CN107017876B - High-frequency program-controlled capacitive impedance circuit and measuring device - Google Patents
High-frequency program-controlled capacitive impedance circuit and measuring device Download PDFInfo
- Publication number
- CN107017876B CN107017876B CN201610054843.9A CN201610054843A CN107017876B CN 107017876 B CN107017876 B CN 107017876B CN 201610054843 A CN201610054843 A CN 201610054843A CN 107017876 B CN107017876 B CN 107017876B
- Authority
- CN
- China
- Prior art keywords
- current source
- capacitive impedance
- terminal
- frequency
- triode
- 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.)
- Active
Links
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K19/00—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits
- H03K19/02—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits using specified components
- H03K19/08—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits using specified components using semiconductor devices
- H03K19/094—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits using specified components using semiconductor devices using field-effect transistors
- H03K19/0944—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits using specified components using semiconductor devices using field-effect transistors using MOSFET or insulated gate field-effect transistors, i.e. IGFET
Abstract
The invention provides a high-frequency program-controlled capacitive impedance circuit and a measuring device, wherein the high-frequency program-controlled capacitive impedance circuit comprises at least one high-frequency capacitive impedance unit, and the high-frequency capacitive impedance unit comprises: the signal input end of the program-controlled amplifier is used as the signal input end of the high-frequency capacitive impedance unit, and the output end of the capacitor is used as the signal output end of the high-frequency capacitive impedance unit. By utilizing the invention, the influence of the on-resistance and parasitic capacitance of the switching element of the program-controlled capacitive impedance circuit in the prior art can be reduced, and the high-frequency performance of the program-controlled capacitive impedance circuit is improved.
Description
Technical Field
The invention relates to the technical field of measurement, in particular to a high-frequency range capacitive impedance control circuit and a measurement device.
Background
In circuit structures such as filters, amplifier feedback networks, etc., capacitive impedance elements are often required, which typically use capacitors. If the frequency characteristics of the filter and amplifier feedback network need to be adjusted, a programmable capacitive impedance circuit, such as: in integrated circuit systems, since the initial error of the capacitance is relatively large, in order to obtain the desired capacitive impedance, the magnitude of the capacitive impedance needs to be adjusted during the production and use of the integrated circuit, which requires a programmable capacitive impedance circuit.
Fig. 1 is a prior art programmable capacitive impedance circuit. The terminal a and the terminal B are signal terminals of a capacitive impedance circuit, and a circuit between the two terminals has a capacitive impedance characteristic. PMOS (P-type insulated gate field effect transistor), M1, and a fixed capacitor C1 (capacitor C1) are connected in series to form a program-controlled capacitive impedance unit, PMOS M2 and capacitor C2 are connected in series to form another program-controlled capacitive impedance unit, and the two program-controlled capacitive impedance units are connected in parallel to form a program-controlled capacitive impedance circuit.
Terminal E1 and terminal E2 are control terminals of the programmable capacitive impedance circuit. When the potential of the control end is more than or equal to the level of the terminal A and the level of the terminal B, the PMOS connected with the control end is cut off; when the control terminal potential is lower than the terminal A or the terminal B level by more than one threshold voltage, the PMOS is conducted.
When the PMOS M1 is cut off and the PMOS M2 is cut off, the capacitor C1 and the capacitor C2 are disconnected from the path of the terminal A, and no capacitive impedance characteristic exists between the terminals A and B; when the PMOS M1 is on and the PMOS M2 is off, the capacitor C1 is connected with the passage of the terminal A, the capacitor C2 is disconnected with the passage of the terminal A, and the capacitive impedance between the terminals A and B is equal to the capacitive impedance of the capacitor C1; when the PMOS M1 is cut off and the PMOS M2 is turned on, the capacitor C1 is disconnected with the passage of the terminal A, the capacitor C2 is connected with the passage of the terminal A, and the capacitive impedance between the terminals A and B is equal to the capacitive impedance of the capacitor C2; when the PMOS M1 is turned on and the PMOS M2 is also turned on, the paths of the capacitor C1 and the capacitor C2 and the terminal a are both turned on, and the capacitive impedance between the terminal a and the terminal B is equal to the sum of the capacitive impedances of the capacitor C1 and the capacitor C2.
As described above, by changing the levels of the terminal E1 and the terminal E2 so that the capacitor C1 or the capacitor C2 is turned on or off with the path of the terminal a, the magnitude of the capacitive impedance between the terminal a and the terminal B is changed, and the program-controlled capacitive impedance is realized.
In the prior art scheme in fig. 1, the PMOS element may be replaced by an NMOS (N-type insulated gate field effect transistor, hereinafter referred to as NMOS) element to achieve the same effect of adjusting the capacitive impedance.
Since the channel resistance (hereinafter referred to as on-resistance) of PMOS or NMOS in the on state is associated with the parasitic capacitance between the terminals, if the on-resistance is reduced, a larger PMOS or NMOS is required, and the parasitic capacitance between the terminals is also increased; in order to make the parasitic capacitance between the respective terminals small, the size of PMOS or NMOS needs to be reduced, and on-resistance increases.
Both the on-resistance of the PMOS or NMOS and the parasitic capacitance of the respective terminals reduce the impedance and bandwidth performance of the capacitive impedance element in high frequency applications, e.g. the capacitive impedance of the capacitive element is negligible when the frequency is very high, where the on-resistance impedance dominates the total impedance, and it is often desirable that the series resistance be smaller the better in the circuit. The existing scheme has difficulty in high frequency application because on-resistance of PMOS and NMOS and parasitic capacitance between respective terminals are contradictory to each other.
Disclosure of Invention
In order to reduce the influence of on-resistance and parasitic capacitance of a switching element in a programmable capacitive impedance circuit in the prior art and improve the high-frequency performance of the programmable capacitive impedance circuit, the invention provides a high-frequency programmable capacitive impedance circuit and a measuring device.
In one aspect, the present invention provides a high frequency programmable capacitive impedance circuit comprising at least one high frequency capacitive impedance unit, the high frequency capacitive impedance unit comprising: the signal input end of the program-controlled amplifier is used as the signal input end of the high-frequency capacitive impedance unit, and the output end of the capacitor is used as the signal output end of the high-frequency capacitive impedance unit.
In an embodiment, when the high-frequency capacitive impedance unit is plural, the high-frequency capacitive impedance units are connected in parallel.
In an embodiment, the programmable amplifier is a common collector follower amplifier, the common collector follower amplifier comprising: a first triode and a first controllable current source;
the first triode is used for amplifying or isolating an input signal;
The first controllable current source comprises a current output end and a control end, wherein the current output end is connected with the emitting electrode of the first triode, and the first controllable current source is used for controlling the bias state of the triode according to the signal of the control end.
In an embodiment, the first controllable current source is a second triode, a base electrode of the second triode is used as a control end, an emitter electrode of the second triode is connected with a common ground end, and a collector electrode of the second triode is used as a current output end and is connected with the emitter electrode of the first triode.
In an embodiment, the first controllable current source further includes a resistor, and an emitter of the second triode is connected to the ground common terminal through the resistor.
In an embodiment, the first controllable current source is a first field effect transistor, a gate of the first field effect transistor is used as a control end, a source of the first field effect transistor is connected to a ground common end, and a drain of the first field effect transistor is used as a current output end and is connected to an emitter of the first triode.
