JPS598791B2 - Bad Teri Chietska - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a battery checker in which battery B voltage is detected by a Schmitt trigger circuit A to drive a display element such as a light emitting diode LED. A series circuit consisting of a resistor R1o and a switch element that becomes conductive when the first stage transistor Q1 is conductive is added between the collector and the battery B, and the first stage transistor Q1 is Relating to a battery checker comprising a collector connected to the base of a second stage transistor Q2,
The purpose is to keep the power consumption of the circuit constant,
To provide a battery checker which is simplified, improved in performance, and improved in reliability regarding a bleeder circuit for keeping battery charging current constant regardless of display.

Generally, a battery checker is a display device for determining whether a battery B used for emergency lights or guide lights is normal or deteriorated.

Battery B
This method of detecting voltage is simple and reliable, so it is widely used. That is, when the voltage of battery B drops from the standard voltage to the detection level due to deterioration of battery B, an indication is provided by the light emitting element to indicate that battery B is defective. Further, even when battery B is not connected to the photoelectric circuit, a display is made to indicate an abnormality in the battery B portion.
When checking the quality of battery B during periodic inspection, the emergency lighting is turned on for a fixed period of time, and if the display is activated during that period, it is immediately clear that battery B has deteriorated. In this case, if there are multiple appliances, it is difficult to check the above at the same time when the specified time has elapsed, so the commercial power is restored immediately after the specified time, and the information displayed at that time is requires a function that continues to display even if the voltage is restored. In other words, the function of the battery checker is to display at a detection level (lower than the standard voltage), but once the display is displayed, it must not disappear even if the voltage exceeds the detection level. The checker must be able to turn off the OFF display at his/her will after all checks have been completed, and in that case, it must be possible to reset it only when the battery B voltage has sufficiently recovered.
Therefore, for the function of the battery checker, it is necessary to have a hysteresis effect between the detection level and the reset level, and the reset level must be higher than the standard voltage or the maximum charging voltage of battery B. t
When performing a reset, it is necessary to apply a voltage at this high reset level.

Figures 3 and 4 show the operating condition when the battery B is normal, when the battery B is defective, and when the battery B is defective. B voltage, RS beam set signal, L,,L
2 are the detection voltage level and reset detection voltage level of the Schmitt trigger circuit A, respectively, and the time T. is the discharge start time, T
, is the elapsed time of the fixed period, T, is the commercial power return time, T,
is the reset/discharge operation time.

Therefore, as shown in Fig. 3, when battery B is normal, even if the display starts at time T, exceeding the specified time T, the commercial power supply is restored at time T, and the battery B voltage V.
After B has recovered, the display disappears if the reset signal RS is applied and set at time T36. As shown in Figure 4, if battery B is defective, it will be returned at time 1 within the specified time.
If the battery B voltage VB does not recover sufficiently even if the music power is restored at the same time as the prescribed time elapses at the time T, t, the battery B voltage VB is not recovered sufficiently by applying the reset signal RS at time T3l. At time t'3 when RS has fallen below the detection level L, the display is re-displayed, and the display does not disappear after all. Fig. 5 shows a circuit diagram of a conventional battery checker. In this Fig. 5 circuit, R is a charging resistor, ST is a rectifying bridge, B is a battery, S is a relay contact D, a diode for beam setting, and C is a beam setting diode. capacitor, L
ED is a light emitting diode, and A shown within the dashed line is
First, the operation of the limit trigger circuit A, which is a limit trigger circuit, will be explained in detail below.

In the Schmitt trigger circuit A, when the first and second stage transistors Q, , Q, are in the saturated state, Q1 is cut off, Q is as shown in FIG. As the input voltage Vi increases from the state shown in Fig. 6, the voltage at the instant when Q, reaches saturation and Q, goes to cut-off becomes the set voltage, and the input voltage at this time is expressed as (1)E. shall be. Also, from Fig. 6, the emitter potential VE of the transistor Q is as follows: The voltage 0E that saturates the transistor Q1 is VE and VBE.
The value of (Sat) 1 is equal to 1.

Next, when the first and second stage transistors Q, , Q, are in the saturation state and the cutoff state, the situation is as shown in FIG. From this state shown in Fig. 1, the input voltage Vi decreases and Q is cut off.
The voltage at the moment when the voltage Q is transferred to the current voltage becomes the operating voltage, and the input voltage at this time is 0E. Thus, from the circuit of FIG. 1, it is possible to obtain. Therefore, by substituting this for the [phase] equation from the [existence] equation, we obtain the following two equations as approximate equations.

If a Schmitt circuit is used as a battery checker, hysteresis characteristics of about 08 V/cell for EE and 3 V/cell for 0E are required.

This is because, when the battery voltage drops due to emergency lighting, the battery checker function is required to continue displaying the display even if the commercial power supply AC is restored, unless the reset operation is performed as described above. Therefore, when determining 0E and 0E in the above equation 0 and [phase], the resistances R4 and R5 are the design points. A sufficient hysteresis effect can be obtained by setting the resistors R4 and R5 to R4>>R5, but in this case, when Q1 conducts, the currents 1C1 and Q2
The current 1C2 when the battery is turned on becomes IC2》ICl, and the current consumption of the battery checker circuit varies greatly depending on whether or not there is a display. Commercial power AC in the hidden state that is currently displayed
If the reset operation is not performed when the power is restored, the photoelectric current of battery B will be consumed for display.
There was an undesirable problem in that it was not possible to obtain a constant charging current as it was significantly different from the charging current when the battery was reset, which affected the reliability and life of the battery B. That is, in general, the emergency light guide light battery 1 is fully charged within a specified time, and furthermore, it is toggled charged at a charging current (approximately 1/3 C) that does not affect the life of the battery B.

If the charging current is less than this, charging cannot be completed within the specified time, so the emergency lighting time in an emergency is shortened. Moreover, if the charging current is higher than this, overcharging will occur and the life of battery B will be shortened. Therefore, when a battery checker for voltage detection and display is added to battery B for display as described in E, this battery checker circuit will consume power, and this power is approximately 20 mA (1/6
0C) and is supplied from both ends of battery B, so if the above display operation is performed during charging, the charging current of battery B will be reduced and recovery of battery capacity will be delayed. Therefore, in order to prevent this, if the charging circuit is designed so that the normal charging current flows when the battery checker circuit is displaying, then if there is no display during charging, the T- 0C
A problem arises in that a charging current of +both C=ΣNC is supplied to battery B, causing battery B to be overcharged and shortening its life. Therefore, when a battery checker is added to battery B, it is necessary to always keep the current consumption of the battery checker constant so that the charging current does not change depending on whether the display is displayed or not. What is provided is the conventional circuit shown in FIG.

The circuit shown in Fig. 8 is the conventional circuit shown in Fig. 5 with the addition of a bleeder circuit X composed of a transistor Q3, resistors Rll, Rl2, Zener diode ZDl, diode D3, and capacitor C4, so that when transistor Q1 is conductive, Q3 is also conductive. The current 1D is caused to flow through the battery checker circuit, and the current 1D is cut off during the display operation when the transistor Q2 is conductive.In this case, by selecting 1C2+ID, a current of 1C2+ID=I is always caused to flow through the battery checker circuit and the display is performed. The configuration is such that the charging current of battery B is kept constant regardless of the operation. However, in such a conventional circuit, although it is possible to keep the charging current of battery B approximately constant, on the other hand, the bleeder circuit There was a problem with high costs.
The present invention has been provided in view of the above points, and one embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a circuit according to an embodiment of the present invention, which is constructed by adding a resistor RlO and a diode D2 as a switch element to the conventional circuit shown in FIG. 5, and in equations 3 and 4, R4; Therefore, it is designated as ICl; IC2.

Also, R4》RlO. Therefore, the transistor Ql,
When any of Q2 is conductive, the current consumption of the battery checker circuit is constant, and therefore it is possible to eliminate fluctuations in the charging current depending on whether a display is displayed or not. Next, the operation of the circuit shown in FIG. 1 will be explained.

Now by setting R4;R5, 0E;1 from formula 3,4
E, and if this continues, the hysteris effect will not be obtained. Therefore, resistor RlO (》R4) and diode D
By connecting Rl to 2, when Q1 is conductive, Rl
A collector current of Q1 flows from O through D2, and when the battery voltage decreases and Q enters the cutoff region, this current becomes the base current of Q2 and brings Q2 into the conduction region. In this state, Q1 is suddenly cut off due to the voltage drop across the emitter resistor R8, and Q2 is suddenly turned on. The voltage in this case is EE, and it operates at a voltage determined by EE.

Next, when Q2 is conducting and a set voltage is applied, Q1 attempts to change from the cut-off state to the conduction state due to the reset high voltage. However, the forward direction of the diode is ON.
Because of the voltage, 1c (does not flow and the current that still flows through RlO becomes the base current of Q2 and continues to conduct Q2. When the set voltage increases further and reaches a level where a sufficient hysteresis effect can be obtained, is forced to Q1
As a result, the potential a at point a in the figure drops, and between it and the potential Vb at point b in the figure, Vb-a = VD.
ONVDON: At the point when the relationship of 0N voltage in the forward direction of D2 is established, the base current of Q2 via R and O is D
2 to the collector current of Q1 to abruptly cut off Q2, and at the same time rapidly turn on Q1 due to the effect of the emitter resistor R8.

Therefore, it is possible to obtain a hysteris effect even with R4R5, ICl and IC2, and ~CCXR
8 Is this Kamogori set voltage 1E-? -1-VI3E(
Sat) 1P - is a much higher voltage than the value of 1E given by p.

Further, FIG. 2 shows a circuit according to another practical example of the present invention, in which a combination circuit of a transistor Q4 and a Zener diode ZD2 is used as the switch element. This is added to the conventional circuit.

Therefore, in the embodiment circuit of FIG. 2, when Q1 is conductive, Q2 is cut off by the counter electromotive force of R8. Therefore, the potential at point C in the figure is high, making the Zener diode ZD2 conductive and causing the current 1C'1 to flow through the resistor RlO. In this state, when the battery voltage decreases and reaches a voltage that satisfies , Q begins to enter the cutoff region and raises the potential at point a. Then, since Q3 also tries to enter the cutoff region, IC'1 becomes the base current of Q2, and the effect of the emitter resistor R8 that pulls Q2 into the conduction region causes this operation to proceed rapidly, cutting off Q1 and making Q2 conductive. Make it. Next, when Q2 is conductive and the battery B voltage is restored and a reset voltage is applied, Q1 attempts to go from the cut-off state to the conduction state due to the high voltage of the reset pulse. However, CE(Sat) of transistor Q2
4, IC'l does not flow and the current still flowing through RlO becomes the base current of Q2 and continues to conduct Q2.
When the set voltage increases further and reaches a level where a sufficient hysteresis effect can be obtained, the potential at point a drops and the potential at point b becomes Vb and Q1 is forcibly pulled into the conduction region. During this period, a time comes when the relationship of Vb-a=VcE(Sat)4 is established. When Q1 becomes semi-conductive, I
Since Cl flows out and increases the voltage drop of R8, Q2
operates in the direction of interruption, raising the potential at point C. Thus, between the potential a at point a and the potential c at point C, b
-Va=ZD2+VBE(Sat)4 When the state is reached, Q4 becomes conductive and the Q
2) is connected to I via Q4.
C'1 will flow, causing Q2 to be abruptly cut off and Q1 to be suddenly conductive. Therefore, even if R4/R5, ICl/IC2, a hysteresis effect can be obtained, and this In this case, the set voltage is 4E.
Tomoe? ? +E(Sat)1Pj-1-P (+
) The voltage is much higher than the value of E.

As mentioned above, in the present invention, a series circuit consisting of a resistor and a switch element that conducts when the first stage transistor is conductive is added between the collector of the first stage transistor of the Schmitt trigger circuit and the battery. Since the collector of the first stage transistor is connected to the base of the second stage transistor through a switch element with reverse polarity, the power consumed as a battery checker is always constant regardless of whether there is a display or not. It is possible to provide sufficient hysteresis to the battery voltage detection operation, and there is no need to provide a separate bleeder circuit, which simplifies the circuit configuration, reduces the number of parts, reduces costs, and increases reliability. It has the effect of improving sex.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of one embodiment of the present invention, Fig. 2 is a circuit diagram of another embodiment of the same as above, Fig. 3 is an explanatory diagram of the operation of a general battery checker when the battery is normal, and Fig. 4 is a circuit diagram of the same battery checker as above. Figure 5 is a circuit diagram of a conventional example, Figures 6 and 7 are diagrams explaining the operation of a Schmitt trigger circuit, Figure 8 is a circuit diagram of another conventional example, and A is a circuit diagram of a Schmitt trigger circuit. Circuit, B is battery, RlO is resistance, L
ED is a light emitting diode, and Ql and Q2 are transistors.

Claims (1)

[Claims] 1. In a battery checker in which battery voltage is detected by a Schmitt trigger circuit to drive a display element such as a light emitting diode, a resistor and a resistor are connected between the collector of the first stage transistor of the Schmitt trigger circuit and the battery. Add a series circuit with a switch element that conducts when conductive, and connect the collector of the first stage transistor and the collector of the second stage transistor to the base of the second stage transistor through this switch element with opposite polarity. A battery checker made up of