Reference voltage adjustment,申请号US19990476036-传众专利搜索

Reference voltage adjustment

申请公布号：US6281734(B1)

申请号：US19990476036

申请日期：1999.12.31

申请公布日期：2001.08.28

申请人：

STMICROELECTRONICS, INC.

发明人：MCCLURE DAVID C.;YIN RONG

分类号：G05F3/24;(IPC1-7):H03L5/00

主分类号：G05F3/24

摘要：A reference voltage trim circuit includes a voltage follower receiving the reference voltage to be trimmed, with one or more resistive loads providing predefined voltage shifts serially connected between the output of the voltage follower and the output of the trim circuit. The voltage follower includes a current mirror differential amplifier receiving the reference voltage at one input and the output of the voltage follower at the other input, and a transistor with a resistive load connected between the power supply voltages and receiving the output of the current mirror differential amplifier at the transistor's gate. The resistive loads provide varying preselected voltage drop and are each shunted by corresponding fuses, with the entire series of resistive loads shunted by a master fuse. To trim the reference voltage, at least the master fuse is blown, together with the fuse(s) shunting resistive loads which combine to result in the desired trim voltage. Pass gates control which end of the resistive load series is connected to the output of the voltage follower and which is connected to the output of the trim circuit. To decrement the reference voltage, a first end is connected to the output of the voltage follower and the second end is connected to trim circuit output; to increment the reference voltage, the second end of the resistive load series is connected to the voltage follower output and the first end is connected to the trim circuit output.