In an embodiment, the first controllable current source further includes a resistor, and a source of the first field effect transistor is connected to the ground common terminal through the resistor.
In an embodiment, the first controllable current source is a voltage controlled current source.
In an embodiment, the first controllable current source includes a constant current source and an electronic switch, the constant current source is connected in series with the electronic switch, and the control end is used for controlling the electronic switch to be turned on or off so as to control the current output by the current output end to be a non-zero value or 0.
In an embodiment, the programmable amplifier is a common drain follower amplifier, the common drain follower amplifier comprising: a second field effect transistor and a second controllable current source;
the second field effect transistor is used for amplifying or isolating an input signal;
the second controllable current source comprises a current output end and a control end, wherein the current output end is connected with the source electrode of the field effect transistor, and the second controllable current source is used for controlling the bias state of the second field effect transistor according to the signal of the control end.
In an embodiment, the second controllable current source is a third triode, a base electrode of the third triode is used as a control end, an emitter electrode of the third triode is connected with a common ground end, and a collector electrode of the third triode is used as a current output end and is connected with a source electrode of the second field effect transistor.
In an embodiment, the second controllable current source further includes a resistor, and an emitter of the third triode is connected to the ground common terminal through the resistor.
In an embodiment, the second controllable current source is a third field effect transistor, a gate of the third field effect transistor is used as a control end, a source of the third field effect transistor is connected to a ground common end, and a drain of the third field effect transistor is used as a current output end and is connected to a source of the second field effect transistor.
In an embodiment, the second controllable current source further includes a resistor, and a source of the third field effect transistor is connected to the ground common terminal through the resistor.
In an embodiment, the second controllable current source is a voltage controlled current source.
In an embodiment, the second controllable current source includes a constant current source and an electronic switch, the constant current source is connected in series with the electronic switch, and the control end is used for controlling the electronic switch to be turned on or off so as to control the current output by the current output end to be a non-zero value or 0.
In an embodiment, the second field effect transistor is an N-type MOS transistor, a P-type MOS transistor, an N-type JFET transistor, or a P-type JFET transistor.
In an embodiment, the program-controlled amplifier is a first operational amplifier, the non-inverting input end of the first operational amplifier is a signal input end of the high-frequency capacitive impedance unit, a feedback circuit is connected between the inverting input end of the first operational amplifier and the output end of the first operational amplifier, the output end of the first operational amplifier is connected with the capacitor, and the enabling end of the first operational amplifier is a control end for controlling the working state of the first operational amplifier according to a signal applied to the control end of the first operational amplifier.
In another aspect, the present invention provides a measurement device, including: a second operational amplifier, an AD converter and the high-frequency programmable capacitive impedance circuit;
the high-frequency programmable capacitive impedance circuit is connected in parallel with the first resistor and then connected between the inverting input end and the output end of the second operational amplifier, wherein the input end of the high-frequency programmable capacitive impedance circuit is connected with the output end of the second operational amplifier, and the output end of the high-frequency programmable capacitive impedance circuit is connected with the inverting input end of the second operational amplifier;
the output end of the second operational amplifier is connected with the input end of the AD converter, the non-inverting input end of the second operational amplifier is connected with the common ground end, and the inverting input end of the second operational amplifier is connected with the signal input end of the measuring device through an impedance network.
In one embodiment, the measuring device further comprises a second resistor, and the high-frequency programmable capacitive impedance circuit is connected in series with the second resistor and then connected in parallel with the first resistor.
The invention can reduce the influence of the on-resistance and parasitic capacitance of the switching element of the high-frequency program-controlled capacitive impedance circuit in the prior art, and improve the high-frequency performance of the high-frequency program-controlled capacitive impedance circuit.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a conventional high frequency programmable capacitive impedance circuit;
fig. 2 is a schematic structural diagram of a single high-frequency capacitive impedance unit according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a high frequency programmable capacitive impedance circuit including a common collector follower amplifier according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a high frequency programmable capacitive impedance circuit including a common collector follower amplifier according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a third embodiment of a high frequency programmable capacitive impedance circuit including a common collector follower amplifier;
FIG. 6 is a schematic diagram of a high frequency programmable capacitive impedance circuit including a common collector follower amplifier according to a fourth embodiment of the present invention;
FIGS. 7A-7F illustrate a first form of a controllable current source formed by a triode or field effect transistor in accordance with embodiments of the present invention;
FIGS. 8A-8F illustrate a second form of controllable current source comprising transistors or field effect transistors and resistors in accordance with embodiments of the present invention;
FIG. 9 is a schematic diagram of a high frequency programmable capacitive impedance circuit including a common collector follower amplifier according to a fifth embodiment of the present invention;
FIG. 10 is a schematic diagram of a controllable current source composed of a constant current source and an electronic switch according to an embodiment of the present invention;
FIGS. 11A-11E are schematic diagrams of a controllable current source composed of a transistor and an electronic switch according to an embodiment of the present invention;
FIG. 12 is a schematic diagram of a controllable current source composed of an operational amplifier, a transistor and a resistor according to an embodiment of the present invention;
FIG. 13 is a schematic diagram of a high frequency programmable capacitive impedance circuit including a common drain follower amplifier according to an embodiment of the present invention;
FIG. 14 is a schematic diagram of a high frequency programmable capacitive impedance circuit including a common drain follower amplifier according to an embodiment of the present invention; FIG. 15 is a schematic diagram of a third embodiment of a high frequency programmable capacitive impedance circuit including a common drain follower amplifier;
FIG. 16 is a schematic diagram of a high frequency programmable capacitive impedance circuit with a four-program controlled amplifier as a common drain follower amplifier according to an embodiment of the present invention;
FIG. 17 is a schematic diagram of a high frequency programmable capacitive impedance circuit embodying a routine controlled amplifier as an operational amplifier in accordance with the present invention;
FIG. 18 is a schematic diagram of a measuring apparatus according to an embodiment of the present invention;
fig. 19 is a schematic view of another structure of a measuring device according to an embodiment of the invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention provides a high-frequency programmable capacitive impedance circuit, which comprises at least one high-frequency capacitive impedance unit, wherein the high-frequency capacitive impedance unit further comprises a programmable amplifier and a capacitor, and the programmable amplifier is connected in series with the capacitor, wherein the signal input end of the programmable amplifier is used as the signal input end of the high-frequency capacitive impedance unit, and the output end of the capacitor is used as the signal output end of the high-frequency capacitive impedance unit.
By utilizing the invention, the influence of the on-resistance and parasitic capacitance of the switching element of the program-controlled capacitive impedance circuit in the prior art can be reduced, and the high-frequency performance of the program-controlled capacitive impedance circuit is improved.
The basic structure of the high-frequency capacitive impedance unit is shown in fig. 2, and the high-frequency capacitive impedance unit is composed of an input end a, a programmable amplifier Amp, a capacitive impedance element C and an output end B which are sequentially connected in series. The programmable amplifier also has a control terminal E to which changing the signal state can control the gain of the programmable amplifier to 0 or some non-zero value.
When the high-frequency program-controlled capacitive impedance circuit comprises a plurality of high-frequency capacitive impedance units, the high-frequency capacitive impedance units are connected in parallel, namely the signal input ends of the high-frequency capacitive impedance units are connected together, and the signal output ends of the high-frequency capacitive impedance units are connected together. In the embodiment of the present invention, the high-frequency capacitive impedance circuit is only described by taking two high-frequency capacitive impedance units as an example, but in practical application, the high-frequency capacitive impedance circuit may only include one high-frequency capacitive impedance unit, or may also include a plurality of high-frequency capacitive impedance units.
