The source of constant current to grounded load
(57) Abstract:Usage: multifunctional measuring instruments (multimeters) when improving ammelrooy their part. The inventive source of constant current in the operational amplifier (op-amp) 6 and four precision resistors 1-4, two of which are connected to the inverting input of the OS, and the other two-to the not inverting input, the trimmer resistor 8 in series with a resistor in the circuit non-inverting input of the OS - the output of the shelter and two kinematically connected to the switch 9, the movable contacts of which are connected with the resistors connected to the not inverting input of the operational amplifier, the stationary contacts of the first switch are connected with the poles of the source of the input voltage, and the fixed contacts of the second switch are connected one with the earth, and the second with the output of the operational amplifier. When checking (setting) device circuit is converted by using the above-mentioned switches in the differential amplifier, trimmer, the output voltage is reduced to zero. 1 Il. The invention relates to the circuitry of electronic devices, namely, integrated electronics, use the power load. Primary area of use in measurement technology - ohmmeters measure resistance DC grounded conclusion of the test resistor.A well-known source of constant current on the basis of an operational amplifier with negative and positive feedbacks  . The principal disadvantages of this device lies in the fact that all five of the resistors included in the combined negative and positive feedback must be precisely aligned, as in the absence of approval of the current through the load resistance will be determined with great accuracy and, in addition, the transition from one value of the reference current to another requires the simultaneous change of the resistance of all five resistors.Known also another source of constant current, containing two operational amplifier and five precision resistors  .The disadvantages of this device are its complexity and the need for precise coordination of all five resistors.The closest in technical essence to the invention is a constant current source, containing operational amplifier, four precision resistor, historiquement source of input voltage through another precision resistor with the output of the operational amplifier. Non-inverting input of the shelter through the third precision resistor connected to the common point of the device ("earth") and through the fourth precision resistor with the output of the shelter. The load is connected between reinvestiruet entrance of the shelter and "earth". The device is operable only when precise coordination of the above precision resistors, forms in load current equal to the ratio of the magnitude of the input voltage to the resistance value of the resistor connected between reinvestiruet input and ground.The disadvantage of the prototype is the need for precise matching of the resistors, because otherwise stable load current is formed with a large error. For example, when using resistors with the deviation from the nominal values of the resistors 1% , stable current will be determined with an error of 4% or more.The disadvantage of the prototype is that even if the condition of the exact matching of the resistors, at higher output currents, the resistor must be small, thus limited output range, i.e., this scheme is used in practice rarely.The technical result, which provides the invention is to increase technasia four precision resistor, the source of the input voltage, operational amplifier, a resistor load, the first output of the first resistor is included with the pole of the input voltage, the other pole is connected to a common point, the other of the resistor connected to the inverting input of the operational amplifier and to the output of the second resistor, the second terminal of which is connected to the output of the operational amplifier, one output of the fourth resistor is connected to the output of the load resistor and not inverting input of the operational amplifier.New in the invention is the fact that it introduced: a trimmer and two kinematically connected to the switch, and the movable contact of the second switch is connected to one output of the third resistor, the other output of which is connected to the output of the load resistor and to the not inverting input of the operational amplifier, the free conclusion of the fourth resistor is connected to the moving contact of the first switch, its one stationary contact connected to a common point, the other pole of the source of the input voltage, to the common point connected to one fixed contact of the second switch, the other stationary contact is connected to the output of the operational amplifier.On chesector 1, the second resistor 2, the third resistor 3, the fourth resistor 4, input 5 conclusions for connection to a voltage source, an operational amplifier 6, the load resistor 7, the trimmer resistor 8, the first switch 9, kinematically associated with the second switch 10.The first resistor 1 single output is connected to the pole of the input voltage, the other pole of which is connected to a common point, the other output of the first resistor connected to the inverting output of the amplifier and one of the conclusions of the second resistor 2, the second terminal of which is connected to the output of the operational amplifier 6, one of the conclusions of the third resistor 3 is connected with a movable contact 11 of the second switch 10, and the other with the output of the trimmer resistor 8; trimmer resistor 8 is connected by its output to the not inverting input of the operational amplifier 6 and the output of the load resistor, this connection point is connected to one of terminals of the resistor 4, the other of the resistor is connected with a movable contact 13 of the first switch 9, the stationary contacts of which includes one 14 to the output of the first resistor 1, the other 12 are connected to a common point and the fixed contact 15 of the second switch 10 is connected to a common point, the other 16 - to Imagna principle of operation for the circuit elements instead of digital used the appropriate letter designation:
5-E, 1-R1, 2-R2, 3-r3,
8 - r3, 4R4, 7-RL, 9-S1THE 10-S2;
R3= r3+ r3< / BR>S1switch (pins 12, 13, 14),
S2switch (pins 11, 15, 16).The device operates as follows. First, make adjustment. Switches S1and S2set in the position "setting" (the movable contacts 11 and 13 are connected with the stationary contacts 14 and 15), and the load is disconnected (R4= = ). The scheme at this moment transformed (converted) into a differential amplifier (2), to the inverting and non-inverting input of which is filed the same voltage that is the Voltage at the output of the operational amplifier (op-amp) is absent, unless the condition:
If this condition is not met, then the output of the operational amplifier there is a voltage offset of the U. for Example, if E = I, R2= R3and when the deviation of R1from R41% , U = 5 mV.Dragging the slider to the resistor r3in one way or another, we have U = 0, i.e., achieve compliance with the conditions above.When the transfer switches S1and S2in position "form stable load current.The principle of the scheme is that as you increase the load resistance is proportional to the increase in positive feedback, which ensures the stable load current. When the load resistance is equal to zero (Rn= 0) positive feedback is absent (resistor R4between reinvestiruet entrance of the shelter and a common point when shorted). The scheme turns into an ordinary inverting amplifier, the output voltage is determined by the equation
Uo= -E R2/R1< / BR>When Rn= 0, the current through the load is equal to the output voltage divided by the resistance R3, i.e.In= Uo/R3= -E R2/R1R3.From condition (1) implies that
R2/R1R3= 1/R4and thus, finally
In= -E/R4.When increasing the load resistance increases positive feedback, i.e., increases in proportion to the output voltage, and the current through the load is not changed. This is up until the output voltage is less than the maximum allowable under the terms of this operational amplifier.and the output voltage of the operational amplifier Uo= where m = R1/R2= R4/R3< / BR>Using formula (2), easy to install maximum load resistance for which the operational amplifier can provide a specified current.For example, when In= 2 mA, m = 1, R4= = 1 kOhm and the maximum allowable output voltage of the operational amplifier Uo= 10, we get:
Rn= = = 2000 Ohms (56) 1. Gutnikov C. C. Integrated electronics in the measuring devices. L. ; Energoizdat, 1988 , page 70.2. Horowitz P. , hill U. , Art circuitry in 2 volumes, volume I, translated from English. M. : Mir, 1984, pp. 162, 163. The SOURCE of constant CURRENT TO GROUNDED LOAD, containing the first, second, third and fourth precision resistors, the input leads for connection of the input voltage, operational amplifier, a resistor load, the first output of the first resistor is included with one input / output, another input the output is connected to a common point, the other output of the first resistor connected to the inverting input of the operational amplifier and to the output of the second resistor, the second terminal of which is connected to the output of the operational amplifier, one output of the fourth resistor is connected to the output resistor load is a torus and two kinematically associated switch, moreover, the movable contact of the second switch is connected to one output of the third resistor, the other output of which is connected to the output of the trimmer resistor, the other output of which is connected to the output of the load resistor and to the not inverting input of the operational amplifier, and a free output of the fourth resistor is connected to the moving contact of the first switch, its one stationary contact connected to a common point, the other to another input output to a common point connected also fixed contact of the second switch, the other stationary contact is connected to the output of the operational amplifier.
FIELD: electrical engineering.
SUBSTANCE: proposed diode-transistor bridge relates to electrical engineering, particularly to electrical machines and can be used in structural couplings with magnetic bearings. Diode-transistor bridge comprises supply diagonal and load diagonal incorporating at least one inductor coil (8). Note that throttle (7) is additionally included in load diagonal, RC-circuit (9) being connected in parallel to said throttle. Capacitor (12) and power source are connected in said supply diagonal, the latter being connected via separating diode (13). Transistors (5,6) connected into bridge arms have no common connection point. Storage capacitor (12), throttle (7) with RC-circuit (9) and separating diode (13) connected in the diode-transistor bridge in proposed manner, allows a notable reduction in consumed power of the bridge, diametre of conductors connected to power supply and its overall dimensions.
EFFECT: higher reliability, reduced dependence of source weight-and-size upon consumed power.
FIELD: electrical engineering.
