CA1180773A - Differential amplifier with differential to single- ended conversion function - Google Patents
Differential amplifier with differential to single- ended conversion functionInfo
- Publication number
- CA1180773A CA1180773A CA000401606A CA401606A CA1180773A CA 1180773 A CA1180773 A CA 1180773A CA 000401606 A CA000401606 A CA 000401606A CA 401606 A CA401606 A CA 401606A CA 1180773 A CA1180773 A CA 1180773A
- Authority
- CA
- Canada
- Prior art keywords
- fet
- output
- nmos fet
- differential amplifier
- electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/45—Differential amplifiers
- H03F3/45071—Differential amplifiers with semiconductor devices only
- H03F3/45076—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/08—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements
- H03F1/083—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements in transistor amplifiers
- H03F1/086—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements in transistor amplifiers with FET's
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/42—Modifications of amplifiers to extend the bandwidth
- H03F1/48—Modifications of amplifiers to extend the bandwidth of aperiodic amplifiers
- H03F1/483—Modifications of amplifiers to extend the bandwidth of aperiodic amplifiers with field-effect transistors
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Amplifiers (AREA)
Abstract
ABSTRACT
A differential amplifier includes a differential amplifier portion having a first NMOS FET having a gate electrode connected to a first input terminal, a drain electrode providing a first output of said differential amplifier portion and a source electrode. Also included is a second NMOS FET
having a gate electrode connected to a second input terminal, a drain electrode connected to an output terminal for providing a second output of the differential amplifier portion and a source electrode connected to the source electrode of the first NMOS FET. A first load is connected to the drain electrode of the first NMOS FET and a second load is connected to the drain electrode of the second NMOS FET. The differential amplifier includes a differential to single-ended converter portion including a third NMOS FET having drain and gate electrodes for receiving the first output and a source electrode which is grounded. Also included in the differential to single-ended converter portion is a fourth NMOS FET having a drain electrode for receiving the second output, a gate electrode connected to the gate electrode of the third NMOS FET and a source electrode which is grounded. The first and second outputs are converted into one output to be taken out from the output terminal. The device operates over a significantly broader frequency band than similar prior art devices.
A differential amplifier includes a differential amplifier portion having a first NMOS FET having a gate electrode connected to a first input terminal, a drain electrode providing a first output of said differential amplifier portion and a source electrode. Also included is a second NMOS FET
having a gate electrode connected to a second input terminal, a drain electrode connected to an output terminal for providing a second output of the differential amplifier portion and a source electrode connected to the source electrode of the first NMOS FET. A first load is connected to the drain electrode of the first NMOS FET and a second load is connected to the drain electrode of the second NMOS FET. The differential amplifier includes a differential to single-ended converter portion including a third NMOS FET having drain and gate electrodes for receiving the first output and a source electrode which is grounded. Also included in the differential to single-ended converter portion is a fourth NMOS FET having a drain electrode for receiving the second output, a gate electrode connected to the gate electrode of the third NMOS FET and a source electrode which is grounded. The first and second outputs are converted into one output to be taken out from the output terminal. The device operates over a significantly broader frequency band than similar prior art devices.
Description
7'~;3 The present inven~ion relates to a differential amplifier made of N-type MOS (metal oxide semiconductor) field effect transistors and having the differential to single-ended conversion capabllity.
A differential amplifier finds its use in operational (O~ amplifiers, which may be fabricated on a single chip of silicon substra~e using the MOS-integration circuit (IC) technique. This TC technique ena~les t~e integration density for the single chip to be enhanced three to five ~imes as high as that achieved by the bipolar-transistor IC technique.
Field effect transistors (FET's) manufactured by the MOS-IC technique are generally classified into N-type MOS FET's (NMOS PET's), P-type MOS FET's (PMOS FET's), and complementary MOS FET's (CMOS FET's). An NMOS FET is featured by its operational speed, which is nearly three times as high as a PMOS FET.
