CA1140223A - Voltage-to-current converter - Google Patents
Voltage-to-current converterInfo
- Publication number
- CA1140223A CA1140223A CA000323376A CA323376A CA1140223A CA 1140223 A CA1140223 A CA 1140223A CA 000323376 A CA000323376 A CA 000323376A CA 323376 A CA323376 A CA 323376A CA 1140223 A CA1140223 A CA 1140223A
- Authority
- CA
- Canada
- Prior art keywords
- amplifier
- input
- power supply
- voltage
- output
- 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
- 230000004044 response Effects 0.000 claims description 7
- 230000001105 regulatory effect Effects 0.000 claims description 6
- 238000001228 spectrum Methods 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 5
- 230000033228 biological regulation Effects 0.000 description 3
- 239000003990 capacitor Substances 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 230000003466 anti-cipated effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- JXSJBGJIGXNWCI-UHFFFAOYSA-N diethyl 2-[(dimethoxyphosphorothioyl)thio]succinate Chemical compound CCOC(=O)CC(SP(=S)(OC)OC)C(=O)OCC JXSJBGJIGXNWCI-UHFFFAOYSA-N 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 238000012806 monitoring device Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 229940061319 ovide Drugs 0.000 description 1
- 230000004962 physiological condition Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/30—Single-ended push-pull [SEPP] amplifiers; Phase-splitters therefor
- H03F3/3069—Single-ended push-pull [SEPP] amplifiers; Phase-splitters therefor the emitters of complementary power transistors being connected to the output
- H03F3/3071—Single-ended push-pull [SEPP] amplifiers; Phase-splitters therefor the emitters of complementary power transistors being connected to the output with asymmetrical driving of the end stage
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
- G05F1/10—Regulating voltage or current
- G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
- G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
- G05F1/561—Voltage to current converters
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G1/00—Control arrangements or circuits, of interest only in connection with cathode-ray tube indicators; General aspects or details, e.g. selection emphasis on particular characters, dashed line or dotted line generation; Preprocessing of data
- G09G1/04—Deflection circuits ; Constructional details not otherwise provided for
-
- 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
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K6/00—Manipulating pulses having a finite slope and not covered by one of the other main groups of this subclass
- H03K6/02—Amplifying pulses
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
- H04N3/10—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical
- H04N3/16—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by deflecting electron beam in cathode-ray tube, e.g. scanning corrections
- H04N3/18—Generation of supply voltages, in combination with electron beam deflecting
- H04N3/185—Maintaining dc voltage constant
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Signal Processing (AREA)
- Automation & Control Theory (AREA)
- Multimedia (AREA)
- Electromagnetism (AREA)
- Remote Sensing (AREA)
- Computer Hardware Design (AREA)
- Theoretical Computer Science (AREA)
- Amplifiers (AREA)
- Control Of Voltage And Current In General (AREA)
- Dc-Dc Converters (AREA)
Abstract
Abstract A voltage-to-current converter with improved power supply rejection ratio including output operational amplifier means to substantially supply the power requirements of a load, the output operational amplifier being powered by an unregulated power supply. the output of the operational amplifier is supplied to the load at a predetermined gain which may be symbolized by a feedback loop Z2/Z1 This output operational amplifier is supplied by an additional low-power, high-gain amplifier having very good power supply rejection ratio. The input amplifier has high gain at DC and up to the power supply frequency and including the first few harmonics thereof.
The input amplifier is stabilized at high frequency by the provision of a feedback loop which limits the gain of the input amplifier at high frequencies. the feedback loop, however, is 50 designed as to not inter era with the DC and low frequency gain of the amplifier.
The input amplifier is stabilized at high frequency by the provision of a feedback loop which limits the gain of the input amplifier at high frequencies. the feedback loop, however, is 50 designed as to not inter era with the DC and low frequency gain of the amplifier.
