SU1248009A1 - Multichannel power source - Google Patents

Description

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The invention relates to electrical engineering and can be used in secondary power supplies of electronic equipment.

The aim of the invention is to increase the stability of the output voltage and the efficiency of the multichannel power supply.

Figure 1 is a schematic of a multichannel power supply; 2 shows timing diagrams for the operation of the device.

The multichannel power source contains a single-ended converter "1, the primary winding 2 of the power transformer 3 of which is connected to the power supply through a transis-torch key 4, and its secondary windings 5 are connected via smooth diodes 6 of the output channels that drive (generator 8, output connected to the generator U of the sawtooth voltage, the node 10 comparison, to one of the inputs of which is connected

the reference voltage, the comber 11 parator 12, the inputs of which are connected to the outputs of the comparison node 10 and the sawtooth voltage generator 9, and its output is connected to the control of the transition of the transistor switch 4 through the preamplifier 13, the additional choke 14 of the power transformer 3 to which the cut-off diode 15 is connected to a storage capacitor 16, a shunt transistor 18 is connected to the terminals of the first through additional resistor 17, the connection point of the first output of the additional winding 14, the memory The capacitor 16 and the emitter of the shunt transistor 18 are connected to the common power cable of the device, the second output of the storage capacitor is connected to the second input of the comparison node 10, and the base of the shunt transistor 18 is connected via the second additional resistor 19 to the connection point of the second output of the additional winding 14 and the anode the cutting diode 15 ..

My-channel power source works as follows.

The error signal L obtained by comparing the reference voltage Uj and the feedback signal UOP with the memory

Sator 16, enters one

condensate from the inputs of the comparator 12, where you compare it with the input to its other input

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Sawtooth and “c. When the signals are equal, at the time tj, a voltage pulse appears at the output of the comparator 12, which opens the transistor switch 4 of the single-ended converter 1.: The polarity of the diodes 6 and 15 is such that during the open state of the transistor switch 4 pipe disconnected from the transformer 3. The transistor 18, bypassing the storage capacitor 16, is also closed; and there is an accumulation of energy in the transformer 3.. At time t.

 A zero signal appears at the output of comparator 12, which closes transistor switch 4, which leads to a change in the polarity of the voltage on the windings of transformer 3, and through diodes 6 and 15 the energy stored in transformer 3 is transferred to capacitors 7 and 16 and i 5 load. At the same time, a transistor 18 is opened, shunting through: a resistor 17, a capacitor 16. A voltage across a smoothing capacitor) A J and a storage capacitor 16 are proportional to the transformation ratios between the windings. 5 and 14 of the transformer 3 B converter and 1 converter (after the drops voltages on diodes 6 and 15). If for any reason the voltage on one of the capacitors 7 is lower than the voltage applied to it on the other smoothing capacitors 7, then the voltage on the windings of the transformer 3 at the stage of energy transfer is determined by the capacitor 7 with less voltage and energy from transformer 3 is initially completely transferred to capacitor 7 with a smaller reduced

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since the voltages on the other windings 5 are less than the voltages on the corresponding capacitors 7, k. to which they are connected. In the capacitor 7 with a large value of the reduced voltage energy from; transformer 3 does not arrive until its reduced voltage equals the reduced voltage of other channels.

To improve the accuracy of stabilizing the output voltages of the converter channels, it is necessary that the voltage on the capacitor 16 at the stage

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the transmission from transformer 3 to the load repeated the form of the voltage on the capacitors 7, the output channels. Dn of this, it is necessary that the time constant t R be less than the time constant of the load circuit of any of the channels. In addition, loading of the storage capacitor 16 by resistor 17 eliminates its charging due to switching surges on the windings 5 and 14 of transformer 3 caused by scattering inductances, and therefore eliminates the error introduced in this case. maintenance of output voltages;

. By the time tj, the energy accumulated in transformer 3 is completely transferred to the load. At time t, the voltage on the windings 2.5 and 14 of the transformer 3 becomes zero, and the transformer 18 closes. The storage capacitor 16 at a subsequent time interval is connected only to the high-resistance input of the comparison unit 10 and maintains a voltage proportional to the voltages on the output channels. In this case, the time constant of the feedback circuit is tiJJ. - C, - K, x,, where R (xAo the resistance of the discharge of the storage capacitor through the closed shunt transistor 18, the cut-off diode 15 and the input circuit of the comparison node 10, must be greater than or equal to the maximum time constant of any of the output channels, so that the relative discharge of the capacitor 16 is not greater than the relative discharge of the smoothing capacitors 7 of any of the output channels.Otherwise, the stability of the output voltages of the converter 1 is impaired.

At time tj, the sawtooth voltage 3 "becomes equal to the voltage -aU at the output of the comparison node 10 and the described energy storage processes in transformer 3 are repeated.

Decreasing (increasing) the voltage on the output channels decreases (increases) the error signal and increases (decreases) the relative duration of the open state of transistor switch 4 of converter 1, which leads to an increase (decrease) in the energy accumulated in transformer 3 and to increase

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(decrease) voltage on the output channels. Thus, the output voltages of a multichannel power source are stabilized at the 5 base of a single-ended converter with reverse switching of thermal diodes when the input voltage or the load changes in any of the channels.

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Compared with the prototype, the proposed device makes it possible to more effectively stabilize the output voltages in a wide range of input voltage and load variation in any of the channels and to increase the efficiency.

Claims (1)

Invention Formula A multichannel power source containing a single-ended converter, the primary winding of a power transformer of which is connected to a power source via a transistor ny key, and its secondary windings are connected via a fast diode to the smoothing capacitors of the output channels, driving a generator, output connected to a sawtooth generator, the comparison node , to one of the inputs of which a voltage source is connected, a comparator, the inputs of which are connected to the outputs of the reference node and the generator A saw voltage and its output are connected to the control of the transition of a transistor switch through a preamplifier, characterized in that, in order to increase the stability of the output voltages and efficiency, a storage capacitor is connected to the additional winding of the power transformer A shunt transistor is connected through the first inserted resistor, and the junction point of the first additional winding, storage capacitor and shunt transistor emitter is connected The ora is connected to the common power supply bus of the device, the second output of the storage capacitor is connected to the second input of the comparison node, and the base of the shunt transistor is connected to the connection point of the secondary output of the auxiliary winding and the cut-off diode through the second input resistor. fig 2