It has an advantage of permitting a higher degree of circuit integration than a CMOS FET.
An example of the above-mentioned OP-atnplifier made of NMOS FET's is proposed in a paper entitled "Some Design Aspects on M.O.S. L.S~I. Operational Amplifiers" by Bernd Hoefflinger et al., published in the Solid-state and Electron Devices, Vol. 3, No. 2, pp. 33 - ~O~ March 1979 (Reference 1). However, those operational amplifiers proposed therein are operable only within a narrow frequency band for reasons to be described later.
An object of the present invention is, therefore, to provide a dif-ferential amplifier operable over a significantly broader frequency band.
According to the present invention, there is provided a differential amplifier comprising: a differential amplifier portion having a first NMOS FET
having a gate electrode connected to a first input terminal, a drain electrode providing a first OUtp~lt of said differential amplifier portion and a source electrode, a second NMOS FET having a gate electrode connected to a second input ~L15 0~3 terminal, a draiJI electrode connected to an output terminal for providing a second output oF the different;al amplifier portion and a source electrode con-nected to the source electrode of the first NMOS FET, first load means connected to the drain electrode of the first NMOS FET, second load means connected to the drain electrode of the second NMOS FET; and a differential to single-ended con-verter portion including a third NMOS FET having drain and gate ~lectrodes for receiving the first output and a source electrode which is grounded, a fourth NMOS FET having a drain electrode for receiving the second output, a gate elec-trode connected to the gate electrode of the third NMOS FET and a source elec-trode which is grounded, whereby the first and second outputs are converted into one output to be taken out from the output terminal.
This invention will now be described in detail in conjunction with the accompanying drawings in which:
Figure 1 is a circuit diagram of an embodiment of the invention;
Figure 2 shows a graph illustrating the frequency-gain characteristics achieved with the embodiment of the invention and the differential amplifier proposed in Reference l; and Figure 3 shows an example of one application of the present invention.
In the drawings, an FET with a thick line between the source and drain thereof depicts a depletion-type NMOS FET, whereas an FET with a thin line therebetween represents an enhancement-type NMOS FET.
Referring now to Figure 1, one embodiment of the invention comprises a differential amplifier portion having a first FET 3 having the gate electrode connected to a first input terminal 8, and the drain electrode for providing a first output of the amplifier, a second FET 4 having the gate electrode connect-ed to a second input terminal 9, the drain electrode connected to an output ter-mînal 10 for providing a second output of the amplifier. The source electrode
A differential amplifier finds its use in operational (O~ amplifiers, which may be fabricated on a single chip of silicon substra~e using the MOS-integration circuit (IC) technique. This TC technique ena~les t~e integration density for the single chip to be enhanced three to five ~imes as high as that achieved by the bipolar-transistor IC technique.
Field effect transistors (FET's) manufactured by the MOS-IC technique are generally classified into N-type MOS FET's (NMOS PET's), P-type MOS FET's (PMOS FET's), and complementary MOS FET's (CMOS FET's). An NMOS FET is featured by its operational speed, which is nearly three times as high as a PMOS FET.
It has an advantage of permitting a higher degree of circuit integration than a CMOS FET.
An example of the above-mentioned OP-atnplifier made of NMOS FET's is proposed in a paper entitled "Some Design Aspects on M.O.S. L.S~I. Operational Amplifiers" by Bernd Hoefflinger et al., published in the Solid-state and Electron Devices, Vol. 3, No. 2, pp. 33 - ~O~ March 1979 (Reference 1). However, those operational amplifiers proposed therein are operable only within a narrow frequency band for reasons to be described later.
An object of the present invention is, therefore, to provide a dif-ferential amplifier operable over a significantly broader frequency band.
