Title:
OUTPUT STAGE FOR OPERATIONAL AMPLIFIER
Document Type and Number:
Japanese Patent JPH02288607
Kind Code:
A
Abstract:
PURPOSE: To drive a small load while reducing the power consumption of an operational amplifier by increasing an output supply current as a function of the load while holding an electric power drain low. CONSTITUTION: Assuming that the value of a resistor 50 is small in a halt operation state, a power source increase circuit 44 operates a current mirror to supply a low halt bias current to the collector of a transistor(TR) 46. In supply operation mode, the current increase circuit 44 detects a load current, i.e., the collector-emitter current of a TR 42 and supplies a current which increases in level as a load current request increases to the base of the TR 42. Therefore, the load current can be supplied which is large enough to drive a small load of, for example, <=600 ohm. Consequently, the small load can be driven while the consumption of halt electric power is held small.
Inventors:
DEIBITSUDO EMU SUSATSUKU
ROBAATO REONARUDO BAIN
ROBAATO REONARUDO BAIN
Application Number:
JP8930190A
Publication Date:
November 28, 1990
Filing Date:
April 05, 1990
Export Citation:
Assignee:
MOTOROLA INC
International Classes:
H03F3/45; H03F1/02; H03F3/30; (IPC1-7): H03F3/45
Attorney, Agent or Firm:
Yoshiaki Ikeuchi
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