JPS5963935A - Automatic voltage switching charger - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

The present invention applies when the input power supply voltage is 100V, and even when the input power supply voltage is 260V.
The present invention relates to an automatic voltage switching type charger that can be freely adapted and used without requiring any switching operation even in the case of the above. Conventionally, in this type of automatic voltage switching type charger, the first
As shown in Figures and Figure 2, the on-time of the switching transistor of the transistor inverter is controlled according to the voltage of the connected AC power supply to keep the charging current from the transistor inverter to the secondary battery constant. In the block diagram of FIG. 1, the output of the alternating current power supply AC is rectified by the rectifier circuit f1'+ and then supplied to the transistor inverter (2).
A secondary battery (3) is charged by the output of this transistor inverter (2). Transistor inverter (2)
is a power conversion section (4), a switch capacitor (6), a startup circuit (6), a startup acceleration circuit (7), and a secondary output rectifier circuit (
8) The structure of the transistor inverter (2) itself is generally conventional. Furthermore, in the conventional example heading road in FIG. 1, the power converter (4)
The rectifier circuit (13) that rectifies a part of the output of the switch-on time Ilj calculation circuit WJt12) is operated, and the output of either the switch-on time IIJ calculation circuit (12) or the charging completion voltage detection circuit (ll) is operated. The OR circuit (
actuating the switching control circuit (9) via lO);
This controls the operation of the switch cap (5) of the transistor inverter (2) so that a constant charging current can be supplied to the secondary IR battery regardless of changes in the input voltage. However, such conventional chargers are only for quick charging, and have an arbitrary charging time.The above-mentioned conventional technology is used to adapt to various high and low input voltages. On the other hand, there is a problem in that it is difficult to stably obtain a substantially constant output current. ``This Origination'' was provided in consideration of the above points, and 8.
Automatic voltage switching type charging that allows a charger that requires a relatively long charging time, such as time charging, to always obtain a nearly constant output current despite changes in input voltage. The purpose is to provide equipment. Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 3 shows an embodiment of the vJl circuit of the present invention. This third
In the example circuit shown in the figure, the AC power supply AC passes through the fuse resistor R1 and enters the rectifier bridge (Zec). First, a smoothing capacitor C1 is connected in parallel to the output terminal of the rectifier bridge Rec. The e side passes through the primary winding 11JLs of the oscillation transformer, and the switching transistor Tr+ is connected to the trance ■ side.
From the base starting resistor R2 of the switching transistor Trt, the secondary winding L2 of the oscillation transformer, the base capacitor C2 of the transistor Trl, and the base resistor R3.
The transistor Trl passes through the startup acceleration circuit (7) consisting of
leads to the base of A series circuit of a capacitor C3 and a resistor R4 connected in parallel to the primary winding L1 is a spike 1 absorber that absorbs the high voltage spike that occurs in the primary winding L1 when the transistor Trl is turned from on to off. This circuit and the primary winding Ll form a stain force converter (4
) is configured, and switch capital (5) is a transistor Trl.
, the starting circuit (6) is a resistor R2, and the secondary output rectifier circuit (8)
are each constituted by a tertiary winding L3 and a diode Do. In addition, the transistor Trl and the diodes Di, D2 are one three-way resistor RED, RE of the transistor Tr1.
2, it is a performance improvement circuit 051 which operates by detecting the primary current flowing therein. Two more 1
The emitter resistance switching circuit (

[6) consists of L-C. Thus, the voltage generated in the output winding 1JL3 of the C oscillation transformer is rectified by the diode Do to flow a charging current to the secondary battery (3). In addition, in the embodiment of FIG. 3, the base voltage stabilizing circuit (14) according to the gist of ``Kiori'' is configured as a parallel control type constant voltage circuit.
It is composed of a Zener diode D3, a diode D4, and a resistor R5, and it is desirable that a Schott diode be used as the diode D4. Thus, in this embodiment circuit of FIG. 3, the AC input passes through the fuse resistor R1, is full-wave rectified by the rectifier bridge Rec, and is smoothed by the comb C1. Is this input voltage true? 7. Power conversion is performed by turning on and off the transistor Tr+ to generate high-frequency alternating current, and discharging the magnetic energy A- accumulated by the primary winding Ll through the tertiary winding L3 while the transistor Tr1 is off. This is what we do. Thus, at time 1=0, the resistance R2
The transistor Tr is passed through the secondary winding L2 and the resistor R3.
The starting current IBS flows through the base of the transistor Tr.
t is turned on, collector current IC flows, and induced electromotive force is generated in primary winding Ll. That is, IC VIN""Lt (Lt: primary winding interface) (1)]■=, and from this formula f1+. When the transistor 'I''rl enters the conduction region, a voltage is generated in the secondary winding L2 that applies positive feedback to the transistor Tr+ due to the transformer action, and the collector current increases according to equation (3). However, when the transistor 'pr+ is saturated and IC=hpH・■B, the collector current stops increasing, and due to the transformer action of the primary and secondary windings LL and L2, the transistor TI'l
turned off due to an emergency. Here, an excitation current flows through the transformer until just before the transistor 'l'rt is cut off, and as the current is suddenly cut off by the transistor cut-off, a back electromotive voltage is generated, and a tertiary It is discharged through winding L3. Figure 4 shows the base voltage stabilizing circuit (1
4) When the input voltage is 150V or less, the voltage and current waveforms of each part are shown in Figure 4 (INO) and 1.
Cases of 5 oV or more are shown separately in the same figure (O).
In Fig. 4 a) tl), (a) is the collector current Ic,
, (b) shows the collector voltage VCE% of the transistor Tr+, (c) shows the output current 0, and (d) shows the base circuit voltage VX of the transistor Tr+. Thus, in a circuit that does not have a base voltage stabilizing circuit (I4) like this, there is of course no characteristic problem when the input voltage is around 100V, but when this input voltage is around 15V,
Problems arise when the temperature exceeds 7°. That is, as shown in equation (3) above, the collector current LC increases in proportion to the input voltage VC, and therefore the energy stored in the primary winding L1 increases and is released from the output winding L3. The output current becomes very large in proportion to the input voltage VIN. In addition, when the transistor Trl is cut off from an on-state disturbance, the voltage spike applied to the transistor Tr+K is proportionally high, so that this transistor'
There is a problem in that l'rl requires high voltage resistance performance. Therefore, in the present invention, a base voltage stabilizing circuit 04) as shown in FIG. 3 is inserted and connected between the base of the transistor Tr+ and the startup acceleration circuit (7). Fifth
The figure shows the current and voltage waveforms at each part in this case, as shown in Figure 5 (
The figures are shown separately for the case where the voltage of A2 is 150 V DC or less, and the case where the input voltage of (0) is 150 V DC or more, respectively. In A) and B of the same figure, (a) is Collector current, (b) is collector-emitter voltage VCE %
(C) shows the output current 0, and (d) shows the collector voltage vX of the transistor Tr3. Further, FIG. 6 shows waveforms of various parts similar to those in FIG. 5 in the case of commercial frequency input. Thus, as is clear from the comparison of Fig. 4 with Figs. 5 and 6, the 1-base voltage stabilizing circuit (
Due to the operation of the parallel control type constant voltage circuit (14), as the input voltage increases, the off period of the transistor T r s becomes longer and the on period becomes shorter. This is because the induced voltage at the secondary winding of the base of transistor Tr+ increases in proportion to the input voltage, but due to the influence of the base voltage stabilizing circuit (14) in Figure 5 ([]l)
), the Zener voltage when the transistor Trl changes from off to on is Vz, l-transistor T
If the base voltage of r3 is VI3F, it is %
The induced voltage is clamped at a voltage of (VZ+VBE) and always remains at a constant value even if the input voltage is degraded. In this way, since the base voltage is kept constant, the discharge period of the output current Ii1 discharged from the tertiary winding L3 is changed. That is, as the off-period of the transistor Tr+ becomes longer, its on-period becomes shorter.
The average value of the collector current of l is approximately constant with respect to the input voltage. In addition, the induced voltage generated in the secondary winding L2 is completely discharged as a current, so the high voltage spike generated in the primary winding L1 is suppressed by the transformer action, as shown in Figure 4. This is shown by comparing (0) and (b) in the figure with FIGS. 5 and 6. Further, the diode D4 of the base voltage stabilizing circuit (14) clamps the reverse bias value to the forward voltage VF of the diode D4 when the transistor Trt is off, that is, the base of the transistor Tr is reverse biased. This prevents self-oscillation from becoming unstable due to the application of an excessive reverse bias. FIG. 7 shows a circuit diagram of a second embodiment of the present invention, and shows a base voltage stabilizing circuit. An example is shown in which the circuit (14) is constructed using only the Zener diode D3, and although the function is slightly inferior to that of the circuit of the embodiment shown in FIG. 3, it achieves approximately the same effect. As shown in the figure, a base voltage stabilizing circuit is provided between the base of the switching transistor and its startup acceleration circuit, so when the input voltage increases, the off period of the transistor becomes longer. Its on-period is shortened, the average value of the collector current can be kept almost constant, and it is possible to supply an almost constant output current even with large or medium changes in the input power supply voltage. It can be freely used for power supply voltage circuits.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the conventional example. FIG. 2 is a specific circuit example diagram of the same as above. FIG. 3 is a circuit diagram of the first embodiment of the present invention. ~ (The crests indicate the operation when the input voltage is 150 V DC or lower and 150 V DC or higher in the comparative example, respectively.) Figure 5 (A) The input voltage of the example is DC150V or less and D
Figure 6 (Inno(-)
Figure 7 is a circuit diagram of the second embodiment of the present invention when the input voltage of the first embodiment is below 0150V and above 150V. In the figure, AC is an alternating current power supply, L3 is the tertiary winding of the oscillation transformer, (2) is the transistor inverter, (3) is the secondary battery, Tr+ is the transistor, (6) is the startup acceleration circuit, +1
4) is a base voltage stabilizing circuit, Tr, + is a transistor (for control), DJ is a Zener diode, R5 is a resistor,
D4 is a diode. Agent Patent Attorney Ishi 1) Chapter 7 Chapter 4 (A) (Ron No. (A) c CE x Figure 5 (B) (A) Ic CE x Figure 6 (B)

Claims (3)

[Claims] (1) It has a transistor inverter that operates in zero-sink oscillation using a DC obtained by rectifying an AC power source as a driving power source, and generates a high frequency output in a tertiary winding for output provided in an oscillation transformer, In the inverter type charger that rectifies the high frequency output to charge the secondary battery, a switch: /
1. An automatic voltage switching type charger, characterized in that a base voltage stabilizing circuit is provided between the base of the Yuzuki transistor and its startup acceleration circuit, and the output current is made substantially constant with respect to changes in input voltage f. (2) The base voltage stabilizing circuit includes a control transistor whose collector collector is connected to the base 0 emitter of a switch transistor, and a Zener diode connected between the collector emitter of the control transistor; Claims characterized by comprising: a resistor connected between the base and the base of the control transistor; and a diode connected in parallel between the collector and emitter of the control transistor. @
The automatic voltage switching type charger described in item 1. (3) Claim 1, characterized in that the base voltage stabilizing circuit is constituted by a Zener diode, the cathode of which is connected to the base of a switcher transistor, and the anode is connected to one of the zener diodes. The automatic voltage νJ convertible charger described in Section 1.