According to the present invention, there is provided a differential amplifier comprising: a differential amplifier portion having a first NMOS FET
having a gate electrode connected to a first input terminal, a drain electrode providing a first OUtp~lt of said differential amplifier portion and a source electrode, a second NMOS FET having a gate electrode connected to a second input ~L15 0~3 terminal, a draiJI electrode connected to an output terminal for providing a second output oF the different;al amplifier portion and a source electrode con-nected to the source electrode of the first NMOS FET, first load means connected to the drain electrode of the first NMOS FET, second load means connected to the drain electrode of the second NMOS FET; and a differential to single-ended con-verter portion including a third NMOS FET having drain and gate ~lectrodes for receiving the first output and a source electrode which is grounded, a fourth NMOS FET having a drain electrode for receiving the second output, a gate elec-trode connected to the gate electrode of the third NMOS FET and a source elec-trode which is grounded, whereby the first and second outputs are converted into one output to be taken out from the output terminal.
This invention will now be described in detail in conjunction with the accompanying drawings in which:
Figure 1 is a circuit diagram of an embodiment of the invention;
Figure 2 shows a graph illustrating the frequency-gain characteristics achieved with the embodiment of the invention and the differential amplifier proposed in Reference l; and Figure 3 shows an example of one application of the present invention.
In the drawings, an FET with a thick line between the source and drain thereof depicts a depletion-type NMOS FET, whereas an FET with a thin line therebetween represents an enhancement-type NMOS FET.
Referring now to Figure 1, one embodiment of the invention comprises a differential amplifier portion having a first FET 3 having the gate electrode connected to a first input terminal 8, and the drain electrode for providing a first output of the amplifier, a second FET 4 having the gate electrode connect-ed to a second input terminal 9, the drain electrode connected to an output ter-mînal 10 for providing a second output of the amplifier. The source electrode
- 2 -~
7~73 of FET 4 is connected to the source electrode of the FET 3. A first load com-prising an FET 1 has its source electrode connected to the drain electrode of the FET 3, and a second load comprising an FET 2 has its source electrode connected to the drain electrode of the second FET 4. The present embodiment also has a differential to single-ended converter portion including a third FET 5 having the drain and gate electrodes for receiving the above-mentioned first output and the source electrode grounded~ a fourth FET 6 having the drain electrode for receiving the above-mentioned second output, the gate electrode connected to the gate electrode of the third FET 5 and the source electrode grounded. The dif-ferential to single-ended converter is adapted to convert the first and second outputs from the differential amplifier portion into one output appearing at the terminal 10. The grounded source electrodes of the FET's 5 and 6 contribute to provide the larger conductance gm for each of the FET's 5 and 6. ~n FET 7 serv-ing as a current source has the gate electrode connected to a direct current (DC) bias voltage source, and the source electrode connected to a voltage source Vss. The drain electrodes of the ~ET's 1 and 2 are commonly connected to a vol-tage source VDD. Since each of the pET's 1, 2, 3, 4 and 7 has the same s~ructure as each of the FET's Tl to T5 described in Figure 5 of Reference 1 mentioned above, further description will be omitted.
With such a structure, voltages Vinl and Vln2 given to the input terminals 8 and 9 are differentially amplified in the FET's 3 and 4 and taken out from the drain electrodes of the PET~s 3 and 4 as differential outputs Vl and V2, respectivel~. The outputs Vl and V2 are converted into a single output VOUt through the FET's 5 and 6 functioning as the above-mentioned single-ended converter and taken out from the terminal 10.
