JPS593108B2 - charger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a charger having a charge display means, and its purpose is to visually confirm whether charging is in progress or whether charging has been completed by changing the lighting mode of a light-emitting display element, and furthermore, the present invention relates to a charger having charging display means. To provide a charger whose display means can be configured with a simple circuit.

The present invention will be explained below using an example circuit.

FIG. 1 shows a circuit of one embodiment, including a step-down circuit 1 consisting of a step-down transformer T that steps down the commercial power supply voltage, and a diode D connected to the output of the step-down circuit 1. , Do full-wave rectification circuit 2
, a switch circuit 4 that connects the battery 3 to be charged to the rectifier circuit 2 via a switching element SCR such as a thyristor 5, a gate drive circuit 5 that drives and controls the switching element SCR, and a diode group D1. A charging circuit section for charging the battery to be charged 3 is formed by a reference voltage generation circuit 6 which amplifies the obtained reference voltage Vref using an operational amplifier OP and outputs it to the switch circuit 4 via the gate 10 drive circuit 5. The switching element SCR
compares the input from the gate and drive circuit 5 side with the battery voltage ED, performs a switching operation, and
This will control the charging current flowing from the battery 3 to the battery 3 to be charged. The charging display circuit 1 includes a reverse current blocking diode D in a series circuit between the switching element SCR and the battery to be charged 3.
2. A series circuit consisting of a Zener diode ZD, a resistor R1, and a capacitor C that constitute the CR integration circuit are connected in parallel, and the capacitor C and the resistor R1 are connected in parallel. A switching element Tr consisting of a transistor whose base is connected to the connection point of 2 through a resistor R2 is connected in parallel through a resistor R25, and a light emitting display element LED consisting of a light emitting diode is connected in parallel to this switching element Tr. It is composed of However, in the circuit shown in Figure 1,
Reference voltage Vref and output voltage V of reference voltage generation circuit 6.
If the relationship is 10VoR4-1(l+-), then the output voltage V.

The difference between VrefR5 and battery voltage ED is R6iGT+VGT+VD(i
GT).

Figures 2 to 4 show V0>ED+R6iGT+ VGT+
In the case of VD3 (iGT) (Figure 2) 5V0=EDf
In the case of R6iGT+VGT+VD3 (iGT) (Figure 3), V0<ED-f-R6iGTfVGT+VD3(I
GT) (Fig. 4). In Fig. 2, A is the output voltage of the operational amplifier 0P, C is the current flowing through the gate circuit of the switching element SCR, and C is the output voltage of the rectifier circuit 2. Each waveform is shown, and in FIGS. 3 and 4, ``A'' represents the waveform of the output voltage of the rectifier circuit 2, and ``A'' represents the waveform of the current flowing through the gate circuit of the switching element SCR.

However, in the example circuit of FIG. 1, if the output voltage VIN of the rectifier circuit 2 under no load in FIG. 2 is about to change as shown by the broken line in FIG. As shown in the figure, the gate current flows, triggers the thyristor SCR, and the charging current of the battery to be charged 3 begins to flow.As the charging current flows in this way, the step-down transformer T of the step-down circuit 1 A voltage drop occurs due to internal impedance, and the actual output current of the rectifier circuit 2 becomes as shown in FIG. After this, when the point c is reached, the operational amplifier becomes 0.
The output voltage V of P. The above operation is repeated for every half cycle while the condition shown in FIG. 2 is satisfied. Next, in the case of Fig. 3, the point b and point c match, and in this case as well, the gate current flows through the switching element SCR, so that the battery 3 to be charged is not charged for every half cycle of the commercial power supply. It is done. After this, as the charging progresses further and the voltage of the battery 3 increases, the conditions shown in FIG. After a half cycle in which such charging is not performed, the battery voltage ED slightly decreases, and the conditions shown in Figure 3 or Figure 2 are met again, and only half a cycle occurs. Charging is performed, and as a result of this charging, the battery voltage ED rises, and the conditions shown in FIG. 4 are met again and again, and the operation of not performing charging is repeated.
The ratio of non-charging half-cycles to charging half-cycles gradually increases, and the average charge current decreases. By the way, in the case of the charger configuration as described above, the charge display circuit r is configured such that when a charging current is flowing through the battery 3 to be charged, the output voltage of the rectifier circuit 2 becomes large due to the voltage drop due to the internal impedance of the step-down circuit 2. This is detected by the Zener diode ZD and the switching element Tr is turned off.
The light emitting display element LED made of a light emitting diode is turned on during the off period.

Therefore, in the case of the conditions shown in FIGS. 2 and 3, this charging display circuit 7 visually lights up almost continuously to indicate that charging is in progress, and under the conditions shown in FIG. 4, it blinks gradually. It will blink at longer intervals (light-off time) to indicate that charging is complete. Does the present invention apply to a charger configured as described above? In the series circuit between the switching element and the battery to be charged,
A parallel circuit of another switching element and a light emitting display element is connected in parallel, and the other switching element is turned on and off depending on the magnitude of the voltage drop due to the impedance of the charging current circuit, so the voltage of the battery to be charged can be controlled. There is no need to detect or use a detection means combined with the control means of the charging circuit section, and it is possible to easily control another switching element by simply using an element that can detect the voltage drop in the circuit. This has the effect of simplifying the configuration, and since it can respond to the flow of charging current, the light-emitting display element can be turned on (turned off) continuously during continuous charging, and vice versa. During subsequent intermittent charging, intermittent lighting can be performed without using a special flicker circuit, and the effect is that the charging completion stage can be easily recognized visually.

In addition, since the switching element for controlling the light emitting display element is turned on and off via the CR integration circuit, pulse noise is removed by the CR integration circuit, resulting in the elimination of erroneous display. Since the diode is provided, the charge in the capacitor of the CR integration circuit that is once charged is prevented from being discharged to the input side, and once the switching element for controlling the light emitting display element is turned on, it remains on for a while. In particular, this has the effect of making the brightness and darkness clear during intermittent lighting of the light emitting display element. In other words, in the present application, when charging is completed when the charging current control switching element is intermittently turned on and off, the light emitting display element is intermittently turned on in response to the intermittently turned on and off to notify the completion of charging. If the light-emitting display element turns on and off at too fast a cycle (for example, every half cycle of the commercial power supply), it may be difficult to confirm that the light-emitting display element is blinking. By lengthening the time period during which the light-emitting display element is turned off when it is turned on, brightness and darkness can be clearly recognized.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a waveform diagram for explaining the charging operation, FIG. 3 is a battery to be charged, SCR is a switching element, Tr is another switching element, LED is a light emitting display element, ZD is a Zener diode, D2 is a diode, R1 is a resistor, and C is a capacitor.

Claims (1)

[Claims] 1. In a charger that flows a charging current to a battery to be charged via a switching element and controls the switching element according to the battery voltage of the battery to be charged, a separate circuit is installed in the series circuit between the switching element and the battery to be charged. A parallel circuit of a switching element and a light emitting display element is connected in parallel, and the voltage across the series circuit is detected via a Zener diode and a reverse current blocking diode to detect whether the voltage across the series circuit is equal to or higher than a predetermined voltage. , and the other switching element is turned on and off by the output of the CR integration circuit.