The programmable amplifier may be a programmable follower amplifier. The programmable follower amplifier generally comprises the following types: a programmable follower amplifier composed of operational amplifier and a programmable follower amplifier composed of transistor. The program-controlled follower amplifier composed of transistors can also be classified into a common collector follower amplifier and a common drain follower amplifier according to the type of transistors.
Typically, the common collector follower amplifier includes a triode and a controllable current source. The triode is also called a bipolar transistor, and can be divided into PNP and NPN according to different polarities, and is used for amplifying or isolating an input signal. The controllable current source is used for controlling the bias state of the triode to bias the triode into an amplifying state or a cut-off state. Normally, the base electrode of the triode is used as a signal input end, and the collector electrode of the triode is connected with the common end of the power supply; the controllable current source comprises a current output end and a control end, wherein the current output end is connected with the emitting electrode of the triode, and the controllable current source is used for controlling the bias state of the triode according to the signal state applied to the control end, namely controlling the triode to be turned on or turned off. When the controllable current source outputs non-zero current (the current is between tens microamperes and tens milliamperes in general), the triode is in an amplifying state, and the gain of the common collector follower amplifier is close to 1 (0.99 in general); when the output current of the controllable current source is 0, the triode is in a cut-off state, and the gain of the controllable amplifier is close to 0, namely the output and the input of the common collector follower amplifier are isolated from each other.
The controllable current sources in the common collector follower amplifier and the common drain follower amplifier may be controllable current sources of voltage controlled current sources.
Fig. 3 is a first embodiment of a high frequency programmable capacitive impedance circuit including a common collector follower amplifier. One of the common collector follower amplifiers shown in fig. 3 is composed of an NPN transistor Q1 (hereinafter referred to as transistor Q1) and a controllable current source G1 (hereinafter referred to as current source G1), the collector of the transistor Q1 is connected to a common power source VCC, the emitter thereof is connected to a current output terminal of the current source G1, the signal input terminal of the common collector follower amplifier is the base of the transistor Q1, the signal output terminal is the emitter of the transistor Q1, and the control terminal is a terminal E1 connected to a "+" control terminal of the current source G1. The output end of the common collector follower amplifier is connected in series with a capacitor C1 to form a first high-frequency capacitive impedance unit.
As above, the transistor Q2 and the current source G2 constitute a second common collector follower amplifier, and the second common collector follower amplifier and the capacitor C2 constitute a second high-frequency capacitive impedance unit. A plurality of the high-frequency capacitive impedance units are connected in parallel, and the overall capacitive impedance can be adjusted by controlling the on-off of the bias current of each high-frequency capacitive impedance unit, so that a high-frequency program-controlled capacitive impedance circuit is realized. The invention is described by taking the parallel connection of two identical high-frequency capacitive impedance units as an example, and the number of the high-frequency capacitive impedance units and the composition form of the high-frequency capacitive impedance units can be flexibly changed according to actual requirements in the specific implementation, and the invention is not limited to the above.
The two high-frequency capacitive impedance units are connected in parallel to form a high-frequency program-controlled capacitive impedance circuit, and the input end of the circuit is a terminal A, and the output end of the circuit is a terminal B.
When the control signal applied to the control terminal E1 is at a high level, the current output terminal of the current source G1 outputs current to provide bias current for the triode Q1, the triode Q1 is conducted, and the first common collector follower amplifier forms an amplifier with gain close to 1, which is equivalent to a conducted switch; when the control signal applied to the control terminal E1 is low, the current source G1 does not output current, the transistor Q1 is turned off due to no bias current, and the gain of the first common collector follower amplifier is close to 0, which corresponds to an off switch. Similarly, when the control signal applied to the control terminal E2 is at a high level, the second common collector follower amplifier corresponds to a conductive switch; the second common collector follower amplifier corresponds to an open switch when the control signal applied to control terminal E2 is low.
When the control signal applied to the control terminal E1 is low and the control signal applied to the control terminal E2 is also low, the signal at the terminal a cannot be transmitted to the capacitor C1 and the capacitor C2, and the capacitive impedance from the terminal a to the terminal B is 0.
When the control signal applied to the control terminal E1 is at a high level and the control signal applied to the control terminal E2 is at a low level, the signal at the terminal a is transmitted to the capacitor C1 in a ratio close to 1:1 but cannot be transmitted to the capacitor C2, and the capacitive impedance from the terminal a to the terminal B is close to the capacitive impedance of the capacitor C1.
When the control signal applied to the control terminal E1 is at a low level and the control signal applied to the control terminal E2 is at a high level, the signal at the terminal a is transmitted to the capacitor C2 in a ratio close to 1:1 and cannot be transmitted to the capacitor C1, and the capacitive impedance of the terminal a to the terminal B is close to the capacitive impedance of the capacitor C2.
When the control signal applied to the control terminal E1 is at a high level and the control signal applied to the control terminal E2 is also at a high level, the signal at the terminal a is transmitted to the capacitor C1 and the capacitor C2 in a ratio close to 1:1, and the capacitive impedance of the terminal a to the terminal B is close to the sum of the capacitive impedances of C1 and C2.
As described above, by changing the state of the control signals applied to the control terminals E1 and E2, the capacitive impedance between the terminals a to B can be changed, thereby realizing the function of programming the capacitive impedance.
Fig. 4 is a schematic diagram of a further embodiment of a high frequency programmable capacitive impedance circuit including a common collector follower amplifier, which differs from the high frequency programmable capacitive impedance circuit of fig. 3 in that both common collector follower amplifiers of fig. 4 are composed of PNP transistors and controllable current sources. One of the common collector follower amplifiers is composed of a PNP triode Q3 (hereinafter referred to as triode Q3) and a controllable current source G1 (hereinafter referred to as current source G1), the collector of the triode Q3 is connected with a power supply common end VCC, the emitter of the triode Q3 is connected with the current output end of the current source G1, the signal input end of the common collector follower amplifier is the base electrode of the triode Q3, the signal output end is the emitter of the triode Q3, and the control end is a terminal E1 connected with the "+" control end of the current source G1. The output end of the common collector follower amplifier is connected in series with a capacitor C1 to form a first high-frequency capacitive impedance unit.
Similarly, the triode Q4 and the current source G2 form a second common collector follower amplifier, and the second common collector follower amplifier and the capacitor C2 form a second high-frequency capacitive impedance unit. The two high-frequency capacitive impedance units are connected in parallel to form a high-frequency program-controlled capacitive impedance circuit, and the input end of the circuit is a terminal A, and the output end of the circuit is a terminal B.
When the control signal applied to the control terminal E1 is at a high level, the current output terminal of the current source G1 outputs a current, the transistor Q3 is turned off, the first common collector follower amplifier is turned off, and the gain is close to 0, which corresponds to an off switch. Similarly, when the control signal applied to the control terminal E2 is low, the gain of the second common collector follower amplifier is close to 1, which corresponds to a conductive switch. When the control signal applied to the control terminal E1 is at a low level, the current source G1 does not output current, and the first common collector follower amplifier corresponds to a conductive switch; similarly, when the control signal applied to the control terminal E2 is high, the second common collector follower amplifier corresponds to an open switch.