Next, referring to Pigure 2, the reason why the embodiment shown in Figure 1 can operate over a significantly broader frequency band, will be de-scribed below. It is assumed now that the inp~t voltages at the input terminals 1 and 2 are Vi 1 and Vin2, the voltage appearlng at the dra.in electrode of the FET 3 is Vl, the output voltage of the terminal 10 is V0, the currents flowing -from the source VDD to the draln electrodes of the FET's 1 and 2 are Il and I2, the drain currents from the FET's 5 and 6 are I5 and I6, the transconductances o~ the FET's 1 to 6 are gml to gm6, and the backgate conductances of the FET's 1 to 6 are gmbl to g b6. Under the assumption mentioned above, if the input voltage Vinl is equal to ths input voltage Vin2 in operation, the relationship of Vl = V t~ Il, = I2, and I5 = I6 hold. Further, if the length and the width of the gate electrodes of all the PET~s 1 to 6 are identical, the following relation holds between the respective conductances gml to gm6 and gmbl to gmb6 of the FET's 1 to 6:
gml gm2' gm3 gm4' gm5 gm6' gmbl gmb2~ gmb3 gmb4' gmb5 gmb6' The gain A of the amplifier shown in Figure 1, in consideration of those conditions mentioned above, is generally expressed by equat~on A = ~ 2 m3 (1 ~ m5 3 20lgl"l (1 gm5 ~ ~lgml ...... (1) where ~VT
~VSBl VTl: a threshold voltage of the FET 1 VsBl: a voltage between a substrate ~not shown) and the source electrode the FETl formed on the substrate.
Next, if the load capacitance to be produced to the output terminal 10 is assumed to be CLo~ then the frequency characteristic of the gain A may be obtained by equation (2):
(~lgml j L0) gm5 ~lgml ... (2) In the equation (2), if gmS>> gml~ the gain A can be written by equation (4a):
gm3 ~lgml j L0 ,...,. (4a) The cut-off frequency fco at this time is depicted by equation (4b):
fco 2~ C~0 ........................................... (4b) The gain Al of the differential amplifier portion (consisting of the FET's Tl to T~) shown in Figure 5 of Reference 1 is obtained as in equation (5) when each of the FET's Tl to T4 is structurally identical with each of the FET's 1 to 4 used in the invention.
gm3 ~1 gml = jw CLl ................................. (5) wherein CLl denotes the load capacitance of the OUtpllt of the portion ~FET's Tl to T4).
The frequency characteristic of the gain A2 in the differential to single-ended converter portion ~FET's T6 to Tg) (shown in Figure 5 of Reference 1) is then given as follows:
A2 2 g 6 ~ 6) + jw CL2 [ 1 g 6 (1 ~6)~ ( ) wherein CL2 is the load capacitance of the output of the differential to single-ended converter portion (FET's T6 to Tg); and _ aVT6 ~6 avsB6 VT6: a threshold vol*age of the FET T6 VsB6: a voltage between a substrate (not shown)and ~0773 the source electrode of the FET T6 formed on the su~strate.
The cut-off frequencies fCl and fc2 of the differential amplifier shown in Figure 5 of Reference lcan be expressed by equations ~7) and ~8):
cl 2~ CLI ...................................... ~7) f = gm6 ~ ~6) ................................... ~8) For details of each derivation of the above-mentioned equations for the gains A, Al, and A2, and the cut-off frequencies fco~ fCl~ and fC2, refer-ence is made to "Design Consideration in Single-Channel MOS Analog Integrated Circuits - A Tutorial", by Yannis P. Tsividis published in the IEEE Journal of Solid-State Circuits, Vol. SC-13, pp. 383 - 3917 June, 1978 ~Reference 2).
Now turning to Figure 2, the frequency-gain characteristic achieved with the invention (see equation (4 ea)) clearly shows that the present ampli-fier can operate within a considerably broader frequency band. This is easily confirmed from the fact that the present amplifier has a larger zero-crossing frequency fOl ~at which the gain is O dB) than a corresponding one fo2 of Ref-erence 1.
The differential amplifier of the present invention, designed on the basis of the structure of Figure 1 to have a maximum gain of 30 dB, has a cut-off frequency fco (equation (4b~) of 30 KHz and a zero-crossing frequency fOl ~equation (4a)) of 1 MHz. On the other hand, the differential amplifier accord-ing to Reference 1 has a cut-off frequency f 1 (equa~ion (7)) of 30 KHz, a cut-off frequency fc2 (equation (8)) of 200 KHz, and a zero-crossing frequency fo2 (equation (6)) of 500 KHz, when designed to achieve the same gain.
