JPS586375B2 - Jiyuden Kairo Kosei - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a charging circuit configuration using a ringing choke type transistor inverter, and its purpose is to detect fluctuations in the power supply voltage and detect it when the voltage is high above a certain level. The object of the present invention is to provide a charging circuit configuration in which an appropriate charging current can be obtained even when the power supply voltage is different by stopping the oscillation operation of the electric circuit during the high voltage period.

The present invention will be explained in detail below using one example.

In the charging circuit configuration of the present invention, a so-called ringing choke type transistor inverter is used in the charging circuit 1, and the charging current is controlled by intermittent oscillation of the transistor inverter.

In FIG. 1, a charging circuit 1 includes an oscillation transformer consisting of a collector winding LC, a base feedback winding LB, and an output winding LO wound on the same core with the polarities shown, an output transistor T1, and an output transistor T1. a diode D2 connected in parallel to the rechargeable battery B via the output winding LO, rectifying the output generated at the output winding LO and supplying charging current to the battery B to be charged;
Spike removal capacitor C3 and resistor R1o, bias resistors R5 and R8, speed-up capacitor C2
etc. constitute an inverter circuit.

The diode D1 constitutes a rectifying power source, and the AC power source is half-wave rectified.

However, when the battery B to be charged is uncharged and the voltage across it is low, for example, when an AC power source of 100V is turned on, the pulsating current voltage output from the diode D1 is applied to the power supply input terminal of the charging circuit 1, and a predetermined voltage is applied to the charging circuit 1. When the voltage increases, a starting current flows through the resistor R and the base feedback winding LB to the base of the output transistor T1.

Therefore, the output transistor T1 performs a switching operation,
A current flows through the collector winding LC of the transistor T1, the emitter, the resistor R2, and the circuit of the charged battery B, and a very small voltage is applied to the collector winding LC, and this voltage causes the base feedback winding LB to A voltage is induced in the output transistor T1, resulting in a further increase in the base current and a larger collector current flowing through the output transistor T1.

Then, the relationship between the collector current ■c, base current ■B, and DC amplification factor hFE of the output transistor T1 is IC=hF
When E・■ becomes 8, that is, the collector current ■.

When saturated, the feedback output of the base feedback winding LB rapidly decreases, the output transistor T1 is driven in the off direction, and the output transistor T1 enters the cut-off state.

At this cut-off time, the energy stored in the core of the oscillation transformer generates an output in the output winding LO, and this output is rectified via the diode D2 to charge the battery B to be charged.

Then, the voltage in the reverse bias direction of the output transistor T1 that had been generated in the base feedback winding MLB disappears, and the capacitor C2 is further energized by the resistor R5, and the transistor T
1 becomes forward biased, the transistor T
1 turns on, collector current begins to flow, and the same process repeats.

Here, the second control circuit 3 in FIG. 1 is the charging circuit 1 described above.
The charging circuit 1 is controlled by detecting the voltage of the half-wave rectified power supply supplied by the diode D1 and bypassing the bias current to the output transistor T1.

That is, the pace emitter voltages at the start of conduction of transistors T4 and T5 are respectively vBE4VBE5, the voltage of battery B to be charged is vB, and the terminal voltage of capacitor C1 (i.e., power supply voltage) is v.
When c is reached, the transistors T4 and T5 become conductive, and the oscillation of the charging circuit 1 is stopped.

Therefore, if the set value of the power supply voltage is selected, if the power supply voltage rises above this voltage, charging can be stopped at that point.
For example, if the transistors T4 and T5 are set not to turn off when the 100V AC power is applied, the output winding L
.

The charging current ■o flowing to the battery B to be charged via the diode D2 and the diode D2 is as shown in FIG. 2b.

Now, the first control circuit 2 consists of a resistor R2 and a Zener diode Z.
This constant voltage is divided by a resistor R3 and a series circuit of diodes D3, D4, and D5, and the divided voltage is applied to the base of the transistor T3, which is connected in series to the emitter of the transistor T3. When the charging voltage of the battery B to be charged is lower than the forward drop voltage of the diodes D3, D4, and D5, the transistor T2 is turned on, and this turns off the transistor T3 connected in parallel to the resistor R8 of the charging circuit 1, and vice versa. When the voltage of rechargeable battery B becomes higher than the forward drop voltage, transistor T2 is turned off and transistor T3 is turned on, cutting off the base current of output transistor T1 of charging circuit 1 and stopping its oscillation operation. , the forward falling voltage is applied to the battery B
This is the reference voltage to be compared with the current voltage.

R4 is the base resistance of transistor T3.

When the charging described above progresses and the voltage of the charged battery B exceeds the reference voltage, the first control circuit 2 operates to cut off the pace current of the output synister T1 of the charging circuit 1 and stop the oscillation operation.

Therefore, after this, the charging current flows to the battery B to be charged only through the resistor R, and the transistor T3, but its value is the resistor R5.
It is limited and small.

When the charging voltage of the battery B to be charged decreases due to natural discharge or the like and becomes below the reference voltage, the transistor T2 of the first control circuit 2 is turned on, and the transistor T3 is turned off.
The base current is again caused to flow through the base of the output transistor T1 of the electric circuit 1 to perform an oscillation operation, and charging by the output winding LO is restarted.

In this way, after the full discharge, the discharge circuit 1 performs an oscillation operation intermittently to compensate for the natural discharge.

Next, if the AC power supply has a high voltage such as 200V, there will be a period in which the pulsating voltage increases to a voltage that enables the transistors T4 and T5 of the second control circuit 3 to turn on, and during that period, the transistors T4 and T5 will be turned on. , T5 are turned on, and during the on period, the base current of the output transistor TI of the rectifier circuit 1 is cut off and oscillation is stopped.

Therefore, when the voltage of the AC power supply is high, the rectifier circuit 1 is turned off during the period when the pulsating voltage is higher than the on-operation setting voltage of the transistor T4.

While the transistors T4 and T5 of the second control circuit 2 are on, a current flows to the battery B to be charged via the resistor R5 and the transistor T5, but the current is limited by the resistor R5 and its value is small.

When the voltage of the battery B to be charged rises in this manner and reaches a predetermined level, the transistor T3 of the first control circuit 2 is turned on, and the transistor T3 is turned on, giving priority to the operation of the second control circuit 3. Output transistor T of charging circuit 1
The base current of the charging circuit 1 is cut off, and charging by the charging circuit 1 is stopped.

When the voltage of the charged battery B decreases due to natural discharge and the transistor T3 of the first control circuit 2 is turned off,
While the transistor T5 of the second control circuit 3 is in the off-operation period, the base current flows again to the base of the output transistor T1 of the charging circuit 1 and starts oscillation.

In this way, it is possible to make the average electric current substantially the same as when the power supply voltage is 100V, for example.

Figure 2a shows the output waveform of the diode shop, and in Figure 2a, A shows the case of a 100V AC power supply, and Figure 2A shows the case of a 200V AC power supply.

Figure b shows the electric current ■ during normal charging when the AC power source is IOOV.

, and C in the figure shows charging current ■ during normal charging when the AC power source is 200V.

shows. Figure 3a shows the output transistor T during oscillation operation.
Figure 1 shows the collector-emitter voltage waveform of 1, Figure b shows the waveform of its collector current c, and Figure C shows the waveform of the collector-emitter voltage of diode D2.
The time scale of FIG. 3a is greatly expanded compared to the time scale of FIG. 2.

In FIG. 1, L1 and C1 are a choke coil and a capacitor for noise prevention, and R1 is a resistor for circuit protection.

Furthermore, a capacitor may be connected in parallel to the resistor R7 of the second control circuit 3 in FIG. 1 to change the operation of the transistor T4.

The present invention includes a charging circuit configured as described above, a first control circuit that detects the charging voltage of the battery to be charged and controls the charging circuit, and a first control circuit that detects the power supply voltage and controls the charging circuit when the voltage exceeds a certain voltage level. Since the first control circuit prevents overcharging of the battery to be charged, and the second control circuit prevents excessive charging current from flowing to the battery to be charged when the power supply voltage is high. Compared to systems that perform control by dissipating excess power through heat loss, it is only necessary to control the oscillation of the charging circuit consisting of an inverter circuit, so losses in high voltage parts are extremely low. Therefore, the heat dissipation plate and the like are small, and the entire device can be miniaturized, and it can be incorporated into a small portable electric appliance such as an electric shaver. If set to an appropriate value, it can be used for both low-voltage areas such as Japan and high-voltage areas such as Europe, which is very useful for travelers. This has the advantage of preventing the battery from being destroyed.

[Brief explanation of drawings]

Fig. 1 is a specific circuit diagram of an embodiment of the present invention, Fig. 2a,
Figures b and c are time charts of the AC power supply voltage and charging current as above, and Figures a, b, and c are time charts of each part of the charging circuit, where 1 is the charging circuit, 2 is the first control circuit, and 3 is the time chart of the charging circuit. 2
The control circuit and B are the batteries to be charged.

Claims (1)

[Claims] 1 Connect the series circuit of the collector winding of the oscillation transformer, the output transistor, the reverse diode, and the output winding of the oscillation transformer to a rectifying power supply, and connect the series circuit of the output winding and the diode to the rectifier. The rechargeable batteries are connected in parallel, and the base feedback winding of the oscillation transformer is connected to the base of the output transistor to give a base current through the base feedback winding of the output transistor, and the output of the output winding is rectified by the diode. The charging circuit is equipped with a ringing choke type transistor inverter that supplies the voltage to the battery to be charged, and compares the charging voltage of the battery to be charged with a reference voltage, and when the charging voltage of the battery to be charged exceeds the reference voltage, the output transistor is activated. a first control circuit that cuts off the base current supplied to the base; and a second control circuit that detects the power supply voltage of the rectified power supply and cuts off the base current that is supplied to the base of the output transistor when the voltage exceeds a certain voltage level. A charging circuit configuration characterized by comprising: