SU760357A1 - Bridge-type transistorized regulator - Google Patents

Description

The invention relates to electronics and automation and can be used in the output stages of pulse devices in systems of automatic control and reversal of the 5 load current, as well as in electronic equipment for various purposes.

Known bridge power regulators containing keys, made according to the scheme of complementary composite transistor; powered from a single source and having additional uses for various purposes to improve the properties of bridge regulators 15 And and [2].

However, in these devices there is no protection against current overloads that occur during starting modes of the load, as well as during its short circuit.

Meanwhile, the elimination of this disadvantage allows significantly; to increase the reliability of regulators and to design bridge bridge circuits for lower currents, which significantly reduces the size of the devices.

The closest to the invention is a bridge power controller with 30

2

protection, containing output keys, made according to the composite transistor scheme, reverse diodes connected in parallel with the keys, passive-locking resistors, shunting base-emitter transitions of transistors, and transistors of the protection circuit, each of which is of the same type with a transistor of the protected key made according to the complementary circuit composite transistor, and is connected by its emitter to the emitter, the collector is connected to the base of the corresponding pre-transistor, and the base is connected to The chain consisting of consecutive and counter-coupled diodes - c. emitter of the output transistor. protectable key [3].

The disadvantages of this device are: unlocking the locked key (and the device as a whole), which, after the disappearance of the overload factor, must be carried out by the control signal itself, i.e. only in pulsed mode of operation, which limits the range of operating modes of the regulator; “prone” of the regulator to self-excitation, eliminated in each specific instance of the regulator

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by dhenie KS chains, almost not amenable to calculation; temperature instability of the limited current level.

The purpose of the invention is to increase the stability of the threshold of protection and the provision of automatic re-arming protection.

This goal is achieved by the fact that “in the bridge power regulator

Overload protection containing a power key bridge at least

- two of which consist of the terminal and prefinal transistors, which have different types of conductivity and are connected according to the composite transistor circuit, and two protective transistors,

• having the same conductivity type as

and the pre-end transistor, and the emitter connected to the emitter of the pre-end transistor of this key, the collector to the base of the pre-end 20 transistor of this key, and the base through a chain of two counter-series-connected diodes to the emitter of the terminal transistor of this key,

re-cocking pulses, measuring resistor, additional transistor, feedback resistor

• 'separating resistor, with the measuring resistor connected in series to the common collector circuit of the terminal transistors of the two specified switches connected to the first input terminal of the device, and the feedback resistor is connected between the base of the protective transistor and the collector of the terminal transistor of the switch diodes of the specified chain through a separating resistor and an additional transistor is connected to the second input terminal, and the base of the additional transistor is connected to the output of the torus pulses recharging. In addition, a stabistor was used as one of the diodes of the indicated chain connected to the base of the protective transistor.

“The drawing is a diagram of the proposed device.

Device 'contains okoyechny tran-ςθ zistors. 1-4 bridge bridge keys, pre-terminal transistors 5-8 bridge circuit keys, reverse diodes 9-12 of the brain circuit, measuring resistor 13, load 14, terminals 15, 16 for connecting the power source ** In polarity indicated in the drawing, 'terminals 17-20 for supplying control signals to the bridge circuit keys from the preamplifier (not shown), protection transistors 21, 22, diodes 23 23-26 comparison circuits (stabilizers can be used as these diodes), temperature stabilized diodes 27, 28 current resistors 29-32, generator 33 im- 45

re-cocking pulses, decoupling- "vanadium transistor 34.

Connections in the proposed scheme of the bridge regulator are characterized as follows.

Transistors 1, 5 and 3, 7 are elements of the upper keys, and transistors 2, 6 and 4, 8 are elements of the lower keys of the bridge circuit. The base of transistor 1 is connected to the collector of transistor 5, the base of transistor 3 to the collector of transistor 7, the base of transistor 2 to the emitter of transistor 6, and the base of transistor 4 to the emitter of transistor 8. The base-emitter transitions of all transistors of keys are shunted by passively locking resistors. To the output 15 of the positive pole of the power source, the emitters of the transistors 5, 7, 21, 22, the cathodes of the diodes 9, 10 and the output of the measuring resistor 13 are connected, the second output of which is connected to the collectors of the transistors 1, 3 and to the terminals of the resistors 31, 32, other terminals are connected to the bases of transistors 21 and 22, respectively. The emitter of transistor 1 is connected to the anodes of diodes 9, 24, the cathode of diode 11 and the collectors of transistors 2 and b, and the load 14 is connected to one of the terminals here, the second output of which is connected to the anodes of diodes 10, the collectors of transistors 4 , 8 and the diode cathode 12. The emitters of transistors 2, 4 are connected to the negative terminal 16 of the power supply,

34 and the anodes of the diodes .11, 12, as well as one of the conclusions (supply) of the generator 33 (for the proposed technical solution it does not matter from what source to supply the generator ·, (for example, when using an integrated microcircuit as a generator, it can be powered from the main source through a conventional parametric stabilizer formed by a resistor and a zener diode). The second output of the generator (control) is connected to the base of the transistor 34, the collector of which is connected through a resistor 29 to the cathode of the diode 24 and the anode of the stabistor 23 , through a resistor 30 - with the cathode of diode 26 and the anode of Stabistor 25. The cathode of Stabistor 23 is connected to the base of transistor 21, and the cathode of Stabistor 25 - to the base of transistor 22. Base of pre-transistors 5,

7 are connected to the cathodes of the diodes 27, 28, respectively. The anodes of the diodes 27, 28 are connected respectively to the collectors of the transistors 21, 22, which are connected respectively to the control signal supply terminals 17, 19. The base of the transistors b, 8, respectively, are connected to terminals 18, 20.