Referring to Figure 3 which shows an application of the invention, ~.18~'73 an OP-amplifier comprises the difEerential amplifier 100 shown in Figure 1, a second stage 200 for amplifying the output of the amplifier 100, and an output stage 300 for performing the class A push-pull operation. The second stage 200 includes an FET 10 to form a negative feedback amplifier; an FET 9 serving as the load resistance of the FET 10; a capacitor for frequency compensation of the negative feedback amplifier; and an FET 8 serving as a resistance element for preventing the reduction of frequency band width. The output stage 300, on the other hand, has FET's 17 and 18 to function as a class A push-pull amplifier, and a Mirror circuit composed of FET's 13 and 16 for giving a signal of a phase opposite to the input signal appearing at the FET 17 to the FET 18. An FET 12 functions as a resistance element, whereas an FET 15 is used to lower the output impedance of the FET 18 by feeding back the output of the FET 18 to the input thereof.
Since the operation of the OP-amplifier of Figure 3 is similar to that of the OP-amplifier shown in Figure 5 of Reference 1 except that the OP-amplifi-er of Figure 3 can operate within a comparatively broader frequency band, a detailed description will be omitted.
7~73 of FET 4 is connected to the source electrode of the FET 3. A first load com-prising an FET 1 has its source electrode connected to the drain electrode of the FET 3, and a second load comprising an FET 2 has its source electrode connected to the drain electrode of the second FET 4. The present embodiment also has a differential to single-ended converter portion including a third FET 5 having the drain and gate electrodes for receiving the above-mentioned first output and the source electrode grounded~ a fourth FET 6 having the drain electrode for receiving the above-mentioned second output, the gate electrode connected to the gate electrode of the third FET 5 and the source electrode grounded. The dif-ferential to single-ended converter is adapted to convert the first and second outputs from the differential amplifier portion into one output appearing at the terminal 10. The grounded source electrodes of the FET's 5 and 6 contribute to provide the larger conductance gm for each of the FET's 5 and 6. ~n FET 7 serv-ing as a current source has the gate electrode connected to a direct current (DC) bias voltage source, and the source electrode connected to a voltage source Vss. The drain electrodes of the ~ET's 1 and 2 are commonly connected to a vol-tage source VDD. Since each of the pET's 1, 2, 3, 4 and 7 has the same s~ructure as each of the FET's Tl to T5 described in Figure 5 of Reference 1 mentioned above, further description will be omitted.
With such a structure, voltages Vinl and Vln2 given to the input terminals 8 and 9 are differentially amplified in the FET's 3 and 4 and taken out from the drain electrodes of the PET~s 3 and 4 as differential outputs Vl and V2, respectivel~. The outputs Vl and V2 are converted into a single output VOUt through the FET's 5 and 6 functioning as the above-mentioned single-ended converter and taken out from the terminal 10.
Next, referring to Pigure 2, the reason why the embodiment shown in Figure 1 can operate over a significantly broader frequency band, will be de-scribed below. It is assumed now that the inp~t voltages at the input terminals 1 and 2 are Vi 1 and Vin2, the voltage appearlng at the dra.in electrode of the FET 3 is Vl, the output voltage of the terminal 10 is V0, the currents flowing -from the source VDD to the draln electrodes of the FET's 1 and 2 are Il and I2, the drain currents from the FET's 5 and 6 are I5 and I6, the transconductances o~ the FET's 1 to 6 are gml to gm6, and the backgate conductances of the FET's 1 to 6 are gmbl to g b6. Under the assumption mentioned above, if the input voltage Vinl is equal to ths input voltage Vin2 in operation, the relationship of Vl = V t~ Il, = I2, and I5 = I6 hold. Further, if the length and the width of the gate electrodes of all the PET~s 1 to 6 are identical, the following relation holds between the respective conductances gml to gm6 and gmbl to gmb6 of the FET's 1 to 6:
gml gm2' gm3 gm4' gm5 gm6' gmbl gmb2~ gmb3 gmb4' gmb5 gmb6' The gain A of the amplifier shown in Figure 1, in consideration of those conditions mentioned above, is generally expressed by equat~on A = ~ 2 m3 (1 ~ m5 3 20lgl"l (1 gm5 ~ ~lgml ...... (1) where ~VT
~VSBl VTl: a threshold voltage of the FET 1 VsBl: a voltage between a substrate ~not shown) and the source electrode the FETl formed on the substrate.