Description
2~3 Background Of The Invention This invention relates to power supplies for electronic apparatus as a voltage-to-current converter for driving the yoke (e.g. Y-axis) of a cathode ray tube.
In electronic applications involving operational amplifiers, there is often a requirement that the output voltage or current bear a precise relationship to the input voltage or current. This is particularly true when the electronic appli-cations are included in scientific instruments wherein electrical signals representative of various physiological conditions are processed, recorded and/or displayed.
In such applications, it is conyentional to include regulated power supplies from which these yarious operational amplifiers are powered in order to proyide precise co~relation of input to output. It should be appreciated, however? that the inclusion of such regulated power supplies? firstly increases the cost of the apparatus within which they are included, secondly increases the overall power requirements of the apparatus and thirdly, since power is dissipated in these deyices, complicates the power/heat dissipation requirements in those instances where the generation of heat is of concern. The latter is common in many solid state applications.
The measure of sensitiyity of an amplifier to variations in its supply voltage is known as the power supply rejection ratio. More specifically~ the power supply rejection ratio is the ratio of change in input-offset voltage of an operational amplifier, to the change in power supply yoltage that causes the change in input-offset yoltaget I have determined that by ~easurably improying the power supply rejection ratio of an amplifier or amplifier system, ~. .7 / 1 `~
an operational amplifier may be provided which is primarily powered from an unregulated source. Yet the operational amplifier may be utilized in demanding drive~ situations such as providing the signal to a yoke in a cathode ray tube.
Summary of the Invention A voltage-to-current converter with improved power supply rejection ratio including output operatlonal amplifier means to substantially supply the power requirements of a load, the output operational amplifier being powered by an unregulated power supply. The output of the operational amplifier is supplied to the load at a predetermined gain which may be symbolized by a feedback loop Z2Jzl- This output operational amplifier is supplied by an additional low-power, high-gain amplifier having very good power supply rejection ratio. The input amplifier has high gain at DC
and up to the power supply frequency and including the first few harmonics thereof.
The input amplifier is stabilized at high frequency by the provision of a feedback loop which limits the gain of the input amplifier at high frequencies. The feedback loop, however, is so designed as to not interfere with the DC
and low frequency gain of the amplifier.
Additional adjustment of the overall frequency response of the two amplifier system may be accomplished ! with the inclusion of resistance-capacitance coupling.
Specifically, the invention relates to a voltage-to-current converter for supplying regulated current to a load from a substantially unrcgulated supply comprising an output amplifier supplied by an unregulated power supply r~ mb/~ ~ 3 ~
and having a current output at least equal to the current requirements of the load and an input amplifier having an input and output and having a power supply rejection ratio at least equal to the required power supply rejection ratio of the voltage-to-current converter, and a gain of at least the order of magnitude of the ratio of the power supply rejection ratio of the output amplifier and required power supply rejection ratio of the voltage-to-current converter which gain extends at least to the first harmonics of the frequency spectrum of the output amplifiers power supply, the input amplifier further having a feedback loop having a resistance Rl connected from the load to the input of the input amplifier, Rl being of a value substantially equal to the input impedance to the voltage-to-current converter, and further having a feedback loop from the output of the input amplifier to input of the input amplifier containing a resistance R2 to control the high frequency gain of the input àmplifier and a capacitance Cl to maximize the frequency gain of the input amplifier and an input resistor R3 and input capacitance C2 which corrects the overall frequency response of the voltage-to-current converter introduced by R2 and Cl.
Description of the Drawings Figure 1 is a schematic diagram of a conventional circuit including an amplifier driving a load.
Figure 2 is a schematic diagram of an alternative view of the circuit of Figure 1 for the purposes of under-standing the present invention.
~ ~ .
mb/J, - 3a -Figure 3 is a schematic diagram of a circuit illus-trating the present invention~
Figure 4 is a circuit diagram of a specific circuit illustrating the invention.
