JPS598792B2 - 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 diode D3 is inserted and connected in the forward direction between the collector and the collector resistor R4, and a charging current is supplied from the rectified power supply output to the battery B via the charging diode D2, and the rectified power supply side end of this charging diode D2 is connected. The battery checker is characterized in that a resistor R1o is inserted and connected between the transistor Q1 and the collector of the first stage transistor Q1, and its purpose is to keep the power consumption of the circuit constant and charge the battery. To provide a battery checker that is simplified, improved in performance, and improved in reliability regarding the bleeder circuit function for keeping the current constant regardless of the 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. As a method for determining the quality of battery B, a method of detecting the voltage of battery B is generally widely used because it is simple and reliable. That is, battery B
When the voltage drops from the standard voltage to the detection level due to deterioration of the battery, the light emitting element displays this and indicates that battery B is defective. Also, if battery B is not connected to the charging circuit, the same display will be displayed.
It shows the abnormality in the part. Battery B during regular inspection
When checking the quality of battery B, the emergency light is turned on for a specified period of time, and if the display is activated during that time, it can be seen at a glance 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 display must be turned off at the inspector's will after all checks have been completed, and in that case, it must be possible to reset the display 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. In case of further resetting, it is necessary to apply a voltage of this high reset level. Figures 2 and 3 show cases in which battery B is normal and battery B in the above-mentioned battery checker, respectively.
indicates the operating conditions in the case where the
In the figure, VB is the battery B voltage, Rs is the beam set signal, and Ll is
, L2 are the set detection voltage level and reset detection voltage level of the Schmitt trigger circuit A, respectively, and the time T.

is the discharge start time, t1 is the specified time elapsed time, T2 is the commercial power supply return time, and T3 is the reset operation time. Therefore, as shown in FIG. 2, when the battery B is normal, even if the display starts at time T4 beyond the specified time t1,
After the commercial power supply is restored at time T2 and the battery B voltage VB is sufficiently restored, the display disappears when the set signal Rs is applied and set at time T3. - As shown in Fig. 3, if the battery B is defective, the display starts at time T4' within the specified time, and even if the commercial power is restored at the same time at time t1 after the specified time has elapsed, the battery B voltage B is still sufficient. If it does not recover,
The reset signal Rs is given at time T3 and the reset signal is set! At time T3' when the signal Rs becomes lower than the detection level L1, the display is re-displayed, and the display does not disappear after all. Figure 4 shows a circuit diagram of a conventional battery checker.
In this circuit shown in Figure 4, R1 is a charging resistor, ST is a rectifying bridge, B is a battery, and S is a relay! Contact, D1 is diode for setting, C1 is capacitor for reset, L
ED is a light emitting diode, and A shown within the dashed line is
This is a Schmitt trigger circuit. First, the operation of Schmitt trigger circuit A will be explained below. The first and second stage transistors Ql and Q in the Schmitt trigger circuit A
2 is in a state where Q1 is cut off and Q2 is saturated, respectively, as shown in Figure 5. , from the state shown in FIG. 5, the input voltage Vl increases, Q1 reaches saturation, and Q2 becomes a set voltage at the instant when it goes to cutoff. The input voltage at this time is assumed to be 1E. Also, from Fig. 5, the emitter potential VE of transistor Q1 is as follows: The input voltage 1E that saturates transistor Q1 is V
Equal to BE(Sat) plus 1.

Next, when the first and second stage transistors Ql and Q2 are in the Q1 saturated state and the Q2 cutoff state, respectively, the situation is as shown in FIG. From this state shown in Fig. 6, the input voltage Vi decreases and Q is cut off.
The voltage at the moment when Q2 shifts to saturation becomes the operating voltage, and the input voltage at this time is 0E. Thus, from the circuit of FIG. 6, we can obtain. Therefore, from equation 2,
By substituting this into equation 1, the following two equations are obtained as approximate equations.

When using a Schmitt circuit as a battery checker, hysteresis characteristics of about 0.8/cell for 0E and 3V/cell for (+)E are required.

This is because, if the emergency lighting is turned on and the battery voltage drops and the display is displayed, it is necessary for the battery checker's function to continue displaying the display even if the commercial power supply AC is restored, unless the resetting operation is performed as described above. According to the above equation 3,
When determining 0E and 1E in 4, the resistances R4 and R5 are the design points. These resistors R4 and R5 are R4》R5
In this case, when Q1 conducts, the currents C1 and Q2 are
When conducts, the current 1c is I. >)>Ic, the current consumption of the battery checker circuit varies greatly depending on whether or not there is a display. If the commercial power supply AC is restored while the display is currently displayed, the charging current of battery B will be consumed for the display unless the circuit is reset.
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, batteries for emergency lights and guide lights are fully charged within a specified time, and furthermore, they are toggled charged at a charging current (Xgl/30C) that does not affect the lifespan of battery B.