Similar to the operation of the circuit of fig. 3, in fig. 4, the programmable capacitive impedance function is also achieved by changing the capacitive impedance between terminals a to B by changing the state of the control signals applied to control terminals E1 and E2.
As shown in fig. 4, when the control signal applied to the control terminal E1 is at a high level and the control signal applied to the control terminal E2 is also at a high level, the signal at the terminal a cannot be transmitted to the capacitor C1 and the capacitor C2, and the capacitive impedance from the terminal a to the terminal B is 0.
When the control signal applied to the control terminal E1 is at a low level and the control signal applied to the control terminal E2 is at a high level, the signal at the terminal a is transmitted to the capacitor C1 in a ratio close to 1:1 but cannot be transmitted to the capacitor C2, and the capacitive impedance from the terminal a to the terminal B is close to the capacitive impedance of the capacitor C1.
When the control signal applied to the control terminal E1 is at a high level and the control signal applied to the control terminal E2 is at a low level, the signal at the terminal a is transmitted to the capacitor C2 in a ratio close to 1:1 and cannot be transmitted to the capacitor C1, and the capacitive impedance from the terminal a to the terminal B is close to the capacitive impedance of the capacitor C1.
When the control signal applied to the control terminal E1 is at a low level and the control signal applied to the control terminal E2 is at a low level, the signal at the terminal a is transmitted to the capacitor C1 and the capacitor C2 in a ratio of approximately 1:1, and the capacitive impedance of the terminal a to the terminal B is approximately equal to the sum of the capacitive impedances of C1 and C2.
Both controllable current sources G1, G2 in fig. 3, 4 may be implemented as transistors, as shown in fig. 7A. The invention provides a high-frequency program-controlled capacitive impedance circuit with a controllable current source realized by an NPN triode on the basis of fig. 3, as shown in fig. 5. In fig. 5, transistor Q5 forms a first controllable current source circuit and forms a first common collector follower amplifier with transistor Q1. The base electrode of the triode Q5 is connected with the control end E1 to serve as a control end, the emitter electrode of the triode Q5 is connected with the common ground end, the collector electrode of the triode Q1 serves as a current output end and is connected with the emitter electrode of the triode Q1, and the triodes Q5 and Q1 and the capacitor C1 form a first high-frequency capacitive impedance unit. Similarly, transistor Q6 constitutes a second controllable current source and forms a second common collector follower amplifier with transistor Q2. The base electrode of the triode Q6 is connected with the control end E2 to serve as a control end, the emitter electrode of the triode Q6 is connected with the grounded common end, the collector electrode of the triode Q2 serves as a current output end, and the triodes Q6 and Q2 and the capacitor C2 form a second high-frequency capacitive impedance unit. The two high-frequency capacitive impedance units are connected in parallel to form a high-frequency capacitive impedance circuit, the input end of the circuit is a terminal A, and the output end of the circuit is a terminal B.
In fig. 5, when the control signal applied to the control terminal E1 is at a high level, the collector of the transistor Q5 outputs a current to provide a bias current to the transistor Q1, and the first common collector follower amplifier forms an amplifier with a gain close to 1, which is equivalent to a conducting switch; when the control signal applied to the control terminal E1 is low, the collector of the transistor Q5 does not output current, the transistor Q1 is turned off due to no bias current, and the gain of the first common collector follower amplifier is close to 0, which corresponds to an open switch. Similarly, when the control signal applied to the control terminal E2 is at a high level, the second common collector follower amplifier corresponds to a conductive switch; the second common collector follower amplifier corresponds to an open switch when the control signal applied to control terminal E2 is low. Similar to the control principle of the high frequency programmable capacitive impedance circuit shown in fig. 3, the capacitive impedance between terminals a to B in fig. 5 can be changed by changing the control signals applied to the control terminals E1 and E2, thereby realizing the function of programmable capacitive impedance.
The controllable current source formed by the triode can also comprise a resistor, the emitter of the triode is connected with the common ground terminal through the resistor, as shown in fig. 8A, and fig. 6 shows an embodiment of the controllable current source formed by the NPN triode and the resistor. In fig. 6, a transistor Q5 and a resistor R1 are connected in series to form a first controllable current source circuit, and a transistor Q6 and a resistor R2 form a second controllable current source. The performance of the controllable current source can be improved by adding the resistor into the controllable current source, so that the controllable current source is more similar to an ideal controllable current source.
In fig. 5 and fig. 6, only an embodiment in which the transistor Q5 forming the controllable current source is an NPN transistor is shown, and in the specific implementation, the NPN transistor Q5 in the controllable current source may be replaced by a PNP transistor, as shown in fig. 7B and fig. 8B, respectively, which is not limited by the present invention.
In an embodiment, the controllable current source in the common-collector follower amplifier of the high-frequency programmable capacitive impedance circuit shown in fig. 5 may also be a field effect transistor, as shown in fig. 7C to 7F, and fig. 9 shows an embodiment in which the controllable current source in the common-collector follower amplifier is composed of an N-type MOS transistor. In fig. 9, a first controllable current source is formed by an N-type MOS transistor M1 (hereinafter referred to as MOS transistor M1), and a first common collector follower amplifier is formed together with a transistor Q1. The gate (G) of the MOS transistor M1 is connected to the control terminal E1 as a control terminal, the source (S) thereof is connected to the common ground terminal, the drain (D) thereof is connected to the emitter of the transistor Q1 as a current output terminal, and the transistor Q1, the MOS transistor M1 and the capacitor C1 form a first high-frequency capacitive impedance unit. Similarly, an N-type MOS transistor M2 (hereinafter referred to as MOS transistor M2) forms a second controllable current source, and forms a second common collector follower amplifier together with the transistor Q2. The grid electrode (G) of the MOS tube M2 is connected with the control end E2 to serve as a control end, the source electrode (S) of the MOS tube M2 is connected with the common ground end, the drain electrode (D) of the MOS tube M2 serves as a current output end and is connected with the emitting electrode of the triode Q2, and the triode Q2, the MOS tube M2 and the capacitor C2 form a second high-frequency capacitive impedance unit. The two high-frequency capacitive impedance units are connected in parallel to form a high-frequency capacitive impedance circuit, the input end of the circuit is a terminal A, and the output end of the circuit is a terminal B.
In fig. 9, when the control signal applied to the control terminal E1 is at a high level, the drain of the MOS transistor M1 outputs a current to provide a bias current to the transistor Q1, and the first common collector follower amplifier forms an amplifier with a gain close to 1, which is equivalent to a conducting switch; when the control signal applied to the control terminal E1 is at a low level, the drain of the MOS transistor M1 does not output current, the transistor Q1 is turned off due to no bias current, and the gain of the first common collector follower amplifier is close to 0, which corresponds to an off switch. Similarly, when the control signal applied to the control terminal E2 is at a high level, the second common collector follower amplifier corresponds to a conductive switch; the second common collector follower amplifier corresponds to an open switch when the control signal applied to control terminal E2 is low. Similar to the control principle of the high-frequency programmable capacitive impedance circuit shown in fig. 3, the capacitive impedance between the terminals a to B in fig. 9 can be changed by changing the control signals applied to the control terminals E1 and E2 of the high-frequency programmable capacitive impedance circuit in fig. 9, thereby realizing the function of programmable capacitive impedance.