- Description of the Preferred Embodiments Referring now to the drawings and in particular Fig. 1, the diagram and circuit represents a conventional view of an operational amplifier supplying a load L. By traditional notation, the output current I equals the input yoltage Yi divided by the shunt resistance r .
I = in rS
The load L supplied by the amplifier A is connected in series with the shunt resistance rsO A feedback loop F is provided through which the necessary current regulation is effected as is well understood in the art. The input signal to the operational amplifier is supplied by the signal generatdr Yi with an input impedance represented by resistance Rg. As previously mentioned, if there is to be a high degree of correlation of input and output irrespectlve of fluctuation of line or power supply voltage, a regulated power supply may necessarily be included to power the amplifier.
For the purposes of analysis in understanding the present invention, the circuit of Fig. 1 may be thought of as illustrated in Fig. 2 wherein the operational amplifier may be viewed as two amplifiers Al and A2. Amplifier A2 is designated the "output" amplifier and is of a size selected to proyide the power necessary to supply the load over the full anticipated range of operation. It is viewed as having some known forward f~"~ - 4 -` 114~i2Z3 gain as may be symbolized by Zl and Z2. For the purposes of the prc~sent invention, the output amplifier is operated from an unregulated power supply. This operation of the amplifier by unregulated supply is according to the objectives of the invention as previously specified.
Amplifier Al is designated an "input~' amplifier and is designed to provide additional gain at low power and is further designed to reflect optimum power supply rejection ratio.
Such low-power, well-regulated amplifiers are known in the art.
lQ In order to p~ovide oyerall system xegulation and take advantage of the large power output nonregulated amplifier A2? a gain of Al is made as large as possible in the oyerall frequency band of the power supply, namely, from DC up to line frequency and including the principal harmonicst As may be seen in Fig. 2, the overall current regulation of the system is proyided through Al as an input to A2. Thus? it may be viewed that ~1 functions to provide the regulation power necessary to make up fox the degree of unregulation of power amplifier A2.
The preferred circuit for accomplishin~ the electrical philosophy as described above is illustrated in Fig. 3 It will be observed that seyeral of the components of the ci~cuit in Fig. 3 have already been discussed, namely, Vin? Rg? Xs~
amplifiers Al and A2, the load L and the feedback loop setting the gain of A2, namely Zl and Z2. The circuit of Fig. 3 includes also a feedback loop including resistances Rl and R2 and capacitor Cl to provide loop stability. This is accomplished by reducing the gain of amplifier Al at high frequency to prevent oscillation. The values of the components are selected also to promote low fre~uency gain of the amplifier, namely, cg/j~' .
~14(}223 to provide a low frequency gain substantially equal to the open loop gain of Al. Additionally, the overall frequency response of the Al-A2 system is adjusted by the inclusion of the network R3C2 to provide uniform frequency response of the amplifier combination ~AlA2).
In the illustrated embodiment in Fig. 3, the values of the resistances and capacitances are computed as indicated to bring about the electrical objectives of the circuit, namely, R2=R3, Cl=C2 and Rl=Rg.
Figure 4 illustrates an actual circuit for driving the Y-axis yoke of a cathode ray/tube in a patient monitoring display. As is traditional in electronic applications.
Amplifiers Al and A2 are made up of a number of individual components, each providing necessary characteristics previously described to the identifiable input and output amplifiers.
The input terminal for the circuit is labeled V
in and constitutes the output of earlier stages of physiological sensors and preamplifiers. Consistent with Fig. 3, the input impedance is illustrated at Rg to which the frequency compen-sating elements R3 and C2 are connected. In the pre~erred embodiment illustrated in Figure 4, R3 is approximately 18 kilo ohms (17.8k) and C2 has a value of about 0.02 microfarads (0.~22md).
Amplifier Al in the illustrated embodiment is made up of four stages, 20, 22, 24 and 26, three of which (20, 22 and 24) are in an integrated circuit AC3096AE, stage 20 being an NPN pair of transistors and stage 22 an PNP pair and stage 24 a single NPN transistor. Stage 26 is a pair of TD-201 base-coupled transistors through a pair of MSD7000 diodes to the power supply. Resistance 28 is approximately 1 kilo ohm and resistance 30 cg/~
~14Q223 is approximately 2 kilo ohms. The base of stage 26 is coupled through resistor 32 which is approximately 2 kilo ohms. A
clamping diode 34 which is a lN914 is connected to the base of stage 24. Resistors 35 and 36 are approximately 2 kilo ohms being used to connect the emitters of stage 22 to their power supply. Capacitor 38 is added to adjust the frequency response of amplifier Al and is approximately 100 picofarads. Likewise, capacitor 40 (10 picofarads) and resistor 42 (1 kilo ohm) are added to adjust frequency response of the amplifierO The output of amplifier Al is indicated at terminal 44 and the feedback therefrom including previously described R2 resistance in the present embodiment being approximately 18 kilo ohms and the capacitance C1 being approximately 0O02 microfarads to the negative input of amplifier Al. Clamping diodes 46 (MSD7000 and 48 (IN914) may be added to improve overload stability of the amplifier.
Amplifier A2 is also composed of four stages, 50, 52, 54 and 56. Stage 50 is composed of two NPN-type transistors in an emitter-coupled configuration, being connected to its bias voltage through resistor 58 while ha~ing a value of approxi-matèly 1 k ohms, and to stage 52 th~ough a TlS98 NPN transistor 51. Stage 52 is a PNP transistor of the type MPSU60 being connected through its emitter to its plus bias through resistor 60 being approximately 70 ohms (68.5). The base of this transistor is clamped to the bias through a pair of lN914 diodes. Stage 54 an MPSU10 transistor, is emitter connected to the bias through coupling resistor 64 being approximately 150 ohms. Stages 52 and 54 supply stage 56 which is a pair of MPSU10 and MPSU60 transistors supplied through transistors 57, a TIS98, with the cg/l' ~L~4(~;~23 - - .
diodes at 72 and 74 being MSD7000's and resistor 78 being approximately 1 kilo ohm and resistor 80 being approximately 1.5 kilo ohms. Resistors 82 and 84 are low value approximately one ohm. The resistors are included for stabilization on the output of stage 56 indicated at terminal 86, which in the monitoring device will be coupled to the Y-yoke axis of the cathode ray tube. Zl and Z2 representing the forward gain of the output amplifier illustrated and Z2 has a value of approxi-mately 80K ohms and Zl of A approximately 400 ohms.
It must be appreciated that various modifications and adaptations to the illustrated circuitry may be made to achieve particular operating characteristics as desired. It should be further appreciated, however, that such modifications and additions as may fall within the scope of the appended claims must be considered as within the full spirit and scope of the invention herein described.
cg/~`~
.
In electronic applications involving operational amplifiers, there is often a requirement that the output voltage or current bear a precise relationship to the input voltage or current. This is particularly true when the electronic appli-cations are included in scientific instruments wherein electrical signals representative of various physiological conditions are processed, recorded and/or displayed.
In such applications, it is conyentional to include regulated power supplies from which these yarious operational amplifiers are powered in order to proyide precise co~relation of input to output. It should be appreciated, however? that the inclusion of such regulated power supplies? firstly increases the cost of the apparatus within which they are included, secondly increases the overall power requirements of the apparatus and thirdly, since power is dissipated in these deyices, complicates the power/heat dissipation requirements in those instances where the generation of heat is of concern. The latter is common in many solid state applications.
The measure of sensitiyity of an amplifier to variations in its supply voltage is known as the power supply rejection ratio. More specifically~ the power supply rejection ratio is the ratio of change in input-offset voltage of an operational amplifier, to the change in power supply yoltage that causes the change in input-offset yoltaget I have determined that by ~easurably improying the power supply rejection ratio of an amplifier or amplifier system, ~. .7 / 1 `~
an operational amplifier may be provided which is primarily powered from an unregulated source. Yet the operational amplifier may be utilized in demanding drive~ situations such as providing the signal to a yoke in a cathode ray tube.
Summary of the Invention A voltage-to-current converter with improved power supply rejection ratio including output operatlonal amplifier means to substantially supply the power requirements of a load, the output operational amplifier being powered by an unregulated power supply. The output of the operational amplifier is supplied to the load at a predetermined gain which may be symbolized by a feedback loop Z2Jzl- This output operational amplifier is supplied by an additional low-power, high-gain amplifier having very good power supply rejection ratio. The input amplifier has high gain at DC
and up to the power supply frequency and including the first few harmonics thereof.
The input amplifier is stabilized at high frequency by the provision of a feedback loop which limits the gain of the input amplifier at high frequencies. The feedback loop, however, is so designed as to not interfere with the DC
and low frequency gain of the amplifier.
Additional adjustment of the overall frequency response of the two amplifier system may be accomplished ! with the inclusion of resistance-capacitance coupling.
Specifically, the invention relates to a voltage-to-current converter for supplying regulated current to a load from a substantially unrcgulated supply comprising an output amplifier supplied by an unregulated power supply r~ mb/~ ~ 3 ~
and having a current output at least equal to the current requirements of the load and an input amplifier having an input and output and having a power supply rejection ratio at least equal to the required power supply rejection ratio of the voltage-to-current converter, and a gain of at least the order of magnitude of the ratio of the power supply rejection ratio of the output amplifier and required power supply rejection ratio of the voltage-to-current converter which gain extends at least to the first harmonics of the frequency spectrum of the output amplifiers power supply, the input amplifier further having a feedback loop having a resistance Rl connected from the load to the input of the input amplifier, Rl being of a value substantially equal to the input impedance to the voltage-to-current converter, and further having a feedback loop from the output of the input amplifier to input of the input amplifier containing a resistance R2 to control the high frequency gain of the input àmplifier and a capacitance Cl to maximize the frequency gain of the input amplifier and an input resistor R3 and input capacitance C2 which corrects the overall frequency response of the voltage-to-current converter introduced by R2 and Cl.
Description of the Drawings Figure 1 is a schematic diagram of a conventional circuit including an amplifier driving a load.
Figure 2 is a schematic diagram of an alternative view of the circuit of Figure 1 for the purposes of under-standing the present invention.
~ ~ .
mb/J, - 3a -Figure 3 is a schematic diagram of a circuit illus-trating the present invention~
Figure 4 is a circuit diagram of a specific circuit illustrating the invention.
- Description of the Preferred Embodiments Referring now to the drawings and in particular Fig. 1, the diagram and circuit represents a conventional view of an operational amplifier supplying a load L. By traditional notation, the output current I equals the input yoltage Yi divided by the shunt resistance r .
I = in rS
The load L supplied by the amplifier A is connected in series with the shunt resistance rsO A feedback loop F is provided through which the necessary current regulation is effected as is well understood in the art. The input signal to the operational amplifier is supplied by the signal generatdr Yi with an input impedance represented by resistance Rg. As previously mentioned, if there is to be a high degree of correlation of input and output irrespectlve of fluctuation of line or power supply voltage, a regulated power supply may necessarily be included to power the amplifier.
For the purposes of analysis in understanding the present invention, the circuit of Fig. 1 may be thought of as illustrated in Fig. 2 wherein the operational amplifier may be viewed as two amplifiers Al and A2. Amplifier A2 is designated the "output" amplifier and is of a size selected to proyide the power necessary to supply the load over the full anticipated range of operation. It is viewed as having some known forward f~"~ - 4 -` 114~i2Z3 gain as may be symbolized by Zl and Z2. For the purposes of the prc~sent invention, the output amplifier is operated from an unregulated power supply. This operation of the amplifier by unregulated supply is according to the objectives of the invention as previously specified.