Therefore, if the actual charging current is less than this charging current, charging cannot be completed within the specified time, so the emergency lighting time in an emergency is shortened. Moreover, if the actual charging current is larger than this charging current, overcharging will occur, which will shorten the life of battery B. As mentioned above, when a battery checker for voltage detection and display is added to battery B for display, this battery checker circuit consumes power, and this power is approximately 20mA (1/60C). Since it is supplied from both ends of battery B, if the above display operation is performed during charging, the charging current of battery B will be reduced, which will delay the recovery of battery capacity. 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, -C+- There was a problem in that the charging current of C-1C was 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 even if a display is displayed. This is the conventional circuit shown in FIG. The circuit shown in FIG. 7 is the conventional circuit shown in FIG. 4, with the addition of a bleeder circuit
When Q1 is conductive, Q3 is also conductive and the current is 1. is applied, and the current 1D is cut off during display operation when transistor Q2 is conductive.In this case, by selecting 1c+ID, the battery checker circuit always has Ic+
The mechanism is such that a current flows through IO-1 and the charging current of battery B is kept constant regardless of the display 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 I had a problem with getting high. In addition, the conventional circuit shown in Fig. 8 uses a switching relay contact S to turn on the bamboo bleeder circuit X during charging, and when the light emitting diode LED provided as a display element is not lit, the display current is By supplying the same amount of current to the bleeder circuit This is what I did. However, this conventional circuit also has the same problems as the conventional circuit shown in FIG. 7, such as an increase in the number of parts and an increase in cost. 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 diodes D2 and D3 to the conventional circuit shown in FIG. In addition, in the above-mentioned formulas 3 and 4, R4
〉R5 and RlOmiR5.

Therefore, in the circuit of the embodiment shown in FIG. 1, when the commercial power AC unit is cut off and the voltage of battery B is higher than the detection level, Q1 is conductive, Q2 is cut off, and the LED does not emit light. At this time, current 1c flows through Q1 via R4. When the voltage drops below the detection level, Q1 is cut off and Q2 is turned on, turning on the JLED. In this case, the current 1c is the current value that causes the LED to emit light, and R4
>Ic is established due to the relationship of R5, which means that the current consumption of the battery checker circuit is very small until the LED is turned on. Also, since R4>R5, the above 3,
From equation 4, a sufficient hysteresis voltage can be obtained.
Next, when commercial power is restored, when Q1 becomes conductive, Rl
A current approximately equal to Ic minus Icl2-2 flows through O, and the current when Q2 is conductive (LED lighting current)
is almost equal to

In other words, the current consumption of the battery charger circuit can be kept almost constant regardless of whether the LED is lit or not, and this means that the battery B charging current can be kept constant regardless of the battery charger circuit. . Therefore, if a charging circuit is designed so that the sum of the current consumption of the battery checker and the specified charging current of battery B can be obtained, battery B can always be charged with the specified charging current. As described above, in the present invention, a diode is inserted and connected in the forward direction between the collector of the first stage transistor of the Schmitt trigger circuit and the collector resistor, and charging current is supplied to the battery from the rectified power supply output through the charging diode. Since a resistor is inserted and connected between the rectified power supply side end of this charging diode and the collector of the first stage transistor, the power consumed as a battery checker during charging is independent of whether it is displayed or not. In addition, in the case of emergency lighting, the power consumption of the detection circuit portion is equal to the lighting current of the display element, making it possible to effectively utilize the battery. It is possible to provide sufficient hysteresis to the circuit, and there is no need to provide a separate bleeder circuit, which simplifies the circuit configuration, reduces the number of parts, reduces costs, and improves reliability. have

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of an embodiment of the present invention, Fig. 2 is an explanatory diagram of the operation of a general battery checker when the battery is normal, and Fig. 3 is an explanatory diagram of the operation of the same battery checker when the battery is defective.
Fig. 4 is a circuit diagram of a conventional example, Figs. 5 and 6 are explanatory diagrams of the operation of the Schmitt trigger circuit, Fig. 7 is a circuit diagram of another conventional example, and Fig. 8 is a circuit diagram of yet another conventional example. A is a Schmitt trigger circuit, B is a battery, D2 and D3 are diodes, LED is a light emitting diode, Ql and Q2 are transistors, and RlO is a resistor.

Claims (1)

[Claims] 1. In a battery checker that detects battery voltage with a Schmitt trigger circuit and drives a display element such as a lighting diode, a diode is inserted and connected in the forward direction between the collector of the first stage transistor of the Schmitt trigger circuit and the collector resistor. At the same time, a charging current is supplied to the battery from the rectified power supply output via a charging diode, and a resistor is inserted and connected between the rectified power supply side end of the charging diode and the collector of the first stage transistor. A battery checker characterized by: