JPS58149521A - Power supply device - Google Patents

Abstract

PURPOSE:To facilitate making the device small-sized and make it difficult to be affected by the load state to prevent the generation of a waveform distortion, by giving the switching function in a prescribed frequency and the output stabilizing function to one power system. CONSTITUTION:The square wave output having a prescribed frequency generated in an oscillating part 1 is inputted to the base of a driving transistor TR21 to switch it. A comparator 25 applies the differential signal voltage between the AC output detection signal from an output detecting part 5 and a reference voltage Vref to the collector of the TR21 through a resistance 23 to control the emitter current of the TR21. Consequently, the TR21 drives a TR3 with the frequency of the oscillating part 1 and the current of the comparing part 25, and the TR3 switches the current, which has the frequency of the oscillating part 1 and is controlled, for a primary winding 41 of an output transformer to generate a stabilized AC output in a secondary winding 42.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power supply device that stabilizes and outputs alternating current or direct current with a constant voltage, constant current, etc., and in particular controls one output section with separately generated frequency output and stabilized output. The present invention relates to a power supply device that generates a stabilized AC output with a constant frequency and constant duty, or generates a stabilized DC output by further adding a rectifier.

Conventionally, as a power supply device that stabilizes and outputs voltage, current, etc., (1) the primary winding of the output transformer is driven by a main switching transistor that is driven by an oscillation section that oscillates at a predetermined frequency and regulates the frequency; The current is switched to generate an AC output in the secondary winding of this output transformer, and this AC output is sent to a regulator (series control or switching control) inserted into the primary DC power supply line via an output detection circuit. (2) stabilize the AC output by controlling the DC voltage fed back and applied to the primary winding of the output transformer; (2) regulating the voltage or current of the AC output by controlling the frequency or duty ratio; Stabilizing substances are known.

However, the former requires two power systems: the regulator section and the main switching transistor, which increases costs, and if heat dissipation is required, the two power systems must be isolated, making it difficult to downsize. There were some inconveniences such as: On the other hand, in the latter case, when controlling the frequency, the impedance changes due to changes in frequency when the load is capacitive, and when controlling the tute ratio, the output waveform changes when the input voltage or load changes. There was an inconvenience.

The present invention has been made in view of the above-mentioned problems with the conventional type, and it is possible to simplify downsizing by integrating the power system, and to keep the frequency and duty ratio of the AC output constant to reduce the influence of load conditions. The purpose is to prevent waveform distortion from occurring due to input terminal or load fluctuations.

In order to achieve this object, the present invention includes a transistor that switches a DC voltage, an output transformer provided in connection with this transistor, and an oscillation section that generates an oscillation output that turns the transistor on and off at a predetermined frequency. , is provided between an output detection section that generates a detection output corresponding to the output of the output transformer, the output terminal of the oscillation section, and the base of the transistor, and adjusts the base current of the transistor according to the detection output of the output detection section. negative feedback l
The present invention is characterized by comprising a control section that controls the above.

The present invention will be described in detail below using the drawings.

FIG. 1 is a circuit diagram of an AC power supply device according to an embodiment of the present invention. The AC power supply device in FIG. 1 includes an oscillation section 1, a control section 2
, an output transistor 3 for power amplification, an output transformer 4, an output detection section 5, and the like.

The oscillator 1 consists of an astable multivibrator, for example.
A rectangular wave output with a preset frequency and tute ratio is generated by an external resistor 11, a variable resistor 12, and a capacitor 13, and is provided to the control section 2.

The control unit 2 includes a driving transistor 21, a resistor 22, 23,
It is equipped with a reference voltage source 24 and a comparison section 25, and the base current of the output transistor 3 is not controlled in a negative feedback manner according to the detection output of the output detection section 5, which will be described later. The collector is connected to the output of the comparator 25 via a resistor, and the emitter is connected to the base of the output transistor 30.

The ratio e section 25 includes a comparator 251, and an externally connected reference voltage source 24, for example, a reference voltage V of a constant voltage diode.
ref and the DC voltage from the output detection section 5 described above are compared, and the error voltage is outputted and applied to the collector of the driving transistor 21 via the resistor -23. Note that the emitter follower of the transistor 252 is the comparator 25.
This is to reduce the load on 1.

The output transistor 3 constitutes a power multiplier with a grounded emitter, and switches the current in the primary winding 41 of the output transformer 4 in accordance with a signal from the control section 2.

The output transformer 4 generates an AC output in the secondary winding 42 according to a change in the primary winding current, and the output detection unit 5 detects desired physical quantities to be stabilized, such as the voltage and current of this AC output, and converts it into a DC voltage. Convert and output.

The configuration of the output detection section 5 differs depending on the physical quantity to be detected, but known configurations can be used for these configurations.

Next, the operation of this device will be explained. A rectangular wave output of a predetermined frequency (for example, 50 oHz) generated by the oscillation section 1 is inputted to the base of a driving transistor 21, and this transistor 21 is switched at the predetermined frequency. On the other hand, the comparator 25 applies the error signal pressure between the AC output detection signal from the output detector 5 and the reference voltage Vref to the collector of the transistor 21 via the resistor 23, so that the collector of the transistor 21 receives a normal current. Controls the emitter current.

Therefore, the transistor 21 drives the transistor 3 at the frequency specified by the oscillation section 1 and the current specified by the comparator section 25, and the transistor 3 switches the controlled current at the above frequency to the output transformer primary winding 41. output!・Lance secondary winding 421 Stabilized AC output such as voltage or current (e.g. 500H2, AC4, OKV
, 500 μA sine wave output).

FIG. 2 is a circuit diagram of an AC power supply device according to another embodiment of the present invention. This AC power supply apparatus has a power system, that is, an output section, etc. of the apparatus shown in FIG. 1 of a push-pull type.

For this reason, in the device shown in FIG. 2, the driving transistor 21' and output transistor 3', etc., which operate in opposite phases to the driving transistor 21 and output transistor 3, etc. of the device shown in FIG. At the same time, the primary winding 41' is further wound around the output transformer 4 so that the DC power supply terminal becomes an intermediate tap.
I have set it up. Then, the base of the driving transistor 21' is connected to the collector of the driving transistor 22 through the resistor 22', and an inverted signal is input to the oscillator 10, and the driving transistor 21' is connected to the collector of the driving transistor 22 through the resistor 22'.・Similar to the Lancistor 21, the collector is connected to the output terminal of the comparator 25 via the resistor 23', and the emitter is directly connected to the base of the output transistor 3' (8).The emitter of the output transistor 3' is grounded. , the collector is connected to the primary winding 41'.

The operation of the AC power supply device shown in FIG. 2 is the same as that of the device shown in FIG. 1 with respect to the parts having the same reference numerals as those in FIG. The explanation will be omitted since the components operate in exactly the same manner except that they operate in the opposite phase to the components indicated by the numbers.

FIG. 3 is a circuit diagram of still another embodiment of the present invention. This AC power supply device has the base and emitter of the driving transistor 21 of the AC power supply device shown in FIG. 1 replaced, but since its operation is the same as that of the device shown in FIG. 1, a description thereof will be omitted.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be implemented with appropriate modifications without changing the gist. For example, in the above-mentioned embodiment, the present invention was applied to a stabilized AC power supply, but a DC power supply in which the voltage, current, etc. are stabilized by rectifying the output of the secondary winding 42 of the output transformer is shown. It may also be operated as a device. In this case, the output detection section 5 can be connected to a desired side, either the AC side or the DC side.

As described above, according to the present invention, a single power system has a switching function at a predetermined frequency and an output stabilization function, and therefore miniaturization is possible.

Heat dissipation design is also easy. Also, this results in a cost advantage for dogs. Furthermore, since the frequency and tune ratio are constant, it is unaffected by input voltage and load fluctuations, and its characteristics have been improved compared to conventional products, making it suitable for applications requiring high precision.

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[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an AC power supply device according to one embodiment of the present invention, FIG. 2 is a circuit diagram of an AC power supply device according to another embodiment of the present invention, and FIG. 3 is a circuit diagram of an AC power supply device according to another embodiment of the present invention. FIG. 2 is a circuit diagram of an AC power supply device according to an example. ■...Oscillating unit, 2...Control unit, 21, 21
'...Drive transistor, 3, 31--Output transistor, 4...Output transformer, 41, 41
'...Primary winding, 42...Secondary winding, 5-...
Output detection accent patent applicant Toshiba Tunzai Co., Ltd. Agent Patent attorney Tatsuo Ito 〃 Tetsuya Ito

Claims (1)

[Claims] 1. A transistor that switches DC voltage; An output run support provided in relation to this transistor; An oscillation section that generates an oscillation output that turns on and off the transistor at a predetermined frequency; an output detection section that generates a detection output corresponding to the output of the output transformer; A power supply device comprising: a control section that performs negative feedback control; 2. The control section includes a second transistor that generates an error signal according to the detection output and drives the transistor connected to its emitter according to the error signal and the oscillation output. The power supply device according to item 1. 3. The second transistor has the oscillation output at its base,
3. The power supply device according to claim 2, wherein the error signal is manually input to the collector. 4. The second transistor has the error signal at its base;
3. The power supply device according to claim 2, wherein the oscillation output is manually supplied to the collector.