Next, if the load capacitance to be produced to the output terminal 10 is assumed to be CLo~ then the frequency characteristic of the gain A may be obtained by equation (2):
(~lgml j L0) gm5 ~lgml ... (2) In the equation (2), if gmS>> gml~ the gain A can be written by equation (4a):
gm3 ~lgml j L0 ,...,. (4a) The cut-off frequency fco at this time is depicted by equation (4b):
fco 2~ C~0 ........................................... (4b) The gain Al of the differential amplifier portion (consisting of the FET's Tl to T~) shown in Figure 5 of Reference 1 is obtained as in equation (5) when each of the FET's Tl to T4 is structurally identical with each of the FET's 1 to 4 used in the invention.
gm3 ~1 gml = jw CLl ................................. (5) wherein CLl denotes the load capacitance of the OUtpllt of the portion ~FET's Tl to T4).
The frequency characteristic of the gain A2 in the differential to single-ended converter portion ~FET's T6 to Tg) (shown in Figure 5 of Reference 1) is then given as follows:
A2 2 g 6 ~ 6) + jw CL2 [ 1 g 6 (1 ~6)~ ( ) wherein CL2 is the load capacitance of the output of the differential to single-ended converter portion (FET's T6 to Tg); and _ aVT6 ~6 avsB6 VT6: a threshold vol*age of the FET T6 VsB6: a voltage between a substrate (not shown)and ~0773 the source electrode of the FET T6 formed on the su~strate.
The cut-off frequencies fCl and fc2 of the differential amplifier shown in Figure 5 of Reference lcan be expressed by equations ~7) and ~8):
cl 2~ CLI ...................................... ~7) f = gm6 ~ ~6) ................................... ~8) For details of each derivation of the above-mentioned equations for the gains A, Al, and A2, and the cut-off frequencies fco~ fCl~ and fC2, refer-ence is made to "Design Consideration in Single-Channel MOS Analog Integrated Circuits - A Tutorial", by Yannis P. Tsividis published in the IEEE Journal of Solid-State Circuits, Vol. SC-13, pp. 383 - 3917 June, 1978 ~Reference 2).
Now turning to Figure 2, the frequency-gain characteristic achieved with the invention (see equation (4 ea)) clearly shows that the present ampli-fier can operate within a considerably broader frequency band. This is easily confirmed from the fact that the present amplifier has a larger zero-crossing frequency fOl ~at which the gain is O dB) than a corresponding one fo2 of Ref-erence 1.
The differential amplifier of the present invention, designed on the basis of the structure of Figure 1 to have a maximum gain of 30 dB, has a cut-off frequency fco (equation (4b~) of 30 KHz and a zero-crossing frequency fOl ~equation (4a)) of 1 MHz. On the other hand, the differential amplifier accord-ing to Reference 1 has a cut-off frequency f 1 (equa~ion (7)) of 30 KHz, a cut-off frequency fc2 (equation (8)) of 200 KHz, and a zero-crossing frequency fo2 (equation (6)) of 500 KHz, when designed to achieve the same gain.
