JPS61185237A - Voltage display circuit of charging type cleaner - 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 Field of the Invention The present invention relates to a voltage display circuit for a rechargeable vacuum cleaner, which detects the voltage of the battery of the rechargeable vacuum cleaner and prevents battery consumption.

2. Description of the Related Art In a conventional voltage display circuit for a rechargeable vacuum cleaner, when a switch 1 shown in FIG. 3 is turned on, power is supplied from a battery 2 to a motor 4 via a resistor 3. A display element 6 such as a light emitting diode is lit by a voltage drop generated when the current flows through a current limiting resistor 6.

Problems to be Solved by the Invention In such conventional circuits, part of the voltage of the battery is passed through the resistor 3.
As a result, the voltage of the battery 2, which is originally low, is not 100% effectively transmitted to the motor 4, and since a large current flows through the resistor 2, heat generation also becomes a problem. Furthermore, since variations in the characteristics of the light emitting elements 6 and the resistors 6 directly affect the operation of the circuit, there are problems in that the variations in the operation become large and the operation becomes extremely unstable.

Therefore, the present invention aims to transmit the battery voltage to the motor without waste and to display a voltage drop using a stable circuit.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention divides the voltage of the battery by resistors, compares the resulting voltage with the voltage of the Zener diode using the first transistor, and uses the output to divide the voltage into the second transistor. It controls the display element connected to the transistor.

According to the above-described configuration, the present invention lights up the display element when the value obtained by dividing the voltage of the battery by resistance is higher than the value of the Zener diode, and when the value is reversed, the display element lights up from the first transistor. The current stops flowing to the second transistor, causing the display element to turn off.

EXAMPLE An example of the present invention will be described below. FIG. 1 is a circuit diagram showing an embodiment of a voltage display circuit for a rechargeable vacuum cleaner according to the present invention. In FIG. 1, 21 is a battery, 22 is a switch,
Reference numeral 23 denotes a motor, and when the switch 21 is turned on, power is supplied from the battery 21 to the motor 23, which generates suction power as a vacuum cleaner. 24.26
is a resistor that divides the voltage of the battery 21, and the divided voltage VB is the emitter terminal E1 of the first transistor 28.
It is connected to the. 26 is the first transistor 2
A current limiting resistor 27 is connected to the base of the first transistor 28, and a Zener diode 27 is connected to the base of the first transistor 28, and its voltage vZ is the reference voltage applied to the base terminal B1 of the first transistor 28. connected as. 29 is a current limiting resistor, 3o is a light emitting diode, and 31 is a second transistor. The resistor 29 and the light emitting diode 3o are connected in series to the collector terminal C2 of the second transistor 31 and the + side of the battery 21. There is a connection in between. Further, the base terminal B2 of the second transistor 31 is directly connected to the collector terminal C1 of the first transistor 28.

Here, FIG. 2 shows the relationship between the battery voltage and suction force during operation of the rechargeable vacuum cleaner. In FIG. 2, 6V indicates the voltage of the battery, and P indicates the attraction force. As can be seen from the figure, the voltage V of the battery maintains a substantially constant value up to a certain point, but as the capacity decreases, the voltage V drops rapidly. The suction force P also decreases at the same time. Continuing to discharge even when the voltage drops puts a great deal of stress on the battery, which has a major impact on its lifespan, and the vacuum cleaner's suction power is drastically reduced, so the display element should be removed at the part indicated by 32 in Figure 2. It is effective to turn off the lights.

To explain the effect using the configuration shown in Figure 1, vBE is the first
Assuming that the voltage between the base and emitter of the transistor 28 is VB+vBE1>v2 when the battery 21 still has sufficient capacity remaining and the voltage is high, the first transistor 28 is in the ON state, and the emitter-to-terminal E1
A current flows from the collector terminal C1 to the collector terminal C1, and the current flows directly to the base terminal B2 of the second transistor 31.

Then, the second transistor 31 is also turned on,
The display element 30 lights up. However, as the capacity of the electric power 21 decreases and the voltage becomes lower, V B + V B E 1 < V z, the first
Current does not flow through the transistor 28 (it becomes an OFF state), so the second transistor 31 also becomes an OFF state, and the display element 30 turns off, indicating that the battery voltage has decreased.

In the embodiment shown in FIG. 1, vZ is kept constant and the resistance 2
If 4.25 is stable, vBEl is stable, so the operation of the circuit can be stable and reliable.

Effects of the Invention As is clear from the description of the embodiments above, according to the present invention, the voltage of the battery can be transmitted to the motor without waste, and the drop in battery voltage can be reliably displayed within a stable range. This has great effects, such as preventing the battery from being used unnecessarily and protecting the battery.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a voltage display circuit of a rechargeable vacuum cleaner according to an embodiment of the present invention, Fig. 2 is a graph showing the relationship between battery voltage and suction force, and Fig. 3 is a conventional example 7. FIG. 2 is a circuit diagram of a voltage display circuit of a rechargeable vacuum cleaner. 21...Battery, 23...Motor, 24,
25... Resistor for voltage division, 27... Zener diode, 28... First transistor,
3o... Light emitting diode, 31... Second
transistor.

Claims (2)

[Claims] (1) The voltage of the battery is divided by resistance, the resulting voltage is compared with a reference voltage by a Zener diode, and the collector terminal of the first transistor is directly connected to the base terminal of the second transistor. A voltage display circuit for a rechargeable vacuum cleaner in which a display element is connected between the collector terminal of the second transistor and the positive terminal of the battery. (2) A display element that turns off when the battery is fully charged and a display element that turns off when the battery voltage drops.
A voltage display circuit for a rechargeable vacuum cleaner according to claim 1, which comprises the same display element.