JPS5960368A - Control circuit for emergency lamp - Google Patents

Abstract

PURPOSE:To improve temperature characteristic, to realize small-sized, high- compact packaging, and to reduce the cost by using a differential amplifier composed of two transistors (TR) and a hysteresis circuit for constitute a control circuit which is used for the voltage monitoring circuit of a storage battery as an emergency lamp power source. CONSTITUTION:A reference voltage VRef is applied to the base of a TRQ2 of the differential amplifier 1 and a voltage VIN to be compared is applied to the base of the other TRQ1 after being divided by resistances R5 and R6. When the base potential of the TRQ1 is lower than that of the TRQ2, the TRQ2 turns on to turn on TRQ4, and the TRQ3 of the hysteresis circuit 2 turns on to put a resistance R4 in parallel to the resistance R6, so that the voltage applied to the base of the TRQ1 drops. When the base voltage of the Q1 rises above that of the Q2 to invert the differential amplifier 1, the base voltage of the Q1 rises more than when the resistance R4 is interposed to the same input voltage VIN. when the input voltage VIN drops, the differential amplifier 1 is not inverted unless the voltage drops below the level in the rising. The inverted voltage of the differential amplifier 1 is used for turn on and off a display element to constitute the voltage monitoring circuit.

Description

[Detailed Description of the Invention] Unknown The control circuit for the emergency lights of the present invention, more specifically, monitors the voltage status of the storage battery used as the emergency light power source, and issues an alarm when the Gotun Pond becomes abnormal. The present invention relates to a control circuit used in a voltage monitoring circuit.

Emergency lights are normally powered by commercial power, and in the event of a power outage, they automatically switch to a built-in storage battery and turn on in an emergency. Since the same lamp is turned on both when hunting and during emergencies, parts with relatively short lifespans such as lamps can be easily judged to have worn out just by looking at the normal lighting condition, and can be immediately replaced. However, the built-in storage battery (11U, Nitsu'Jru, cadmium storage battery is often used) can be turned on for a specified period of time unless it is discharged? It is not easy to determine whether t'J'tii exists. For this purpose, a storage battery voltage monitoring circuit has been developed that can simply detect the storage battery capacity and display an alarm when the voltage is low, and is known as a battery voltage monitoring circuit.

As an emergency lighting standard, consideration is given to the efficiency of discharging and charging the storage ηL battery after redundant charging, which is considered to be effective lighting for a specified period of time after redundant charging and maintaining a constant brightness. 1
As shown in the figure. When the storage battery is normal, it will be as shown in A, and the specified amount is 1 and the specified 'i1 [on the tool]. Since the specified voltage is about 0.9V per cell, it is 5.4V for 6 cells. On the other hand, a storage battery that is defective or at the end of its life has a discharge characteristic as shown in B, and the voltage at the specified time of open 'r is the specified 'i1. The pressure reaches below or almost zero. On the other hand, even if a storage battery is defective or at the end of its lifespan, the 71i voltage is approximately the same voltage as a normal storage battery (generally about 1.6V), even if the battery is defective or at the end of its lifespan. /cell, so it recovers to ?'Lt 9.6 V) at 6t. Therefore, a storage battery monitoring device was developed that monitors the storage battery voltage after the emergency lighting has been turned on for a certain period of time, and issues some kind of notification if the voltage is below a specified voltage. For example, when the voltage is 6 tons, the device will issue an alarm at 52 to 5.4V or less. In addition, even if the storage battery is defective due to its charge/discharge characteristics or is at the end of its lifespan, the voltage will recover during charging, so the circuit system has so-called 2% hysteresis, which maintains the detection state even if the voltage increases. FIG. 2 shows a conventional storage battery voltage control circuit as described above, which is used in a visual device, and this circuit is connected to a resistor R7. , R3 determines the steresis, the value of which is denoted by . ``Indicated by a set'': As shown, this threshold F' voltage includes the VBE of the transistor, and when the temperature changes, this '[1L pressure value changes.

The temperature coefficient of VBE is approximately -2 mv/'O and 5
A change of 0'C causes a change of 0.1■, which is not desirable. In length,
Conventional emergency light ff1lJ control circuits use chip components for high-density mounting in order to achieve miniaturization, but chip components are inherently discrete, and the design takes into account variations in individual components. However, there are many factors that increase the cost depending on the rank of the component, and even if chips are mounted, the volume cannot be reduced to a certain level, and the size of the container, g l
It had the disadvantage that there were restrictions on the size of the equipment when it was included.

The present invention has been made in consideration of this point, and its objective is to improve the temperature IF resistance and improve the temperature IF resistance of the L roller.
It enables compact and high-density mounting, and has a large +1
Another objective is to achieve sharp switching characteristics, and another objective is to make it easier to convert into l-chip ICs. It is in. The present invention will be explained in detail below with reference to Examples.

In FIG. 8, (1) is a differential amplifier, which is formed by transistors Q1, Q2, and resistors R1, R2, and R3. f2) /rJ: A systeresis circuit, formed by a transistor Q, an I resistance R,,1<6, (3)
is an output circuit formed by a transistor Q4% and resistors R2 and R8.