SUBSTANCE: integrated power supply voltage converter is intended for efficient conversion of power supply voltage for low-capacity and low-voltage devices that operate from batteries and accumulators to voltages that are less than voltages of chemical power supply sources. Circuit of integrated power supply voltage includes the following components: substrate for circuit arrangement, output unit connected to power supply source and generating output signal, control unit, which controls output unit by means of feedback, unit of low-frequency filter, function of which is to level output signal received from output unit, control unit is equipped with source of reference voltage, voltage divider, clock signal generator and error detector, besides voltage divider transforms signal from reference voltage source and sends it to input of error detector, where signal is also supplied from output unit as well, and further from error detector control signal arrives to permitting input of clock signal generator, and output unit is arranged as based on switched capacitors in the form of two cascades connected in parallel, the first of which comprises capacitor (17), one p-channel transistor (18) and three n-channel transistors (19, 20, 21), the second cascade comprises capacitor (22), p-channel transistor (23) and three n-channel transistors (24, 25, 26), besides transistors of output unit cascades are controlled by two paraphrase signals from clock signal generator "input 1" and "input 2" so that "input 2" signal is sent to transistors (18, 20, 21) and (24), and signal "input 1" is sent to transistors (19, 23, 25, 26), transistors are connected so that depending on level of "input 1" and "input 2" signals, which may either be high or low, at the moment of time, when "input 1" signal is of high level, and signal "input 2" is of low level, current passes through transistors (18, 19) and capacitor (17) from power supply source to output, besides capacitor (17) is in charging phase, and through transistors (25, 26) and capacitor (22) from common bus to output, besides, capacitor (22) is in discharging phase, and at the moment of time, when "input 1" signal is of low level, and signal "input 1" is of high level, current passes through transistors (20), (21) and capacitor (17) from common bus to output, besides, capacitor (17) is in discharging phase, and through transistors (23, 24) and capacitor (22) from power supply source to output, besides capacitor (22) is in charging phase, and at the same time, both in charging or discharging phase of capacitors (17) and (22) current flows in one direction towards outlet of output unit.
EFFECT: achievement of low output voltages and improved efficiency factor at low energy consumption.
FIELD: radio engineering.
SUBSTANCE: voltage switching unit with protection against current overload includes electronic switch which supplies the power to load unit and to overload freezing unit. Overload freezing unit freezes the activation of electronic switch at initial supply of input voltage and provides the deactivation of electronic switch when the current is higher than the specified one. Additionally introduced shaper of delayed pulse unlocks the electronic switch, provides the specified delay relative to the supply of input voltage.
EFFECT: improving reliability of the device owing to excluding the current stabilisation mode at any kinds and modes of load, and enlarging functional capabilities owing to tuning of current commutation time relative to supply of input voltage.
2 cl, 4 dwg
SUBSTANCE: in a stabiliser, comprising an input capacitor, a transistor, a diode, a throttle, a current sensor and an output capacitor, parallel to the input capacitor there are the following components connected in series - an upper stabilitron, a current stabiliser and a lower stabilitron, joined to a negative pole of the input capacitor, parallel to the upper stabilitron there are the following components connected - an interlocking device, connected to an upper comparator, an operational amplifier and a reference voltage divider, a sawtooth oscillator, an upper comparator and an operational amplifier, and a bridge circuit is connected in parallel to the lower stabilitron, including a transistor of an optical transistor and three resistors, and also a lower comparator. At the same time devices are used for galvanic isolation of control elements.
EFFECT: expansion of input voltage range, simplification, reduced cost, increased reliability and convenience of the stabiliser operation.
4 cl, 5 dwg
SUBSTANCE: protection circuit of the power supply unit of a dc voltage apparatus is installed at the output of the power supply unit, and between the positive terminal (3) of the power supply unit and the positive terminal (1) of said apparatus there is a switching element (S1) and an inductor (L1), which is connected between the switching element (S1) and the positive output terminal (1), wherein the inductor (L1) on its side connected to the positive output terminal (1) is also connected to the an output capacitor (C2), and the side of the inductor (L1) connected to the switching element (S1) is connected to a diode (D1), which is connected in parallel to the output capacitor (C2) n the cathode side, and there is also a device for controlling the switching element (S1), which includes the switching element (S1) depending on current measured in the protection circuit.
EFFECT: designing an apparatus which, as a result of connecting units when the apparatus is operating, the absence of current harmonics is determined, and therefore undervoltage on the conductor line.
