JPS626420B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a DC stabilized power supply device that takes an unstable AC input signal such as an output signal of an inverter and outputs a signal having a stabilized DC voltage of a predetermined value. The present invention relates to the high frequency switching type DC stabilized power supply device used.

Conventionally, this type of power supply device uses a conversion transformer to step up or step down an unstable alternating current, such as a high frequency inverter output signal, rectify and smooth it, convert it into a direct current voltage, and then stabilize it to a predetermined level by on/off control of the transistors that make up the chopper section. is configured to obtain a regulated DC voltage. However, this configuration requires a rectifier and smoothing circuit in front of the chopper transistor, and the power loss in the rectifier circuit to prevent short circuits on the output side of the conversion transformer is large, which significantly reduces the conversion efficiency of the entire power supply. There is a drawback that it does.

An object of the present invention is to provide a high-frequency switching type DC stabilized power supply device having an extremely novel configuration and principle that can eliminate the rectifying and smoothing circuit at the stage before the chopper transistor.

Another object of the present invention is to reduce power loss by providing a configuration in which the chopper transistor has the function of a rectifier circuit in the preceding stage of the chopper transistor.

According to the present invention, in a device that outputs a signal having a stabilized DC voltage of a predetermined value using an unstable AC as an input signal, a conversion transformer that converts the input signal into first and second signals that are mutually push-pull; a first transistor that switches the first signal in response to a first control signal applied to the control terminal; and a second transistor that switches the second signal in response to a second control signal applied to the control terminal. a smoothing circuit that smooths a signal obtained by superimposing the output signals of the first and second transistors on each other; and a smoothing circuit that detects when the first signal rises and detects when the first signal rises. The first control signal is controlled to turn on the first transistor for a first time determined based on the output signal of the smoothing circuit from the rising point to the next falling edge. a first control circuit that detects the rising edge of the second signal and controls the smoothing circuit from the rising point of the second signal to the next falling edge of the second signal; the second transistor to turn on the second transistor for a second time determined based on the output signal;
a second control circuit that provides a control signal to the second transistor, and as an output signal of the smoothing circuit by controlling the first and second time widths by the first and second control circuits. A high frequency switching type DC stabilized power supply device is obtained, which is characterized in that a signal having a stabilized DC voltage of the predetermined value is obtained.

That is, the present invention connects first and second transistors directly to two output terminals of mutually push-pull first and second signals of a conversion transformer, respectively, and connects the first and second transistors to The first and second transistors are turned on at the same time by turning on only the time required for stabilization from the rising time of the first and second signals, respectively, from the rise to the next fall; That is, the two output terminals of the conversion transformer are prevented from being short-circuited, thereby eliminating the need for a rectifier circuit in the preceding stage of the chopper transistor.

A detailed description will be given below with reference to the drawings.

A conventional high frequency switching type DC stabilized power supply device was constructed as shown in FIG. In Figure 1, 1 is a conversion transformer, 2 and 2'
is a rectifier, 3 and 7 are smoothing capacitors, 4 is a transistor forming the chopper section, 5 is a flywheel diode, 6 is an inductor, 8 is a control
IC, 9 and 9' are output detection divider resistors. If the input signal A of the conversion transformer 1 is a rectangular wave with a period T as shown in FIG. 2A, then a voltage V with a period T as shown in FIG. 2B and C at the output sides B and C of the conversion transformer 1, respectively. The first and second rectangular waves are mutually push-pull. The rectifiers 2 and 2' are for preventing short-circuiting of the push-pull output end of the secondary winding of the conversion transformer 1. The first and second waveforms are smoothed by a smoothing circuit including a smoothing capacitor 3, and at point D become a DC waveform of a constant voltage _V1 as shown in FIG. 2D. This DC waveform is input to the chopper part transistor 4, and the output terminal E of the chopper part transistor 4 is controlled to turn on/off the chopper part transistor 4 by a control IC 8 based on the signal at the connection point of the output detection dividing resistors 9 and 9'. As a result, a rectangular wave of voltage V ₁ with period T' as shown in FIG. 2E is obtained. This rectangular wave of voltage _V1 is smoothed by a smoothing circuit including a smoothing capacitor 7, and the output terminal F of the smoothing circuit is smoothed by a smoothing circuit including a smoothing capacitor 7.
Then, the required stabilized DC voltage V ₀ including a constant ripple component as shown in FIG. 2F is obtained.

In this way, the device shown in FIG.
A rectifier circuit is required, and the power loss caused by the rectifier circuit is extremely large and is one of the causes of a decrease in conversion efficiency.

On the other hand, the high frequency switching type DC stabilized power supply according to the embodiment of the present invention shown in FIG. The structure and principle of this embodiment are quite novel, and the structure and principle of this embodiment will be explained in detail below. If the input signal to the conversion transformer 1 is a rectangular wave with a period T as shown in FIG. 2A as in the case of FIG. This results in first and second rectangular waves of voltage V having a period T that are mutually push-pull as shown in FIGS. 2B and 2C. However, the time (pulse width) from the rise to the next fall of the first and second rectangular waves is T/2.
shall belong to. The first transistor 4 switches the first rectangular wave applied to its collector in accordance with a first control signal applied to its base and outputs it to its emitter. Similarly, the second transistor 4' switches the second rectangular wave applied to its collector in response to a second control signal applied to its base and outputs it to its emitter. The emitters of the first and second transistors 4 and 4' are connected to each other at point E'. That is, a signal obtained by superimposing the output signals of the first and second transistors 4 and 4' is obtained at point E'. this
The signal at point E' is applied via an inductor 6 to a smoothing circuit including a smoothing capacitor 7, where it is smoothed. The first control IC 10 detects the rising edge of the first rectangular wave B, and converts the smoothing circuit from the rising edge of the time (T/2) from when the rectangular wave B rises until the next falling edge. The first time determined based on the voltage obtained by dividing the output signal of 7 by resistors 9 and 9'
The first transistor 4 is turned on for t ₁ (where t ₁ <T/2). Similarly, the second control IC 10' detects the rising edge of the second rectangular wave C and
Time from rising to falling (T/2)
A second time t ₂ (t ₂
<T/2) turns on the second transistor 4'. In this embodiment, the first and second control ICs
By controlling the widths of the first and second times t ₁ and t ₂ by 10 and 10', a signal F having a stabilized DC voltage of a predetermined value V ₀ is obtained as the output signal of the smoothing circuit 7. It is something. In addition, in FIG. 3, 5 is a flywheel diode similar to that in FIG. 1.

The control ICs 10 and 10' operate in conjunction with the rise of the first rectangular wave B and the second rectangular wave C at the push-pull output terminal of the secondary winding of the conversion transformer 1, respectively, and operate in conjunction with the rise of the first and second rectangular waves C at the push-pull output terminal of the secondary winding of the conversion transformer 1, and 4 and 4' are turned on at the same time, that is, the push-pull output terminals of the secondary winding of the conversion transformer 1 are prevented from being short-circuited to each other. Control IC1
When the first and second transistors 4 and 4' are turned on in a time-division manner over the required times t ₁ and t ₂ at 0 and 10', respectively, the voltage waveform at the above point E' becomes as shown as E' in FIG. A pulse of voltage V is obtained twice within one period T. This is because the transmission due to turning on of transistors 4 and 4' occurs once each within one period T. The waveform of FIG. 4E' is smoothed by the smoothing circuit 7, and a signal having a stabilized DC voltage of a predetermined value _V0 as shown in FIG. 2F is obtained as the output signal F.

According to this embodiment, the power consumed by the rectifiers 2 and 2' shown in FIG. 1 can be reduced, so that the input/output conversion efficiency is improved accordingly. For example, when an output of about 10 A is required, in the conventional circuit shown in FIG. 1, there is a loss of about 5 W in the rectifiers 2 and 2', but this loss is reduced in this embodiment.

As explained above, according to the present invention, it is possible to obtain a high-frequency switching type DC stabilized power supply device having an extremely novel configuration and principle in which the rectifier circuit and smoothing circuit in the stage before the chopper transistor are eliminated.
This has the effect that power loss caused by the rectifier circuit can be reduced and conversion efficiency can be improved.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a conventional high frequency switching type DC stabilized power supply device, Fig. 2 is a diagram showing signal waveforms of each part in Fig. 1, and Fig. 3 is a high frequency switching type DC stabilized power supply according to an embodiment of the present invention. FIG. 4 is a circuit diagram of the power supply device, and is a diagram showing the signal waveform at point E' in FIG. 1... Conversion transformer, 2 and 2'... Rectifier, 3... Smoothing capacitor, 4 and 4'... Transistor, 5... Flywheel diode,
6...Inductor, 7...Smoothing capacitor, 8...
...control IC, 9 and 9'...output detection dividing resistor,
10 and 10'...control IC.

Claims (1)

[Claims] 1. In a device that uses unstable alternating current as an input signal and outputs a signal having a stabilized direct current voltage of a predetermined value,
a conversion transformer that converts the input signal into mutually push-pull first and second signals; a first transistor that switches the first signal in response to a first control signal applied to a control terminal;
a second transistor that switches the second signal in accordance with a second control signal applied to a control terminal; and a smoothing circuit that smoothes a signal obtained by superimposing the output signals of the first and second transistors. , detecting the rise time of the first signal, and determining the first signal based on the output signal of the smoothing circuit from the rise time of the time from when the first signal rises until the next fall. a first control circuit that applies the first control signal to the first transistor so as to turn on the first transistor for a time; and a first control circuit that detects the rising edge of the second signal and controls the second signal. the second control signal so as to turn on the second transistor for a second period of time determined based on the output signal of the smoothing circuit from the time of rising to the next falling; a second control circuit that applies the first and second time widths to the second transistor, and the first and second control circuits control the first and second time widths to set the predetermined value as the output signal of the smoothing circuit 1. A high-frequency switching type DC stabilized power supply device, characterized in that a signal having a stabilized DC voltage of .