CN1300938C

CN1300938C - Quasi push-pull source pole fllower

Info

Publication number: CN1300938C
Application number: CNB2004100138041A
Authority: CN
Inventors: 李连鸣; 黄頲; 王志功
Original assignee: Southeast University
Current assignee: Southeast University
Priority date: 2004-01-05
Filing date: 2004-01-05
Publication date: 2007-02-14
Anticipated expiration: 2024-01-05
Also published as: CN1556586A

Abstract

The present invention relates to a quasi push-pull source electrode tracing device of an analog integrated circuit, the quasi push-pull source electrode tracing device comprises two pairs of transistors, wherein grid electrodes of the first pair of transistors are used as signal input ends, and source electrodes are used as signal output ends; drain electrodes of the first pair of transistors are connected and jointly connected with a power supply; the source electrodes are respectively connected with drain electrodes of the second pair of transistors; grid electrodes of the second pair of transistors are offset on a reference voltage; a third pair of transistors is arranged on the drain electrodes of the second pair of transistors, and the drain electrodes of the second pair of transistors are respectively connected with drain electrodes of the third pair of transistors; the source electrodes of the second pair of transistors and the third pair of transistors are jointly grounded; the grid electrodes and the drain electrodes of the third pair of transistors are connected in a cross mode. The quasi push-pull source electrode tracing device provided by the present invention uses a current reusing technique, namely that a part of current is used to generate transconductance in the third pair of transistors at the falling edge of signals to form dynamic pulling current on the premise of no increase of the power consumption of the power supply; the wavy edge character is effectively improved, and the pendulum rate and the amplitude of output signals are correspondingly increased.

Description

Standard is recommended source follower

(1) technical field

The invention belongs to analog integrated circuit, relate in particular to a kind of standard and recommend source follower.

(2) technical background

Along with the continuous evolution of semiconductor technology, transistor feature size is constantly dwindled at present, considers that from the reliability aspect supply voltage is corresponding constantly to be reduced, to such an extent as to as 1.8V from 5V to 3.3V, at present, this trend still exists.Under low-voltage, obtaining big output signal Slew Rate by traditional source class follower is the comparison difficulty.The problem that the tradition source follower exists is that waveform exists asymmetry at rising, trailing edge, can not produce big output Slew Rate and amplitude simultaneously.At the waveform rising edge, the mutual conductance that first pair of transistor (M1, M2) produces makes signal that rising edge characteristic preferably be arranged.But at trailing edge then because the factor aspect two causes the trailing edge characteristic relatively poor: (1) second pair of transistor (M3, M4) effect is to form current source, with the first pair of transistor (M1, M2) of setovering.But it can not produce dynamic pull-down current, causes waveform drop-down not enough; (2) because all there is the raceway groove mudulation effect usually in transistor, signal makes that more pull-down current is not enough under the effect of effects such as raceway groove modulation in the decline process.This contradiction is constantly dwindled in transistor feature size, becomes more outstanding under the corresponding situation about reducing of supply voltage simultaneously.

(3) technology contents

The standard that technical problem the present invention proposes is recommended source follower, and it can improve the output Slew Rate and the amplitude of signal largely.

A kind of standard that relates to analog integrated circuit of technical scheme is recommended source follower, comprise 2 pairs of transistors, wherein first pair of transistorized grid is as signal input part, source electrode is as signal output part, its drain electrode links to each other and connects power supply jointly, its source electrode joins with second pair of transistor drain respectively, the transistorized grid of this second couple is biased on the reference voltage, on second pair of transistor drain, be provided with the 3rd pair of transistor and second pair of transistor drain is connected with the 3rd pair of transistor drain respectively, the 3rd pair of transistorized grid and the mutual interconnection that drains, and second pair of transistorized source electrode and the 3rd pair of common directly ground connection of transistorized source electrode.

The standard that beneficial effect the present invention proposes is recommended source follower under the prerequisite that does not increase power supply power consumption, utilize electric current huge profit technology, promptly at the signal trailing edge, utilize one part of current to produce mutual conductance at the 3rd pair of transistor, form dynamic pull-down current, the edge characteristic of waveform is effectively improved, correspondingly improved the Slew Rate and the amplitude of output signal.In order to expand the dynamic space of output signal to greatest extent, the 3rd pair of transistorized source electrode and the second pair of direct ground connection of transistorized source electrode, so just farthest reduce the 3rd pair of transistor under the big output signal amplitude of oscillation, leave the possibility of effective working region.The present invention is through checking, and is respond well.

(4) description of drawings

Fig. 1 is a circuit block diagram of the present invention;

Fig. 2 is the embodiments of the invention circuit diagrams.

(5) specific embodiments

A kind of standard that relates to analog integrated circuit is recommended source follower, comprise 2 couples of transistor M1, M2 and M3, M4, first couple of transistor M1 wherein, the grid of M2 is as signal input part, source electrode is as signal output part, its drain electrode links to each other and connects power supply jointly, its source electrode respectively with second couple of transistor M3, the drain electrode of M4 is joined, this second couple of transistor M3, the grid of M4 is biased on the reference voltage Vref, at second couple of transistor M3, the drain electrode of M4 is provided with the 3rd couple of transistor M5, M6, and second couple of transistor M3, the drain electrode of M4 respectively with the 3rd couple of transistor M5, the drain electrode of M6 is connected, the 3rd couple of transistor M5, the grid of M6 and the mutual interconnection of drain electrode, promptly the grid of the pipe M6 in the 3rd pair of transistor joins with the drain electrode of pipe M5, the drain electrode of the grid of transistor M5 and transistor M6 is joined, and second couple of transistor M3, the source electrode of M4 and the 3rd couple of transistor M5, the common directly ground connection of the source electrode of M6, above-mentioned transistor can adopt MOSFET, MESFET or Bipolar etc.

Claims

1, a kind of standard that belongs to analog integrated circuit is recommended source follower, comprise 2 couples of transistor (M1, M2), (M3, M4) and (M5, M6), first couple of transistor (M1, M2) grid is as signal input part, source electrode is as signal output part, first couple of transistor (M1, M2) drain electrode links to each other and connects power supply jointly, its source electrode respectively with second couple of transistor (M3, M4) drain electrode is joined, this second couple of transistor (M3, M4) grid is biased on the reference voltage (Vref), it is characterized in that at second couple of transistor (M3, M4) drain electrode is provided with the 3rd couple of transistor (M5, M6) and second couple of transistor (M3, M4) drain electrode respectively with the 3rd couple of transistor (M5, M6) drain electrode is connected, the 3rd couple of transistor (M5, M6) grid and the mutual interconnection of drain electrode, and second couple of transistor (M3, M4) source electrode and the 3rd couple of transistor (M5, M6) the common directly ground connection of source electrode.