SUBSTANCE: invention is a device with supply from a solar battery, which includes a battery, at least one photoelectric element (which may be a part of a solar module comprising multiple photoelectric elements) and a DC-perceptive AC device, such as a compact fluorescent lamp. The device with supply from a solar battery may also include the first DC-DC converter, which receives the first electric signal from at least one photoelectric element and provides a charging signal to a battery, and the second DC-DC converter, which receives the second electric signal from a battery and provides for a DC signal of DC supply to the DC-perceptive AC device.
EFFECT: higher efficiency factor.
19 cl, 3 dwg
SUBSTANCE: step-up voltage converter comprises an input circuit with a choke in one of branches, two power keys, two diodes, and a starting key with a resistor shunting it and two in-series output capacitors. In order to improve reliability of semiconductor elements and prevention of the core saturation upon supply of input voltage should be performed in four stages. Unbalanced conditions of the converter operation are eliminated by introduction into the scheme of two auxiliary keys controlled by two auxiliary drivers and two operating amplifiers (OA). A resistor is connected in series with each auxiliary key and each operating amplifier contains series circuits, which consist of a diode and resistor thus ensuring hysteresis of connection and disconnection of the auxiliary keys.
EFFECT: high reliability.
SUBSTANCE: invention relates to the field of electrical equipment and can be used in digital control systems of DC voltage converters with the function of suppression of the hazardous oscillations of output voltage occurring at a certain set of parameters of the system. In the nonlinear dynamics control system the control system consisting of the main subsystem and the control auxiliary subsystem, approximators on the basis of neural networks is connected to the power part of the converter. The converter control signal provides the stabilization of average value of output voltage. In the system the correction of error signal is provided, thus the stabilization of the design dynamic mode (1 cycle) is provided.
EFFECT: ensuring of pre-set nonlinear dynamic properties of the system and pre-set parameters of speed and accuracy of output voltage stabilization in case of refusal from parametrical synthesis.
SUBSTANCE: direct-current voltage converter comprises control field-effect transistor, which gate is shunted by parallel circuit from counterconnected first diode and first resistor while its drain is connected to anode connection point of switching diode and the first output of choke, which second output is connected to the first input pin joined to source of the control field-effect transistor and the first output pin connected through output capacitor to cathode connection point of switching diode, the second output pin and the first output pin of the output voltage divider, which second output is connected to the first output pin meanwhile the midpoint is connected to measuring input of the control unit, which common leg is connected to the first output pin, emitter follower, which output pin is connected to the first output of the second resistor. The circuit is featured by introduction of a coupling capacitor connected between the second output of the second resistor and gate of the field-effect transistor, the first transistor with load resistor in the collector circuit and auxiliary capacitor connected between outputs of the collector and emitter of the first transistor, which base is connected to output pin of the control unit, emitter is connected to the first output pin while collector - to input pin of the emitter follower. At that in the suggested device the control unit may consist, for example, of pulse generator, which output is coupled to input of saw-tooth voltage shaping unit and to the first input of comparator circuit, which second input is coupled to output of saw-tooth voltage shaping unit and its third input is coupled to output of feedback amplifier, which input is connected to input pin of the control unit and its second input is connected to output of the reference element. In operating mode at large pulse ratio of control voltage at the gate of field-effect transistor (low duration of gating pulses) due to introduction of an auxiliary capacitor the control field-effect transistor starts operation in linear mode limiting reduction in duration of control voltage thus preventing loss in stability of regulation by DC voltage stabiliser.
EFFECT: reliability improvement.
3 cl, 3 dwg
FIELD: electrical engineering.
SUBSTANCE: invention relates to electrical engineering and can be used in load time division multiple access systems. Power supply with USB interface comprises: USB interface, smooth switching circuit and DC/DC conversion circuit, which are connected in series. From output of DC/DC conversion circuit power is supplied to loading time-division multiple access system. Power supply source also comprises a capacitor, first end of which is connected between smooth switching circuit and DC/DC conversion circuit, and second end is grounded. Said capacitor is used for limitation of input current of DC/DC conversion circuit. Value of capacitor is selected in accordance with voltage on capacitor, when loading time-division multiple access system is operating or not operating, maximum current allowable for output via a USB interface, input voltage of DC/DC conversion circuit, voltage and current required by load time division multiple access system, and period of operation of load time-division multiple access system.
EFFECT: technical result consists in compensation of power at reduced capacitance in circuit of connector, providing compensation of power, ensuring working parameters of power supply source with USB interface.
8 cl, 8 dwg