SU1667206A1 - High-voltage power supply source - Google Patents

Abstract

The invention relates to electrical engineering and can be used to power high-voltage nodes and elements of electronic equipment. The purpose of the invention is to increase efficiency by providing switching of the key stage with minimum voltage. Resource transformer 6, master oscillator 1, pulse-width modulator 3, voltage detection unit 7, zero detector 2 and interlock circuit 8 are inserted into the power supply containing the key stage 5, the switching points of the key stage 5 are firmly synchronized with moments of minimum voltage on it in each oscillation period of the resonant transformer 6, which ensures a reduction in switching losses and increases the average conversion efficiency. 2 Il.

Description

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The invention relates to electrical engineering and can be used to power high-voltage nodes and elements of electronic equipment.

The purpose of the invention is to increase efficiency by providing switching of the key stage with minimum voltage.

Figure 1 shows the structural scheme of a high-voltage power supply; figure 2 - timing charts of his work.

The source contains a controlled master oscillator 1, the input of which is connected to the output of the zero detector 2, and the output to the synchronization input of a pulse-width modulator 3. The second input of the latter is supplied with a modulating voltage, which is the difference of some reference voltage parts of the output voltage of the high-voltage rectifier 4. The output of the modulator is connected to the control input of the key stage 5, the output of which is connected to the inputs of the step-up resonant transformer 6 and the node 7 for determining the rate of change of voltage output connected to the input of the zero-detector 2. The blocking circuit 8 is connected to the output of the zero-detector 2, and the output to the second input of the zero-detector 2.

The source works as follows.

Initial start-up is provided by master oscillator 1, the natural frequency of which is obviously lower than the frequency of the oscillatory process of the step-up resonant transformer 6 (Fig. 2a). Under the action of trigger pulses in transformer 6, damped oscillations appear (dashed line in FIG. 26). When oscillations appear in transformer 6, at the output of the null detector 2, trigger signals appear, arriving at the input of generator 1 and synchronizing it. From the output of generator 1, the pulses go to the synchronization input of the modulator 3, the output of which produces pulses of duration determined by the modulating voltage, the difference between a certain reference voltage and part of the output voltage of the high voltage rectifier 4 connected to the output of the transformer 6. The pulses from the output of the modulator 3 arrive at the control input of the key stage 5, controlling the duration of its open state. The node 7 for determining the rate of change of voltage analyzes the output voltage of the key stage 5. The output signal of this node goes to the null detector 2. At the moments when the voltage on the key stage 5 is minimal,

the rate of change of the output voltage of the key stage 5 is zero (FIG. 2b) and the null detector 2 generates the start signals of the generator 1 (fig.2g) and the blocking circuit 8, which locks the null detector 2 for 0.5T to prevent false alarms Tblock T, where T is the period of the oscillatory process of the transformer 6. Due to the impossibility of reducing to zero

0, the dissipation inductance of the transformer after the end of the acting pulse of the key stage appears paratite high-frequency damped oscillations with a frequency higher than the working frequency of the resonant transformer (Fig. 26). The presence of these parasitic oscillations can lead to the appearance at the output of a null detector of spurious synchronization pulses at moments of particular minima and

0 high frequency oscillations. To avoid this, as well as in the case of using a single-ended key scheme to eliminate the operation of the null detector on the maximum voltage

5 frequencies (at these moments, the derivative of the voltage is also zero) a blocking circuit 8 is introduced, which produces pulses that lock the null detector for a time longer than the time during which

0 possible false triggering of the null detector (figd).

Claims (1)

Thus, the key stage 5 in each oscillation period of the step-up resonant transformer 6 includes 5 seconds with a minimum of voltage across it, which reduces power losses during switching on and increases the average efficiency of the high-voltage power supply. Invention Formula 0 A high-voltage power supply containing a master oscillator connected to one of the inputs of a pulse-width modulator, to the other input of which a modulating voltage source is connected, a key stage with a resonant step-up transformer and a synchronization circuit characterized in Efficiency by providing key switching 0 cascade at minimum voltage, the synchronization circuit contains a node for determining the rate of change of voltage, a null detector and a blocking circuit, with the input of the node determining the rate of change Voltage 5 is connected to the output of the key stage, and the output is connected to the first input of the zero detector, the output connected to the input of the master oscillator, and also to the input of the blocking circuit, the output connected to the second input of the zero detector. UB6 / X3 H eight L / L 7 I1 s FULL 2 g Ufoix B ( s -Ј FIG. 2