Similar to the form of one of the controllable current sources shown in fig. 6, which is a "triode q5+resistor R1", the controllable current source composed of MOS transistors may further include a resistor through which the source of the MOS transistor is connected to the ground common, as shown in fig. 8C and 8D. When the source electrode of the MOS tube is connected with the grounded common end through a resistor, the current output end of the controllable current source is the drain electrode of the MOS tube, and the control end is a terminal E1 connected with the grid electrode of the MOS tube. The resistor herein can act to reduce the gain of the voltage-to-current conversion (also known as transconductance) and to increase the stability of the circuit by providing some negative feedback. The controllable current source can also be formed by serially connecting JFET tubes and resistors, as shown in fig. 8E and 8F, and the working principle of the controllable current source is similar to that of a controllable current source in a form of a MOS tube and a resistor.
The controllable current source in the common collector follower amplifier may be implemented in the forms shown in fig. 10, 11A to 11E, and 12, in addition to the above forms, and the present invention is not limited thereto.
In fig. 10, the controllable current source is composed of a constant current source I1 and an electronic switch S, wherein the constant current source I1, the electronic switch S and the current output terminal Io are sequentially connected in series, and the control terminal E1 controls the current at the current output terminal Io to be equal to the current output by the constant current source I1 or 0 by controlling the on or off of the electronic switch S.
The controllable current source shown in fig. 11A is composed of a triode Q7 and a MOS transistor M3, wherein the collector of the triode Q7 is used as the current output end of the controllable current source, and the base of the triode Q7 is used as the control end of the controllable current source. The controllable current source shown in fig. 11B is composed of two JFET transistors, the drain (i.e., terminal 3) of JFET transistor J1 being the current output terminal of the controllable current source, and the gate (i.e., terminal 2) of JFET transistor J1 being the control terminal of the controllable current source. The controllable current source shown in fig. 11C is composed of two transistors, the collector of the transistor Q8 is used as the current output terminal of the controllable current source, and the base of the transistor Q8 is used as the control terminal of the controllable current source. The controllable current source shown in fig. 11D is composed of two MOS transistors, the drain electrode of the MOS transistor M4 is used as the current output end of the controllable current source, and the gate electrode of the MOS transistor M4 is used as the control end of the controllable current source. The controllable current source shown in fig. 11E is composed of two JFET tubes and a resistor R3, wherein the JFET tube J4 and the resistor R3 form a self-biased constant current source, the drain (i.e., terminal 3) of the JFET tube J3 is used as the current output terminal of the controllable current source, and the gate (i.e., terminal 2) of the JFET tube J3 is used as the control terminal of the controllable current source.
In fig. 11A to 11D, vb is a bias voltage such that the transistors M3, J2, Q9, and M5 output currents of a specific magnitude, respectively, as constant current sources. In fig. 11A to 11E, the voltage applied to the control terminal E1 is used to control the on and off of the transistors Q7, J1, Q8, M4, and J3, respectively, so as to control the presence or absence of current at the current output terminal Io.
The controllable current source shown in fig. 12 is composed of an operational amplifier, a transistor and a resistor. In fig. 12, the output end (i.e., terminal 6) of the operational amplifier U1 is connected to the base of the transistor Q10, the inverting input end (i.e., terminal 5) thereof is connected to the emitter of the transistor Q10, and then is connected to the ground common end through the resistor R4, the non-inverting input end (i.e., terminal 4) of the operational amplifier U1 serves as the control end E1 of the controllable current source, and the collector of the transistor Q10 serves as the current output end of the controllable current source.
The invention reduces the series resistance and parasitic capacitance of the programmable capacitive impedance circuit by using the bias controllable common collector amplifier as the switch, so that the programmable capacitive impedance circuit is more suitable for high-frequency application.
Because the input end of the high-frequency program-controlled capacitive impedance circuit is the input end of the common collector amplifier, the size of the input capacitance of the high-frequency program-controlled capacitive impedance circuit is irrelevant to the size of the capacitance elements (C1 and C2) contained in the circuit due to the impedance transformation function of the common collector amplifier, and the capacitance value of the high-frequency program-controlled capacitive impedance circuit is much smaller than that of the capacitance elements, so that the capacitive load of the driving single-way of the upper stage can be reduced, and the high-frequency program-controlled capacitive impedance circuit is more suitable for high-frequency application.
The output impedance of the common collector amplifier is mainly influenced by bias current, and the larger the bias current is, the lower the output impedance is; the smaller the bias current, the higher the output impedance. The parasitic capacitance of the common collector amplifier is mainly the base input capacitance of the triode forming the common collector amplifier, and is mainly influenced by the size of the triode, and the larger the size is; the larger the capacitance, the smaller the size and the smaller the capacitance. The parasitic capacitance and the output impedance of the common collector amplifier are very small in association degree and can be adjusted respectively without obvious contradiction, so that the parasitic capacitance and the output impedance of the three connecting pipes can be very small, and the parasitic capacitance and the parasitic resistance of the high-frequency program-controlled capacitive impedance circuit formed by the three connecting pipes can be very small, thereby improving the high-frequency performance of the high-frequency program-controlled capacitive impedance circuit.
Typically, the common drain follower amplifier includes a field effect transistor and a controllable current source. The field effect transistor comprises a MOS transistor, a JFET transistor and the like, and in the common drain follower amplifier, the field effect transistor is used for amplifying or isolating an input signal, and the controllable current source is used for controlling the bias state of the field effect transistor so as to bias the field effect transistor into an amplifying state or a cut-off state. Typically, the gate of the field effect transistor here is the signal input, the drain of which is connected to the power supply common; the controllable current source comprises a current output end and a control end, wherein the current output end is connected with the source electrode of the field effect transistor, and the controllable current source is used for controlling the bias state of the field effect transistor according to the signal of the control end, namely controlling the on or off of the field effect transistor. When the current output by the controllable current source is non-zero (the current is generally between tens microamps and tens milliamperes), the field effect transistor is in an amplifying state, and the gain of the common drain follower amplifier is close to 1 (generally 0.99); when the current output by the controllable current source is 0, the field effect transistor is in an off state, and the gain of the common drain follower amplifier is close to 0, namely the output and the input of the common drain follower amplifier are isolated from each other.
Fig. 13 is a high frequency programmable capacitive impedance circuit including a common drain follower amplifier. One of the common drain follower amplifiers shown in fig. 13 is composed of an N-type MOS transistor M5 (hereinafter referred to as MOS transistor M5) and a controllable current source G1, the drain of the MOS transistor M5 is connected to a common power source VCC, the source thereof is connected to a current output terminal of the current source G1, the signal input terminal of the common drain follower amplifier is a gate of the MOS transistor M5, the signal output terminal is a source of the MOS transistor M5, and the control terminal is a terminal E1 connected to a "+" control terminal of the current source G1. The output end of the common drain follower amplifier is connected in series with a capacitor C1 to form a first high-frequency capacitive impedance unit.
The MOS tube M6 and the current source G2 form a second common drain electrode following amplifier, and the second common drain electrode following amplifier and the capacitor C2 form a second high-frequency capacitive impedance unit. The two high-frequency capacitive impedance units are connected in parallel to form a high-frequency program-controlled capacitive impedance circuit, and the input end of the circuit is a terminal A, and the output end of the circuit is a terminal B.
In fig. 13, when the control signal applied to the control terminal E1 is at a high level, the current output terminal of the current source G1 outputs a current, the MOS transistor M5 is turned off, the first common drain follower amplifier is turned off, and the gain is close to 0, which corresponds to an off switch. Similarly, when the control signal applied to the control terminal E2 is low, the gain of the second common drain follower amplifier is close to 1, which corresponds to a conductive switch. When the control signal applied to the control terminal E1 is at a low level, the current source G1 does not output current, and the first common drain follower amplifier corresponds to a conductive switch; similarly, when the control signal applied to the control terminal E2 is high, the second common drain follower amplifier corresponds to an open switch.
Similar to the circuit of fig. 4, the circuit of fig. 13 also achieves a programmable capacitive impedance function by varying the capacitive impedance between terminals a through B by varying the control signals applied to control terminals E1 and E2.
As shown in fig. 13, when the control signal applied to the control terminal E1 is at a high level and the control signal applied to the control terminal E2 is also at a high level, the signal at the terminal a cannot be transmitted to the capacitor C1 and the capacitor C2, and the capacitive impedance from the terminal a to the terminal B is 0.
When the control signal applied to the control terminal E1 is at a low level and the control signal applied to the control terminal E2 is at a high level, the signal at the terminal a is transmitted to the capacitor C1 in a ratio close to 1:1 but cannot be transmitted to the capacitor C2, and the capacitive impedance from the terminal a to the terminal B is close to the capacitive impedance of the capacitor C1.
When the control signal applied to the control terminal E1 is at a high level and the control signal applied to the control terminal E2 is at a low level, the signal at the terminal a is transmitted to the capacitor C2 in a ratio close to 1:1 and cannot be transmitted to the capacitor C1, and the capacitive impedance from the terminal a to the terminal B is close to the capacitive impedance of the capacitor C2.
When the control signal applied to the control terminal E1 is low and the control signal applied to the control terminal E2 is also low, the signal at the terminal a is transmitted to the capacitor C1 and the capacitor C2 in a ratio close to 1:1, and the capacitive impedance of the terminal a to the terminal B is close to the sum of the capacitive reactance of the capacitor C1 and the capacitive reactance of the capacitor C2.
Correspondingly, the common drain follower amplifier in fig. 13 may also be composed of P-type MOS transistors and a controllable current source, that is, the MOS transistors M5 and M6 in fig. 13 are replaced by P-type MOS transistors M7 and M8, and the schematic diagram is shown in fig. 14, and the working principle of the high-frequency program-controlled capacitive impedance circuit in fig. 14 is similar to that of the high-frequency program-controlled capacitive impedance circuit in fig. 13, and is not repeated here.
Fig. 15 is a schematic diagram of a high-frequency programmable capacitive impedance circuit including a common drain follower amplifier according to another embodiment of the present invention, which is different from the high-frequency programmable capacitive impedance circuit shown in fig. 13 in that the first common drain follower amplifier in fig. 15 is composed of an N-type JFET J5 (hereinafter referred to as JFET) and a controllable current source G1, the drain (i.e., terminal 1) of the JFET J5 is connected to the power supply common terminal VCC, and the source (i.e., terminal 2) thereof is connected to the current output terminal of the current source G1. The signal input end of the common drain follower amplifier is the grid electrode (namely the terminal 2) of the JFET tube J5, the signal output end is the source electrode of the JFET tube J5, and the control end is the terminal E1 connected with the "+" control end of the current source G1. The output end of the common drain follower amplifier is connected in series with a capacitor C1 to form a first high-frequency capacitive impedance unit.
As above, JFET tube J6 and current source G2 constitute a second common drain follower amplifier, and the second common drain follower amplifier and capacitor C2 constitute a second high-frequency capacitive impedance unit. The two high-frequency capacitive impedance units are connected in parallel to form a high-frequency program-controlled capacitive impedance circuit, and the input end of the circuit is a terminal A, and the output end of the circuit is a terminal B.
When the control signal applied to the control end E1 is at a high level, the current output end of the current source G1 outputs current to provide bias current for the JFET tube J5, and the first common drain follower amplifier forms an amplifier with gain close to 1, which is equivalent to a conducting switch; when the control signal applied to the control terminal E1 is low, the current source G1 does not output current, the JFET J5 is turned off due to no bias current, and the gain of the first common drain follower amplifier is close to 0, which corresponds to an open switch. Similarly, when the control signal applied to the control terminal E2 is at a high level, the second common drain follower amplifier corresponds to a conductive switch; the second common drain follower amplifier corresponds to an open switch when the control signal applied to control terminal E2 is low. By varying the control signals applied to the control terminals E1 and E2, the capacitive impedance between terminals a to B can be varied, thereby achieving the function of programming the capacitive impedance. The working principle of the high-frequency programmable capacitive impedance circuit shown in fig. 15 is similar to that of the high-frequency programmable capacitive impedance circuit in fig. 3, and will not be described here again.
Fig. 16 is a schematic diagram of a high-frequency programmable capacitive impedance circuit including a common drain follower amplifier according to an embodiment of the present invention, which is different from the schematic diagram of fig. 15 in that one of the common drain follower amplifiers in fig. 16 is composed of a P-type JFET J7 and a controllable current source G1, and the working principle of the schematic diagram of the high-frequency programmable capacitive impedance circuit in fig. 16 is similar to that of the schematic diagram of the high-frequency programmable capacitive impedance circuit in fig. 15, and will not be repeated here.
The implementation form of the high-frequency programmable capacitive impedance circuit provided by the invention when the programmable amplifier is a common drain follower amplifier is not limited to fig. 13 to 16, and similar to the common collector follower amplifier, the controllable current source in the common drain follower amplifier also has various implementation forms, such as the forms of fig. 7A to 7F, fig. 8A to 8F, fig. 10, fig. 11A to 11E, fig. 12, etc., but the above embodiments are only used for illustrating the invention and are not limited thereto.
Fig. 17 is a further embodiment of the high frequency programmable capacitive impedance circuit where the programmable amplifier is an operational amplifier. As shown in fig. 17, when the programmable amplifier in one of the high-frequency capacitive impedance units is composed of an operational amplifier, the non-inverting input terminal (i.e., terminal 4) of the operational amplifier U2 is used as the signal input terminal of the high-frequency capacitive impedance unit, a feedback circuit is connected between the inverting input terminal (terminal 5) and the output terminal (terminal 6), the output terminal of the operational amplifier U2 is connected to a capacitor, and the enabling terminal of the operational amplifier U2 is a control terminal E1 for controlling the operation state of the operational amplifier U2 according to the signal applied to the enabling terminal of the operational amplifier U1.
Similarly, the operational amplifier U3 forms a second programmable amplifier, and the second programmable amplifier and the capacitor C2 form a second high-frequency capacitive impedance unit. The two high-frequency capacitive impedance units are connected in parallel to form a high-frequency program-controlled capacitive impedance circuit, and the input end of the circuit is a terminal A, and the output end of the circuit is a terminal B.
As well known to those skilled in the art, the parallel structure of two high-frequency capacitive impedance units is used in the embodiment of the present invention, a single high-frequency capacitive impedance unit may be used when the adjustment resolution of the high-frequency capacitive impedance unit is small, or three or more high-frequency capacitive impedance units may be used in parallel to achieve a larger adjustment resolution and adjustment range of the capacitive impedance.