Static state of the bridge power control circuit with the connected power source characteristic характ

76035.7

Rie depending on the control signals received at terminals 17-20 from the transistors of the preamplifier. (the scheme and its operation are not of fundamental importance for this technical solution and therefore are not considered in the description). For example, . the inclusion of transistors 1 and 3 is possible when connecting terminals 17 and 19.

respectively, the negative power supply terminal 16 (via the preamplifier transistors), and the switching on of transistors 2 and 4 - when connecting terminals 18 and 20, respectively, to the positive terminal 15 of the power supply (also through the corresponding included preamplifier transistors). The control signals can arrive at terminals 17-20 in combinations that ensure the inclusion of certain terminal ’transistors and which are dictated by the necessary electrical process in the load; such a combination of signals is prohibited, which causes the simultaneous connection of the terminal transistors of the same bridge circuit rack.

It is advisable to consider the operation of the bridge regulator in two modes: normal mode and load current limiting mode.

In normal operation, in one 30 of the possible states of the terminal transistors (for example, in the presence of signals at terminals 17 and 20, transistors 1 and 4 of the diagonal pair are open) current is flowing through the load from the power supply 35. By alternating the control signals at terminals 17-20 in a certain sequence and changing their duration, it is possible to regulate the average voltage across the load, i.e. in this case, the usual impulse regulation occurs. The state of the elements of the protection circuit in normal mode does not affect the normal operation of the bridge circuit 45, since the periodically unlocking of the transistor 34 does not cause the corresponding unlocking of the transistor 21 due to the higher voltage across the base-emitter circuit of the transistor 21 - -stable 23 than the measuring circuit resistor 13-collector - emitter of transistor 1 - diode 24.

If the load current flowing through the open transistor 1 and the measuring resistor 13) ^e exceeds the allowable value, the voltage drop across the resistor 13 will be sufficient for the transistor 21 to open, which in turn will cause the locking of transistors and 1 ', the voltage between the collector and the emitter of transistor 1 begins to increase, resulting in a breakdown of the stabistor 23, as the case of voltage on the collector-EMF-®5 circuit

* transistor 1 transistor 1 - diode 24 will be · larger than the base-emitter circuit of transistor 21 - stabistor 23. In the furthest open state of transistor 21 (and, therefore, the locked state of transistors · 5 and 1) will be maintained along the stabistor 23 circuit. - resistor 29 - open transistor 34 until the next "narrow" locking pulse (1-2 microns / sec) from the generator 33 arrives at the base of the transistor 34, which will also cause the locking of the transistor 21, and, therefore, unlocking the transistors 5 and 1 under the action of the signal at terminal 17. Through the transistor 1 again start r increased to the allowable current value, then the process repeats transistors locking key, and will be periodically switched on and off key with a frequency determined by oscillator 33.

A similar picture of the current limit is also observed if the current flows through the transistor 3. The cut-off level of the load current specified for the device determines the size of the measuring resistor 13, and its average value (in the limit mode) depends on the equivalent external circuit resistance and frequency generator 33 and can be quite small or equal to the rated current.

Claims (2)

Claim 1. The bridge transistor regulator with overload protection, containing a bridge of power switches, at least two of which consist of terminal and pre-terminal transistors having a different conductivity type and connected in a composite transistor circuit, and two protective transistors having the same conductivity type, that both the pre-terminal transistor and the emitter connected to the emitter of the pre-terminal transistor of a given key, the collector - to the base of the pre-terminal transistor of the given key,. and the base - through a chain of two oppositely connected diodes - to the emitter of the terminal transistor of this key, characterized in that, in order to increase the stability of the protection response threshold and provide automatic re-arming protection, the re-arming pulse generator, measuring resistor ,, optional a transistor, a feedback resistor and a separating resistor, and the measuring resistor is connected in series to the common circuit of the collection of two terminal transistors 7 ..... 760357 These keys are connected to the first input terminal of the device, and between the base of the protective transistor and the collector of the terminal transistor of this switch, a feedback resistor is connected, the connection point of the diodes of the specified chain is connected to the second input terminal through the coupling resistor and the additional transistor, and the base of the additional transistor is connected to the output of the re-armament pulse generator. 2. The regulator for π. 1, characterized in that in quality 10 eight One of the diodes of this chain, connected to the base of the protective transistor, used a stabilizer.