Amplifier Al is designated an "input~' amplifier and is designed to provide additional gain at low power and is further designed to reflect optimum power supply rejection ratio.
Such low-power, well-regulated amplifiers are known in the art.
lQ In order to p~ovide oyerall system xegulation and take advantage of the large power output nonregulated amplifier A2? a gain of Al is made as large as possible in the oyerall frequency band of the power supply, namely, from DC up to line frequency and including the principal harmonicst As may be seen in Fig. 2, the overall current regulation of the system is proyided through Al as an input to A2. Thus? it may be viewed that ~1 functions to provide the regulation power necessary to make up fox the degree of unregulation of power amplifier A2.
The preferred circuit for accomplishin~ the electrical philosophy as described above is illustrated in Fig. 3 It will be observed that seyeral of the components of the ci~cuit in Fig. 3 have already been discussed, namely, Vin? Rg? Xs~
amplifiers Al and A2, the load L and the feedback loop setting the gain of A2, namely Zl and Z2. The circuit of Fig. 3 includes also a feedback loop including resistances Rl and R2 and capacitor Cl to provide loop stability. This is accomplished by reducing the gain of amplifier Al at high frequency to prevent oscillation. The values of the components are selected also to promote low fre~uency gain of the amplifier, namely, cg/j~' .
~14(}223 to provide a low frequency gain substantially equal to the open loop gain of Al. Additionally, the overall frequency response of the Al-A2 system is adjusted by the inclusion of the network R3C2 to provide uniform frequency response of the amplifier combination ~AlA2).
In the illustrated embodiment in Fig. 3, the values of the resistances and capacitances are computed as indicated to bring about the electrical objectives of the circuit, namely, R2=R3, Cl=C2 and Rl=Rg.
Figure 4 illustrates an actual circuit for driving the Y-axis yoke of a cathode ray/tube in a patient monitoring display. As is traditional in electronic applications.
Amplifiers Al and A2 are made up of a number of individual components, each providing necessary characteristics previously described to the identifiable input and output amplifiers.
The input terminal for the circuit is labeled V
in and constitutes the output of earlier stages of physiological sensors and preamplifiers. Consistent with Fig. 3, the input impedance is illustrated at Rg to which the frequency compen-sating elements R3 and C2 are connected. In the pre~erred embodiment illustrated in Figure 4, R3 is approximately 18 kilo ohms (17.8k) and C2 has a value of about 0.02 microfarads (0.~22md).
Amplifier Al in the illustrated embodiment is made up of four stages, 20, 22, 24 and 26, three of which (20, 22 and 24) are in an integrated circuit AC3096AE, stage 20 being an NPN pair of transistors and stage 22 an PNP pair and stage 24 a single NPN transistor. Stage 26 is a pair of TD-201 base-coupled transistors through a pair of MSD7000 diodes to the power supply. Resistance 28 is approximately 1 kilo ohm and resistance 30 cg/~
~14Q223 is approximately 2 kilo ohms. The base of stage 26 is coupled through resistor 32 which is approximately 2 kilo ohms. A
clamping diode 34 which is a lN914 is connected to the base of stage 24. Resistors 35 and 36 are approximately 2 kilo ohms being used to connect the emitters of stage 22 to their power supply. Capacitor 38 is added to adjust the frequency response of amplifier Al and is approximately 100 picofarads. Likewise, capacitor 40 (10 picofarads) and resistor 42 (1 kilo ohm) are added to adjust frequency response of the amplifierO The output of amplifier Al is indicated at terminal 44 and the feedback therefrom including previously described R2 resistance in the present embodiment being approximately 18 kilo ohms and the capacitance C1 being approximately 0O02 microfarads to the negative input of amplifier Al. Clamping diodes 46 (MSD7000 and 48 (IN914) may be added to improve overload stability of the amplifier.