Referring to Figure 3 which shows an application of the invention, ~.18~'73 an OP-amplifier comprises the difEerential amplifier 100 shown in Figure 1, a second stage 200 for amplifying the output of the amplifier 100, and an output stage 300 for performing the class A push-pull operation. The second stage 200 includes an FET 10 to form a negative feedback amplifier; an FET 9 serving as the load resistance of the FET 10; a capacitor for frequency compensation of the negative feedback amplifier; and an FET 8 serving as a resistance element for preventing the reduction of frequency band width. The output stage 300, on the other hand, has FET's 17 and 18 to function as a class A push-pull amplifier, and a Mirror circuit composed of FET's 13 and 16 for giving a signal of a phase opposite to the input signal appearing at the FET 17 to the FET 18. An FET 12 functions as a resistance element, whereas an FET 15 is used to lower the output impedance of the FET 18 by feeding back the output of the FET 18 to the input thereof.
Since the operation of the OP-amplifier of Figure 3 is similar to that of the OP-amplifier shown in Figure 5 of Reference 1 except that the OP-amplifi-er of Figure 3 can operate within a comparatively broader frequency band, a detailed description will be omitted.
Claims
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A differential amplifier comprising: a differential amplifier portion having a first NMOS FET having a gate electrode connected to a first input ter-minal, a drain electrode providing a first output of said differential amplifier portion and a source electrode, a second NMOS FET having a gate electrode con-nected to a second input terminal, a drain electrode conneted to an output ter-minal for providing a second output of the differential amplifier portion and a source electrode connected to the source electrode of the first NMOS FET, first load means connected to the drain electrode of the first NMOS FET, second load means connected to the drain electrode of the second NMOS FET; and a differen-tial to single-ended converter portion including a third NMOS FET having drain and gate electrodes for receiving the first output and a source electrode which is grounded, a fourth NMOS FET having a drain electrode for receiving the second output, a gate electrode connected to the gate electrode of the third NMOS FET
and a source electrode which is grounded, whereby the first and second outputs are converted into one output to be taken out from the output terminal.
and a source electrode which is grounded, whereby the first and second outputs are converted into one output to be taken out from the output terminal.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63663/1981 | 1981-04-27 | ||
| JP56063663A JPS57178408A (en) | 1981-04-27 | 1981-04-27 | Differential amplifying circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1180773A true CA1180773A (en) | 1985-01-08 |
Family
ID=13235802
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000401606A Expired CA1180773A (en) | 1981-04-27 | 1982-04-26 | Differential amplifier with differential to single- ended conversion function |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS57178408A (en) |
| CA (1) | CA1180773A (en) |
| DE (1) | DE3215661A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3668739D1 (en) * | 1985-03-06 | 1990-03-08 | Fujitsu Ltd | COMPARATOR CIRCUIT WITH IMPROVED OUTPUT CHARACTERISTICS. |
| FR2592538B1 (en) * | 1985-12-31 | 1988-02-12 | Radiotechnique Compelec | HIGH FREQUENCY DIFFERENTIAL AMPLIFIER STAGE AND AMPLIFIER COMPRISING SAME. |
| US5392000A (en) * | 1993-11-09 | 1995-02-21 | Motorola, Inc. | Apparatus and method for frequency compensating an operational amplifier |
| AU2002310348A1 (en) * | 2001-06-11 | 2002-12-23 | Johns Hopkins University | Low-power, differential optical receiver in silicon on insulator |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3873933A (en) * | 1973-11-08 | 1975-03-25 | Rca Corp | Circuit with adjustable gain current mirror amplifier |
| JPS5132257A (en) * | 1974-09-13 | 1976-03-18 | Hitachi Ltd | |
| US4188588A (en) * | 1978-12-15 | 1980-02-12 | Rca Corporation | Circuitry with unbalanced long-tailed-pair connections of FET's |
-
1981
- 1981-04-27 JP JP56063663A patent/JPS57178408A/en active Pending
-
1982
- 1982-04-26 CA CA000401606A patent/CA1180773A/en not_active Expired
- 1982-04-27 DE DE19823215661 patent/DE3215661A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| DE3215661A1 (en) | 1982-12-16 |
| JPS57178408A (en) | 1982-11-02 |
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