The invention also provides a measuring device which comprises the high-frequency program-controlled capacitive impedance circuit in any form, an operational amplifier and an AD converter, and the structural schematic diagram of the measuring device is shown in figure 18. In fig. 18, after the high-frequency capacitive impedance circuit is connected in parallel with the resistor R5, the high-frequency capacitive impedance circuit is connected in parallel between the inverting input terminal (terminal 5) and the output terminal (terminal 6) of the operational amplifier U4, wherein the input terminal of the high-frequency capacitive impedance circuit is connected with the output terminal of the operational amplifier U4, the output terminal of the high-frequency capacitive impedance circuit is connected with the inverting input terminal of the operational amplifier U4, the output terminal of the operational amplifier U4 is connected with the input terminal of the AD converter, the non-inverting input terminal (terminal 4) of the operational amplifier U4 is connected with the ground common terminal, the inverting input terminal thereof is connected with the signal input terminal (terminal in) of the measuring device through an impedance network, and the output terminal (terminal out) of the measuring device is used for outputting digital signals.
In order to adjust the frequency response of the circuit of the measuring device except the AD converter, a resistor R6 is usually connected in the measuring device shown in fig. 18, wherein the high-frequency programmable capacitive impedance circuit is connected in series with the resistor R6, then connected in parallel with the resistor R5, and then connected in parallel between the inverting input terminal and the output terminal of the operational amplifier U4, and the specific connection manner is shown in fig. 19.
The prior art measuring device is essentially the same as the measuring device of the present invention except that the high frequency programmable capacitive impedance circuit uses the scheme shown in fig. 1. The solution shown in fig. 1 has the problems of large parasitic series resistance and large capacitive load for the operational amplifier, so that the measuring device formed by the solution has poor frequency response and poor high-frequency performance. The present invention overcomes these problems and allows for a higher bandwidth measurement device.
Furthermore, prior art schemes use field effect transistors as switches, which can only be implemented by integrated circuit processes with field effect transistors. The invention can be realized by using a bipolar integrated circuit process, can also be realized by using a field effect transistor integrated circuit process, can also be realized by using a bipolar and field effect transistor hybrid integrated circuit process, and has good process flexibility.
The principles and embodiments of the present invention have been described in detail with reference to specific examples, which are provided to facilitate understanding of the method and core ideas of the present invention; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present invention, the present description should not be construed as limiting the present invention in view of the above.
Claims (15)
1. A measurement device, the measurement device comprising: a second operational amplifier, an AD converter and a high-frequency programmable capacitive impedance circuit; the high frequency programmable capacitive impedance circuit includes at least one high frequency capacitive impedance unit including: the signal input end of the programmable amplifier is used as the signal input end of the high-frequency capacitive impedance unit, the output end of the capacitor is used as the signal output end of the high-frequency capacitive impedance unit, and the programmable amplifier comprises a controllable current source which is used for controlling the programmable amplifier;
the high-frequency programmable capacitive impedance circuit is connected in parallel with the first resistor and then connected between the inverting input end and the output end of the second operational amplifier, wherein the input end of the high-frequency programmable capacitive impedance circuit is connected with the output end of the second operational amplifier, and the output end of the high-frequency programmable capacitive impedance circuit is connected with the inverting input end of the second operational amplifier;
The output end of the second operational amplifier is connected with the input end of the AD converter, the non-inverting input end of the second operational amplifier is connected with the common ground end, and the inverting input end of the second operational amplifier is connected with the signal input end of the measuring device through an impedance network;
the programmable amplifier is a common collector follower amplifier, the common collector follower amplifier comprising: a first triode and a first controllable current source;
the first triode is used for amplifying or isolating an input signal;
the first controllable current source comprises a current output end and a control end, wherein the current output end is connected with the emitter of the first triode, and the first controllable current source is used for controlling the bias state of the first triode according to the signal of the control end;
the first controllable current source comprises a constant current source and an electronic switch, the constant current source is connected with the electronic switch in series, and the control end is used for controlling the electronic switch to be switched on or switched off so as to control the current output by the current output end to be non-zero value or 0;
or alternatively
The program controlled amplifier is a common drain follower amplifier, the common drain follower amplifier comprising: a second field effect transistor and a second controllable current source;
The second field effect transistor is used for amplifying or isolating an input signal;
the second controllable current source comprises a current output end and a control end, wherein the current output end is connected with the source electrode of the field effect transistor, and the second controllable current source is used for controlling the bias state of the second field effect transistor according to the signal of the control end;
or alternatively
The programmable control amplifier is a first operational amplifier, the non-inverting input end of the first operational amplifier is used as the signal input end of the high-frequency capacitive impedance unit, a feedback circuit is connected between the inverting input end of the first operational amplifier and the output end of the first operational amplifier, the output end of the first operational amplifier is connected with the capacitor, and the enabling end of the first operational amplifier is used as a control end and is used for controlling the working state of the first operational amplifier according to the signal added to the control end of the first operational amplifier.
2. The measurement device of claim 1 further comprising a second resistor, wherein the high frequency programmable capacitive impedance circuit is connected in series with the second resistor and then in parallel with the first resistor.
3. The measurement device according to claim 1, wherein when the high-frequency capacitive impedance unit is plural, the high-frequency capacitive impedance units are connected in parallel.
4. The measurement device of claim 1, wherein the first controllable current source is a second triode, a base electrode of the second triode is used as a control end, an emitter electrode of the second triode is connected with a common ground end, and a collector electrode of the second triode is used as a current output end and is connected with an emitter electrode of the first triode.
5. The measurement device of claim 4, wherein the first controllable current source further comprises a third resistor, and wherein the emitter of the second transistor is connected to ground common through the third resistor.
6. The measurement device of claim 1, wherein the first controllable current source is a first field effect transistor, a gate of the first field effect transistor is used as a control terminal, a source of the first field effect transistor is connected to a common ground terminal, and a drain of the first field effect transistor is used as a current output terminal and is connected to an emitter of the first triode.
7. The measurement device of claim 6, wherein the first controllable current source further comprises a fourth resistor, the source of the first field effect transistor being connected to ground common through the fourth resistor.
8. The measurement device of claim 1, wherein the first controllable current source is a voltage-controlled current source.
9. The measurement device of claim 1, wherein the second controllable current source is a third triode, a base electrode of the third triode is used as a control end, an emitter electrode of the third triode is connected to a common ground end, and a collector electrode of the third triode is used as a current output end and is connected to a source electrode of the second field effect transistor.
10. The measurement device of claim 9, wherein the second controllable current source further comprises a fifth resistor, and wherein the emitter of the third transistor is connected to ground common through the fifth resistor.
11. The measurement device of claim 1, wherein the second controllable current source is a third field effect transistor, a gate of the third field effect transistor is used as a control terminal, a source of the third field effect transistor is connected to a common ground terminal, and a drain of the third field effect transistor is used as a current output terminal and is connected to a source of the second field effect transistor.
12. The measurement device of claim 11, wherein the second controllable current source further comprises a sixth resistor, the source of the third field effect transistor being connected to ground common through the sixth resistor.
13. The measurement device of claim 1, wherein the second controllable current source is a voltage-controlled current source.
14. The measuring device of claim 1, wherein the second controllable current source comprises a constant current source and an electronic switch, the constant current source is connected in series with the electronic switch, and the control terminal is configured to control the electronic switch to be turned on or off so as to control the current output by the current output terminal to be a non-zero value or 0.
