Title:
POWER AMPLIFIER AND METHOD FOR PROTECTING THE POWER AMPLIFIER FROM DAMAGE CAUSED BY THERMAL OVERLOAD
Document Type and Number:
Japanese Patent JPH05251948
Kind Code:
A
Abstract:
PURPOSE: To prevent an output signal from being cut off or distorted even at high ambient temperature or when the size of an energy consuming body is small by representing the maximum permissible amplitude of the output signal with a 1st electric reference quantity varying in amplitude with tempera ture. CONSTITUTION: The output side of an amplification stage 1 is connected to an input terminal 6 of a range comparator 7, and reference voltages VR1 and VR2 are applied to other two input terminals 8 and 9 of the range comparator 7. The reference voltages VR1 and VR2 vary in value with the temperature of the amplification stage 1 and indicate the minimum permissible value and maximum permissible value of an output voltage VO at specific temperature. If the output signal VO exceeds the range determined by the reference voltages VR1 and VR2 , the range comparator 7 generates an output signal (s) of specific level, which is filtered by a low-pass filter and integrated, and then interpreted as a gain decrease instruction by a variable gain element 5.
Inventors:
EDOARUDO BOTSUTEI
KURAUDEIO TABUAZAANI
KURAUDEIO TABUAZAANI
Application Number:
JP28002792A
Publication Date:
September 28, 1993
Filing Date:
October 19, 1992
Export Citation:
Assignee:
SGS THOMSON MICROELECTRONICS
International Classes:
H03F1/30; H03F3/20; H03G3/20; H03G3/30; H03F1/52; H03G5/16; (IPC1-7): H03F1/52; H03F3/20; H03G3/30; H03G5/16
Attorney, Agent or Firm:
Soga Doteru (6 people outside)