SU1427520A1 - Stabilized power supply source with built-in protection - Google Patents

Abstract

The invention relates to electrical engineering. The aim of the invention is to increase the reliability and accuracy of current protection. When overcurrent or short circuits in the load circuit at the output of the comparator 10 current limiter, a signal is generated that is applied to the blocking input of the pulse width modulator 6 and ensures that the pulse width of the pulse width modulator 6 is independent of the feedback node signal 5 key safe inverter 1 level. The output voltage of the stabilized source drops, and the output current is determined by the magnitude of the voltage of the source 11 of the reference voltage. After the overload has been removed, the normalization of the output voltage stabilization mode — No, automatically recovers 2 or less. % T ":%": .so.

Description

FIG. /

The invention relates to electrical engineering and can be used to protect power supply sources against overcurrent and short ea N iKaHHU in the load circuit.

 The aim of the invention is to improve the reliability and accuracy of current protection.

FIG. functional block diagram of the source is given; in Fig.2 Explanatory time diagrams.

The stabilizing power supply source with protection includes an inverter with an output transformer 2, rectifier 3 and filter L, the output of the second fo through the feedback node 5 is connected to the control input of a pulse-width modulator (PWM) 6, you - The stroke of which is connected to the input of the formatier 7 pulses of the | control by the keys of the inverter 1 and to the input of the triggering on the falling edge of the pulse of the generator 8 of the sawtooth voltage (HPL) connected in series with the current sensor 9 of the inverter 1 in the chain, one of extreme findings cat The operator is connected to a common point of the source, and the other to the first input of the comparator 10 current limiter, the second input of which is connected to the source P of the reference voltage of the current limiter and the output to the blocking input of PWM 6.

The device works as follows.3

In the pulse-width modulator 6, the sawtooth voltage Ue generated by the internal generator of the modulator 6 (not shown) is compared with the output voltage of the feedback node 5 (Fig.2,%), the PWM output signals 6 (Fig 2 , U.) are fed to the input of the imager 7, which generates control signals for the power switches of the inverter 1, which ensures the stabilization of the output voltage of the power supply. The signals from the PWM 6 output are simultaneously fed to the input of the GTSH 8 to operate on the falling edge of the pulse, ensuring its operation is synchronized to the falling edge of the control pulses (Fig.2, and) The voltage pulses at the output of the current sensor 9 (Fig.2, Ug) are proportional to the load current of the inverter 1, summed with the linearly increasing voltage GIN 8 and fed to one input of the comparator 10 bounded

five

0

five

0

five

0

five

0

five

chitel current. At the same time, the maximum amplitude of the sum signal (Fig. 2, U8 + Ug) does not depend on the duration of the control pulses t, since the amplitude of the total voltage Ug. is defined by the following expression,

. - gt UHMOVLC where Ugr is the output voltage

current sensor proportional to the load current; Un max amplitude

sawtooth voltage. If the total signal of current sensor 9 and FPG 8 is less than the reference voltage of 5 SPHG.2, Ug + Ug), then the comparator 10 of the current limiter does not affect the operation of PWM 6. In case of overload or short circuit in the load circuit At the current limiter comparator 10, a signal is generated that arrives at the blocking input of PSM 6 and ensures that the pulse width of the PWM 6 is independent of the signal from the feedback node 5 at the key level of the inverter 1. Output Voltage: The stabilized power supply source drops, and the junction current is determined by the magnitude of the voltage of the reference voltage source 11. After the overload is removed, the normal stabilization mode of the output voltage is automatically restored.

I

Thus, due to the generation of the sawtooth voltage generator, the triggering input on the trailing edge of the input pulses. The current protection threshold is constant regardless of the duration of the control pulses, which increases the reliability and accuracy of the protection operation.

Claims (1)

Invention Formula A stabilizing power supply with protection that contains an inverter with an output transformer, a spinner and a filter whose output through a feedback node is connected to the control input of a pulse-width modulator, an output connected to the input of the inverter switch control key, a chain of consistently according to the connected current sensor an inverter and a sawtooth generator, one of the extreme terminals of which is connected to the common bus and the other to the first input of the current limiter comparator, to the second input of which the current limiter voltage source is connected, in order to increase reliability and accuracy The protection patches, the pulse-width modulator is made with a blocking input, to which the comparator output of the current limiter is connected, and the sawtooth voltage generator is fuller with the trigger input on the falling edge of the pulse-width modulator. 6sh % tu T P tuTpt t u t A Fri fu t 1x1x1xY1 / / tf T pt tu t tu t S Fri. t  P P Fri fu t pt tu t FIG. 2 pt t u t