductor device and transceiver circuit using the same

• US 20080305756A1
• Filed: 08/07/2008
• Published: 12/11/2008
• Est. Priority Date: 11/22/2004
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Renesas Technology Corporation (Renesas Electronics Corporation)
• Inventors: Tanaka, Satoshi, Kuriyama, Akira
• Granted Patent: US 8,213,888 B2
• Time in Patent Office: Days
• US Class Current: 455/127.2
• CPC Class Codes: H03G 3/02 Manually-operated control H03G3/001 and H03G3/002 take precedence
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04
• CPC Class Codes: H03G 3/3047 for intermittent signals, e.g. burst signals

Abstract

There is provided a power control circuit having a stable high-speed operation, and a semiconductor device and a transceiver circuit using it. The power control circuit controls the gain of an amplifier so that power outputted from the amplifier reaches a desired value according to a digital control signal. The power control circuit includes a digital feedback loop which converts a detected signal obtained by detecting a value of the output power of the amplifier to a digital signal, determines a differential between the digital signal and the digital control signal, converts the differential to an analog signal and outputs a first feedback signal, an analog feedback loop which outputs a high frequency element corresponding to a differential between an analog signal to which the digital control signal is converted and the detected signal, as a second feedback signal, and an adder which determines the sum of the first and the second feedback signal and outputs a gain control signal for controlling the gain of the amplifier.

Claims

1. A power control circuit that controls a gain of an amplifier in such a manner that output power of the amplifier reaches a desired power value according to a power control signal, comprising:

a digital feedback loop which converts a detected signal obtained by detecting a power value of the output power of the amplifier to a digital signal, determines a first differential between the detected signal converted to the digital signal and the power control signal, and converts the first differential to a first analog signal and outputs a first feedback signal;

an analog feedback loop which outputs a high frequency element of a second differential between the power control signal converted to a second analog signal and the detected signal as a second feedback signal; and

an adder which determines the sum of the first feedback signal and the second feedback signal and outputs a gain control signal for controlling the gain of the amplifier.