15. The measurement device of claim 1, wherein the second field effect transistor is an N-type MOS transistor, a P-type MOS transistor, an N-type JFET transistor, or a P-type JFET transistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610054843.9A CN107017876B (en) | 2016-01-27 | 2016-01-27 | High-frequency program-controlled capacitive impedance circuit and measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610054843.9A CN107017876B (en) | 2016-01-27 | 2016-01-27 | High-frequency program-controlled capacitive impedance circuit and measuring device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107017876A CN107017876A (en) | 2017-08-04 |
| CN107017876B true CN107017876B (en) | 2023-09-22 |
Family
ID=59438829
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610054843.9A Active CN107017876B (en) | 2016-01-27 | 2016-01-27 | High-frequency program-controlled capacitive impedance circuit and measuring device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107017876B (en) |
Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4118151A1 (en) * | 1991-06-03 | 1992-12-10 | Philips Patentverwaltung | Non=linear distortion circuit with emitter follower transistor - employs current mirror transistor pair as controllable current source for compensation of input AC component |
| JPH07312095A (en) * | 1994-05-18 | 1995-11-28 | Matsushita Electric Ind Co Ltd | Sample hold circuit |
| CA2206089A1 (en) * | 1997-06-06 | 1998-12-06 | Manvel Zakharian | The method of obtaining the adjustable capacitor |
| CN1610246A (en) * | 2003-10-17 | 2005-04-27 | 松下电器产业株式会社 | Voltage controlled variable capacitor |
| CN101776703A (en) * | 2009-12-25 | 2010-07-14 | 北京普源精电科技有限公司 | Oscilloscope provided with attenuator circuit |
| CN101783684A (en) * | 2009-01-16 | 2010-07-21 | 联发科技股份有限公司 | Pipelined analog-to-digital converter |
| CN101788578A (en) * | 2009-12-25 | 2010-07-28 | 北京普源精电科技有限公司 | Oscilloscope with front end analog circuit |
| CN101949962A (en) * | 2010-05-27 | 2011-01-19 | 东莞市锐源仪器有限公司 | Programmable electronic load |
| JP2011061278A (en) * | 2009-09-07 | 2011-03-24 | Yokogawa Electric Corp | Switched emitter follower circuit |
| CN102740019A (en) * | 2011-03-31 | 2012-10-17 | Nxp股份有限公司 | Receiver comprising amplifier with miller effect feedback |
| CN103344843A (en) * | 2013-07-29 | 2013-10-09 | 国家电网公司 | Measurement system of series compensation capacitor group |
| CN103925474A (en) * | 2014-04-17 | 2014-07-16 | 西北工业大学 | Leakage on-line detection method for weld joint of petroleum and natural gas pipeline |
| CN104207761A (en) * | 2013-06-03 | 2014-12-17 | 飞比特公司 | Heart rate data collection |
-
2016
- 2016-01-27 CN CN201610054843.9A patent/CN107017876B/en active Active
Patent Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4118151A1 (en) * | 1991-06-03 | 1992-12-10 | Philips Patentverwaltung | Non=linear distortion circuit with emitter follower transistor - employs current mirror transistor pair as controllable current source for compensation of input AC component |
| JPH07312095A (en) * | 1994-05-18 | 1995-11-28 | Matsushita Electric Ind Co Ltd | Sample hold circuit |
| CA2206089A1 (en) * | 1997-06-06 | 1998-12-06 | Manvel Zakharian | The method of obtaining the adjustable capacitor |
| US6608405B1 (en) * | 1997-06-06 | 2003-08-19 | Manvel Zakharian | Method of obtaining the adjustable capacitor |
| CN1610246A (en) * | 2003-10-17 | 2005-04-27 | 松下电器产业株式会社 | Voltage controlled variable capacitor |
| CN101783684A (en) * | 2009-01-16 | 2010-07-21 | 联发科技股份有限公司 | Pipelined analog-to-digital converter |
| JP2011061278A (en) * | 2009-09-07 | 2011-03-24 | Yokogawa Electric Corp | Switched emitter follower circuit |
| CN101776703A (en) * | 2009-12-25 | 2010-07-14 | 北京普源精电科技有限公司 | Oscilloscope provided with attenuator circuit |
| CN101788578A (en) * | 2009-12-25 | 2010-07-28 | 北京普源精电科技有限公司 | Oscilloscope with front end analog circuit |
| CN101949962A (en) * | 2010-05-27 | 2011-01-19 | 东莞市锐源仪器有限公司 | Programmable electronic load |
| CN102740019A (en) * | 2011-03-31 | 2012-10-17 | Nxp股份有限公司 | Receiver comprising amplifier with miller effect feedback |
| CN104207761A (en) * | 2013-06-03 | 2014-12-17 | 飞比特公司 | Heart rate data collection |
| CN103344843A (en) * | 2013-07-29 | 2013-10-09 | 国家电网公司 | Measurement system of series compensation capacitor group |
| CN103925474A (en) * | 2014-04-17 | 2014-07-16 | 西北工业大学 | Leakage on-line detection method for weld joint of petroleum and natural gas pipeline |
Also Published As
| Publication number | Publication date |
|---|---|
| CN107017876A (en) | 2017-08-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109347454B (en) | Continuous variable gain amplifier | |
| CN110277966B (en) | Self-calibration circuit and calibration method | |
| CN103326682A (en) | Adjustable operational transconductance amplifier with high linearity | |
| US7242236B2 (en) | Mixer circuit with phase-shifted radio frequency signal | |
| CN110601663A (en) | High speed voltage feedback amplifier with current feedback amplifier characteristics | |
| KR20020035324A (en) | Differential amplifier | |
| CN108429541A (en) | Predistorter for compensating for linearity of amplifier | |
| CN109546981B (en) | Differential input circuit, amplifying circuit, and display device | |
| CN102314189A (en) | Mixed-mode input buffer | |
| CN106774572B (en) | Miller-compensated circuit and electronic circuit | |
| CN210578470U (en) | Comparator with a comparator circuit | |
| GB2321150A (en) | A low noise single ended input/differential output rf amplifier | |
| CN105356852B (en) | A kind of CMOS up-conversions passive frequency mixer | |
| CN107017876B (en) | High-frequency program-controlled capacitive impedance circuit and measuring device | |
| US7119615B2 (en) | Electronic amplifier circuit | |
| CN215956355U (en) | Power amplifying circuit | |
| JPWO2020110252A1 (en) | Active circulator | |
| JP4076858B2 (en) | Fully differential variable gain amplifier and multidimensional amplifier configuration | |
| WO2002051001A3 (en) | A bias circuit for a low voltage differential circuit | |
| CN101453195A (en) | Method for increasing common mode feedback stability by grounding capacitor | |
| CN210380777U (en) | High speed voltage feedback amplifier with current feedback amplifier characteristics | |
| CN101958715B (en) | Audio digital-to-analog converter | |
| CN107896096A (en) | Sampling hold circuit front-end wideband amplifier | |
| JPS6282704A (en) | Amplifier circuit | |
| WO1995035595A2 (en) | Differential amplifier with common-mode rejection for low supply voltages |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB02 | Change of applicant information |
Address after: Kolding road high tech Zone of Suzhou City, Jiangsu Province, No. 8 215163 Applicant after: Puyuan Jingdian Technology Co.,Ltd. Address before: Kolding road high tech Zone of Suzhou City, Jiangsu Province, No. 8 215163 Applicant before: SUZHOU RIGOL PRECISION ELECTRIC TECHNOLOGIES Co.,Ltd. |
|
| CB02 | Change of applicant information | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |