JPS5996865A - Power source - Google Patents

Abstract

PURPOSE:To simplify the circuit configuration of a power source by connecting a switching element for driving a sub circuit formed of another output stage in parallel with a switching element for driving the output stage of a main circuit and composing another quasi-stabilized power source in the sub circuit. CONSTITUTION:A main circuit which is composed of a switching power source circuit forming a closed loop has transistors Q1, Q2, a comparator 3, a differential amplifier 4 and an inverting amplifier 5. A transistor Q1' is connected in parallel with a transistor Q1, and a sub circuit is composed of the transistor Q1', resistors R1', R2', a diode D2, an inductor L2 and a capacitor C2. A quasi- stabilized power source of the voltage different from a main circuit is composed of the sub circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a power supply device including a switching power supply circuit forming a closed loop for a stabilized power supply.

Conventional configuration and its problems A commonly used closed-loop switching stabilization power supply circuit is shown in FIG. (VCC) is an unregulated input power terminal such as a battery, and (V, ) is a regulated output power terminal. (1) is an oscillator, (
2) is a sawtooth wave generation circuit that is triggered by the oscillator (1), and (3) is a voltage comparator that compares the potential vc set by the output voltage value of the differential amplifier (4) with the sawtooth wave generation circuit (2). ) and outputs a rectangular wave output, which is input to the base of a transistor (Q2) which is a switching element via an inverting amplifier (5) and a resistor (rl), thereby making the transistor (Q2) conductive. When the transistor (Q2) becomes conductive, the base current of the output transistor (Ql) flows through the resistor (R2), and the transistor (Ql)
) conducts. In this way, a rectangular wave output is obtained at the output transistor (Ql), and it is smoothed by a filter consisting of a diode (D+), an inductor (Ll), and a capacitor f (Ct), and the DC! DC voltage is applied to the output power terminal (vo). is output. This output power terminal (VO)
■ Output output to. is input to the differential amplifier (4) via a variable resistor (VRI) and compared with the output vR of the reference voltage generator (6) to form a closed loop circuit. The load characteristics of this circuit are shown in FIG.

The above switching type stable power supply is highly efficient, generates little heat, and can be easily configured with 75 circuits, making it easy to complicate the circuit.Also, it is difficult to handle loads (circuits) with different output voltages and large currents at startup. When connecting a flowing load (motor, plunger, etc.), there was a problem in that two systems with the same configuration as the circuit shown in Figure 1 were required, making one power supply circuit extremely complicated. Purpose The present invention solves the above-mentioned conventional drawbacks, and achieves the above-mentioned object by simply adding a sub-circuit with a simple configuration to the main circuit. Therefore, in the power supply device of the present invention, a switching element that drives a sub-circuit consisting of another output stage is connected in parallel with a switching element that drives an output stage of a main circuit consisting of a switching power supply circuit forming a closed loop. However, the sub-circuit constitutes a quasi-stable power supply with a voltage different from that of the main circuit.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

Figure 3 is a circuit diagram of the power supply device, in which (Vo) is the output power terminal, (Qi) is the transistor, (Rr) (Rj) is the resistor, (D2) is the diode, (R2) is the interface lid, (
C2) is a capacitor, which is added to the main circuit shown in FIG. 1 of the Kinuta IJ circuit shown in FIG.

Here, if the constant power of the main circuit and the sub-circuit is the same, the load characteristic of the sub-circuit will have a quasi-stabilizing characteristic as shown in Fig. 144. However, if this continues, the negative current It, = I
t, then the output voltage V□=Vo; IL>I
If X, then vO<■d, and conversely, if 'IL<IL', then vO>Vo. This is because the voltage drop when the output stage transistors (Ql) and (Q7) are connected in parallel, and the voltage drop due to the DC resistance of the delta tosliding filter (LIXCI) and (R28C2) vary depending on the load current. Since there is a voltage drop with the Hatake IJu path, it appears in the fifth output voltage. In such a case, since there is no degree of freedom in the output voltage of the 11 circuits, it is not possible to obtain the rated voltage required to obtain the maximum efficiency.

Therefore, the resistance (R1) of the main circuit is made large, for example, 68011, and the duty of the collector waveform of the transistor (Ql) is set (t+tx) as shown in Figure 9, and the output voltage is Set. Then, if the resistance (R()) of the sub circuit is made smaller (for example, 220Ω) than the resistance (R1) of the main circuit, the transistor (Ql)
The duty of the collector is (1+1
2) In short, it is possible to make the output voltage (6) lower than the output voltage (2) 0. Conversely, it can also be made higher.

This utilizes the recombination time of the output stage transistor (Ql) (Ql), and ideally the waveform is as shown in Figure 6, but in reality the resistance (R1) between the emitter and base of the transistor (Ql) is ) can be varied as shown in Fig. 7. However, since the width is about several μs, the effect is small unless the switching frequency is about 100 KHz (T = 10 μs). In Fig. 7, tl is R
1=330Ω, t2 is R1=680Ω, t3 is R1=
The case of 1200Ω is shown in each case. Further, FIGS. 5 and 8 are collector waveform diagrams of the transistor (Q2).

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, by simply adding a sub-circuit with a simple configuration to the main circuit consisting of a switching power supply forming a closed loop, the sub-circuit can generate output without affecting the main circuit. It is possible to configure a semi-stabilized power supply that can vary the voltage, so that the influence of load fluctuations such as the motor as a load of the circuit does not affect the main circuit side,
Maximum efficiency can be obtained for the rated load.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a conventional device, FIG. 2 is an explanatory diagram of load current characteristics of the circuit shown in FIG. 1, FIG. 3 is a circuit diagram of a power supply device according to an embodiment of the present invention, and FIG. An explanatory diagram of the load current characteristics of the circuit shown in Figure 3, Figure 5 is the transistor (Q2)
Figure 6 is the ideal collector waveform diagram of the transistor (Ql), Figure 7 is the ideal collector waveform diagram of the transistor (Ql).
Figure 8 shows the actual collector waveform diagram of the transistor (Q2
), Figure 9 is the actual collector waveform diagram of the transistor (Ql), and Figure 10 is the collector waveform diagram of the transistor (Ql).
) is a collector waveform diagram. (Ql) (01'XQ2)...transistor, (DI
) (D2)...Diode, (LIXL2)...Inductor, (CIXC2)...Conductor yf, (VRI
) = -6f Variable resistance, (RxXRi) (R2) (R
j) - Resistance agent Yoshihiro Morimoto Figure 2 Figure 3 Figure 7

Claims (1)

[Claims] 1. Connect a switching element that drives a sub-circuit consisting of another output stage in parallel with a switching element that drives an output stage of a main circuit consisting of a switching power supply circuit constituting a closed loop, and connect the switching element that drives a sub-circuit consisting of another output stage, and A power supply device configured as a quasi-stable power supply with a voltage different from that of the circuit.