Amplifier A2 is also composed of four stages, 50, 52, 54 and 56. Stage 50 is composed of two NPN-type transistors in an emitter-coupled configuration, being connected to its bias voltage through resistor 58 while ha~ing a value of approxi-matèly 1 k ohms, and to stage 52 th~ough a TlS98 NPN transistor 51. Stage 52 is a PNP transistor of the type MPSU60 being connected through its emitter to its plus bias through resistor 60 being approximately 70 ohms (68.5). The base of this transistor is clamped to the bias through a pair of lN914 diodes. Stage 54 an MPSU10 transistor, is emitter connected to the bias through coupling resistor 64 being approximately 150 ohms. Stages 52 and 54 supply stage 56 which is a pair of MPSU10 and MPSU60 transistors supplied through transistors 57, a TIS98, with the cg/l' ~L~4(~;~23 - - .
diodes at 72 and 74 being MSD7000's and resistor 78 being approximately 1 kilo ohm and resistor 80 being approximately 1.5 kilo ohms. Resistors 82 and 84 are low value approximately one ohm. The resistors are included for stabilization on the output of stage 56 indicated at terminal 86, which in the monitoring device will be coupled to the Y-yoke axis of the cathode ray tube. Zl and Z2 representing the forward gain of the output amplifier illustrated and Z2 has a value of approxi-mately 80K ohms and Zl of A approximately 400 ohms.
It must be appreciated that various modifications and adaptations to the illustrated circuitry may be made to achieve particular operating characteristics as desired. It should be further appreciated, however, that such modifications and additions as may fall within the scope of the appended claims must be considered as within the full spirit and scope of the invention herein described.
cg/~`~
.
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A voltage-to-current converter for supplying regulated current to a load from a substantially unregulated supply comprising an output amplifier supplied by an unregulated power supply and having a current output at least equal to the current requirements of the load and an input amplifier having an input and output and having a power supply rejection ratio at least equal to the required power supply rejection ratio of said voltage-to-current converter, and a gain of at least the order of magnitude of the ratio of the power supply rejection ratio of the output amplifier and required power supply rejection ratio of the voltage-to-current converter which gain extends at least to the first harmonics of the frequency spectrum of said output amplifiers power supply, said input amplifier further having a feedback loop having a resistance R1 connected from said load to the input of the input amplifier, R1 being of a value substantially equal to the input impedance to the voltage-to-current converter, and further having a feedback loop from the output of the input amplifier to input of the input amplifier containing a resistance R2 to control the high frequency gain of the input amplifier and a capacitance C1 to maximize the frequency gain of the input amplifier and an input resistor R3 and input capacitance C2 which corrects the overall frequency response of the voltage-to-current converter introduced by R2 and C1.
2. The voltage-to-current converter of claim 1 wherein R2 is substantially equal to R3.
3. The voltage-to-current converter of claim 2 wherein C1 substantially equals C2.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US89590178A | 1978-04-13 | 1978-04-13 | |
| US895,901 | 1978-04-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1140223A true CA1140223A (en) | 1983-01-25 |
Family
ID=25405255
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000323376A Expired CA1140223A (en) | 1978-04-13 | 1979-03-14 | Voltage-to-current converter |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1140223A (en) |
| GB (1) | GB2019148A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2500689A3 (en) * | 1981-02-20 | 1982-08-27 | Faiveley Sa | Unidirectional regulated current source for medical treatment - uses amplifier with feedback to regulate current supplied by amplifier to within precise limits |
| EP0608938A1 (en) * | 1993-01-27 | 1994-08-03 | Philips Composants | Amplifier with differential input stage and integrated stabilisation capacitor |
| EP1119907B1 (en) * | 1999-07-28 | 2007-12-26 | Nxp B.V. | Method of and arrangement for converting voltage to current |
-
1979
- 1979-03-14 CA CA000323376A patent/CA1140223A/en not_active Expired
- 1979-03-20 GB GB7909805A patent/GB2019148A/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| GB2019148A (en) | 1979-10-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |