JPS62262655A - Power unit - Google Patents

Abstract

PURPOSE:To simplify the constitution of the control part, by inserting the primary winding of a transformer and a transistor into between input and output terminals and connecting the secondary winding of a trnasformer, a serial circuit of a flywheel diode and a condenser into between output and earth terminals. CONSTITUTION:A serial circuit of the primary winding n1 of a transformer T1 and the collector and emitter of a transistor Q1 are connected to between an input terminal 1 and an output terminal 3. On the other, between the output terminal 3 and an earth terminal 4 a serial circuit of the secondary winding n2 of the transformer T1 and a flywheel diode D1 and a condenser C1 are connected in parallel respectively. The voltage set up at the secondary winding n2 of the transformer T1 is used as a driving signal of the transistor Q1.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a Chiatsuba type power supply device.

(Problems that the prior art and the invention are trying to solve) Part 4
Figures 5 and 5 respectively show the schematic configuration of conventional power supply devices, with Figure 4 showing a ringing converter via a transformer, and Figure 5 showing a general chopper. .

Therefore, input terminal 1. Ground terminal 2! ¥! By applying a roughly smoothed DC voltage to output terminal 3. and driving transistor Q to oscillate, output terminal 3. An output is obtained between the ground terminals 4 and a stabilized DC voltage is supplied to the load side.

By the way, in order to stabilize the output voltage, the drive signal for transistor Q must be changed in a direction that cancels out the error between the set value and the actual value. The duty ratio or frequency of the drive pulse is changed according to the error between the output voltage and the set value. Therefore, in addition to the transistor Q that performs the chopper, a transistor for an error amplifier and other circuit elements are required, and the large number of parts makes it difficult to miniaturize the device.

(Object of the Invention) The present invention has been proposed in view of the above points, and its purpose is to simplify the control section without deteriorating the accuracy of output stabilization, and to enable miniaturization. The object of the present invention is to provide a power supply device suitable for surface mounting.

(Means for Solving the Problems) In order to achieve the above object, the present invention connects a series circuit between the primary winding of a transformer and the collector/emitter of a transistor between input and output terminals, and connects the output terminal to ground. A series circuit of the secondary winding of the transformer and a flywheel diode, and a capacitor are each connected in parallel between the terminal and the secondary winding of the transformer, and the voltage generated in the secondary winding of the transformer is used as a drive signal for the transistor. is the gist of the invention.

(Example) DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to drawings showing embodiments.

FIG. 1 shows the basic configuration of the present invention.

In the figure, 1 is an input terminal, 3 is an output terminal, and 2 and 4 are ground terminals, and a roughly smooth DC voltage is applied between the input terminal 1 and the ground terminal 2, and the output terminal 3. A stabilized DC voltage is supplied by connecting the ground terminals 4 to a load. The circuit configuration includes input terminals 1. A series circuit of the primary winding #n of the transformer T1 and the collector/emitter of the transistor Q is connected between the output terminal 3, and the secondary winding n2 of the transformer T1 and the flywheel are connected between the output terminal 3 and the ground terminal 4. A series circuit with the diode D1 and a smoothing capacitor C1 are connected in parallel. Further, the winding direction of the windings @n, , n2 is set in the direction shown by the dots in the figure.

Note that the control section (drive section) of the transistor Q is omitted because several examples can be considered, but specifically, the control section (drive section) of the transistor Q is omitted.
It is constructed as shown in FIG. 3 or 3, and uses the voltage generated in the secondary winding n2 as a drive signal for the transistor Q to form a free-running chopper.

In FIG. 1, the operation related to power supply to the load side is as follows. That is, input terminal 1. When the transistor Q is turned on after a DC voltage is applied across the ground terminal 2, the primary winding n, , ) of the transformer T1
The capacitor C1 is charged through the collector and emitter of the transistor Q, and power is supplied to the load side.

Note that when the transistor Q is turned on and the current flowing through the primary winding n is increasing, the voltage generated at the secondary winding n2 becomes positive on the lower side, and the flywheel diode D1
becomes non-conductive, and no current flows from the secondary winding n2 to the load side. Furthermore, when the transistor Q is turned off, the polarity of the voltage generated at the secondary winding 11tn2 is reversed so that the upper side becomes positive, and a current flows through the flywheel diode D to the capacitor C and the load side. In this way, current is continuously supplied to the load side during the on/off periods of transistor Q.

Next, a specific control section will be explained along FIG. 2.

In FIG. 2, the base of transistor Q is connected to input terminal 1 via starting resistor R1, and resistor R
2 and the secondary winding 151 n 2 via the capacitor C2
．． It is connected to the connection point of the flywheel diode D, and these configurations perform startup, positive feedback, and self-running operation. That is, ■Input terminal 1. When a DC voltage is applied between the ground terminals 2, a starting current flows to the base of the transistor Q through the resistor R2, the transistor Q begins to conduct, and the transformer T8
Current begins to flow through the primary winding 1@n.

■Transistor primary volume! II n! The current flows through the secondary winding. A positive voltage is generated on the lower side, and the positive voltage is positively fed back to the base of the transistor Q via the capacitor C2 and the resistor R2, rapidly turning on the transistor Q.

When the saturation point, which is determined by the constants of the 0 circuit, is reached, the current flowing through the primary winding of the transformer T8 begins to decrease, the polarity of the secondary winding n2 is reversed, and the transistor Q is rapidly turned off.

(2) Again, as in (2), the transistor Q is turned on by the starting resistor R1, and these operations are repeated.

Self-propelled motion is performed through a process such as this.

In addition, the output voltage is set by a Zener diode zD1 connected between the base of the transistor Q and the ground line.
This is done by the diode D2 connected between the emitter and the pace of the transistor Q, and the fluctuation range of the output voltage is regulated. Note that the voltage generated at the secondary winding n2 of the transformer T increases as the output voltage decreases, and conversely decreases as the output voltage increases, so the stabilization operation is also highly accurate. There are some advantages.

Figure 3 shows another configuration example of the drive section, in which voltage is taken out from an arbitrary point by the center tap of the secondary winding n2 of the transformer T, and a resistor R3 is connected in series with the Zener diode ZD. This allows the output voltage to be adjusted to a desired value.

(Effects of the Invention) As described above, in the present invention, a series circuit of the primary winding of the transformer and the collector/emitter of the transistor is connected between the input and output terminals, and between the output terminal and the ground terminal. The series circuit of the secondary winding of the transformer and the flywheel diode and the capacitor are connected in parallel, and the voltage generated in the secondary winding of the transformer is used as a drive signal for the transistor. 1. The configuration of the control section of the transistor that performs the transistor operation is simplified, and the number of parts can be reduced, which has the effect of making the device more compact.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the basic configuration of the power supply device of the present invention, FIGS. 2 and 3 are diagrams showing specific examples of the circuit configuration of the present invention, and FIGS. *A is a circuit configuration diagram of the device. 1...Input terminal, 3...Output terminal, 2
,4...Ground terminal, Ql...Transistor, TI...Transformer, nl, n2...Winding, Dl...Flywheel diode, CI
... Capacitor and 1 other person Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A series circuit of the primary winding of the transformer and the collector/emitter of the transistor is connected between the input and output terminals, and a series circuit of the secondary winding of the transformer and the flywheel diode is connected between the output terminal and the ground terminal. A power supply device characterized in that a capacitor is connected in parallel with each other, and a voltage generated in a secondary winding of the transformer is used as a drive signal for the transistor.