Title:
VOLTAGE FOLLOWER OPERATIONAL AMPLIFIER
Document Type and Number:
Japanese Patent JPH1141037
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To suppress an increase in offset voltage while securing a wide output voltage range by providing a back gate-source voltage limiting means which is inserted and connected between the commonconnected source and common- connected back gate of two P channel type MOS transistors. SOLUTION: A 4th N channel MOS transistor MN4 is connected as the back gate-source voltage limiting means between the back gate and source of the 1st and 2nd P channel type MOS transistors MP1 and MP2. The transistor MN4 limits the back gate-source voltage VBS of the transistors MP1 and MP2. At this time, respective constants are so set that an increment in the voltage VBS of the transistors MP1 and MP2 caused by the voltage VBS of the transistor MN4 is a voltage sufficient to drive a 3rd N channel MOS transistor MN3. Consequently, the voltage VBS becomes constant even when the source voltage is set high.
Inventors:
ITO MOTOHIRO
Application Number:
JP19001297A
Publication Date:
February 12, 1999
Filing Date:
July 15, 1997
Export Citation:
Assignee:
TOSHIBA CORP
International Classes:
G06G7/12; H03F3/45; H03F3/50; (IPC1-7): H03F3/45; G06G7/12; H03F3/50
Attorney, Agent or Firm:
Kazuo Sato (3 others)