Now, one transistor of the differential amplifier +1). 2, the reference voltage VRef is applied to the base of the other transistor Q
1 base (the voltage VIN to be compared is connected to the resistor R,,■
A voltage divided by <6 is applied. If the base level of transistor Q1 is lower than the base level of Q2, Q2 turns on, transistors 1 to 4 turn on, and a current flows through resistors R7 and R8.
1L pressure is generated, 7 resistors are turned 1, and resistance R
.

is connected in parallel with resistor R6, and the combined resistance is I(6
lower than that of a single unit. Therefore, the voltage applied to the base of the transistor is I. Therefore, the base of transistor QI 11. , the pressure rises above the pace' voltage of Q2, and the difference "-ψ" (+lj+1) is reversed, the l-transistor Q is turned off, and (
Since the base of 43 is grounded, it is turned off, and the resistor R, is separated from I<6, and the base of transistor Q1 ↑)
], the voltage increases compared to when the resistor P was included for the same input voltage VIN. Therefore, when the input voltage VIN falls, the input 11i, LfVxN becomes lower than when it rises...7 voltage) and the running increaser 1↑J unit (+) does not invert. When this is graphed, it becomes as shown in Fig. 4. In Fig. 4, the lower voltage is expressed as the display element on-voltage (
5, 2v), and if the higher tlf If is the display element off voltage (9, 6■), then II'i, the pressure monitoring circuit is tj
I can do 4 things.

A simulation was performed using the circuit shown in Figure 58 with the following constants.

R+ "R, -2 2K Ω, Rs"
IKΩ, R,=8KΩ, I<5
-10KΩ, R,:3KΩ,R,=+
<,=5K Ω, (J+ "CJ2"
Q, = E11, Q, = E28A The result is as shown in Fig. 5, and the change at the time of switching is slow. That is, since the circuit response at two threshold voltages is slow, for example, when the input voltage VIN gradually decreases,
5. From 8■5. The circuit is gradually inverted towards OV. In such a state, if the voltage is about 5.4V, the state of the circuit becomes unstable, which is not good for welfare. Therefore, it is necessary to devise a way to make this switching every time. This phenomenon of poor switching occurs due to poor switching of the transistor CJ3 from on to off.The cause is that the resistances R, R2 are small, and the on/off characteristics of the transistor Q4 are deteriorated. Transistor 92. The base current is small and the collector current does not flow sufficiently, resulting in deterioration of on/off characteristics.

Fig. 6 shows another embodiment of the present invention, which solves the above-mentioned problems in the embodiment of Fig. 3.
Transistors Q5 and Q6 form an active load and the difference! lI
A steresis circuit (2) is used as a load for the amplifier (1), and is composed of a parallel circuit of a transistor (1) and a resistor (1). Therefore, when the transistor Q is turned on, the resistance becomes 4.
When the transistor Q1 is completely short-circuited, the pace voltage ratio VB of the transistor Q1 is l.

Vn　ξ−−−□・　VIN Rs+r<.

When transistor Q3 is off and resistor 1<, is inserted, R4+R5+RR. - power, turn on and off this transistor by 1l
The signal that can be controlled is the output circuit (3) and the differential amplifier r
In device 9 (1), transistor Q2 is on, i.e.
When VRef)VB, transistor Q4 turns on,
When the transistor Q7 is turned on, the transistor (J3) is turned on. The temperature coefficient of VBE can be canceled out.

The steresis characteristic is 1-transistor CI! when l-transistor Q is 1. Since the base voltage of + is lower than when transistor Q3 is off, resistor 1<4, so that the base voltage of transistor QI when input voltage VIN rises is higher than when input voltage VIN falls.
It is obtained by selecting R5 and R6 by Jx.

A simulation was performed using the circuit shown in FIG. 6 with the following constants.

R* = I K Ω, R1 = 8Ω,
Ra ” 18 K Ω, R, = 2.4 Ω
, R, = 5 to Ω, QI” Qz = (J7 = E
11, QI = Qs = Q6 = E28A, Q3 = E
12 As shown in Figure 7, the results show a 12-shape transition characteristic (±
The results showed that (within 0.1v). Further, the threshold voltage +f: 52V (lower limit) and 9.6V (upper limit) were obtained. However, it has been found that there are some problems with the embodiment shown in FIG. 6.

It is L transistor Q3 which bypasses resistor l<4.
Since the transistors Q3 and QI form a current mirror, the current that has flowed into the resistor Q7 is drawn into the collector of the transistor Q1 for 1 minute, which causes the current to flow into the resistor R5,1. This is based on the idea that all the current flowing through the transistor Q3 is drawn into the power of the transistor Q3, thereby bypassing the resistor R4.

However, when this circuit is integrated into an IC, the following problems arise. That is, the PNP transistor Q4 is a normal I
Cpu01! The transistor is a lateral PNP transistor, and the hFE characteristic for the collector 1 ( ) 7 current has a problem in that hpa rapidly decreases as the collector current increases. Of course, particle P N P l-
There is also a process that can make L-th transistor,
As the number of processing increases, Pro-7 is required to be re-requested multiple times, resulting in high costs. There is also the idea that IAE can be performed by using multiple lateral PNP I-transistors to increase the rector current, but since IIFE is originally smaller than that of the PNP-I transistor, the base current increases and the active current increases. The burden will be placed on the load Q6, resulting in unstable circuit operation. Further, increasing the open area of the P N P I-transistor is not preferable because it also leads to an increase in the chip area.

Figure 58 shows another embodiment of the present invention, which solves the problems described in the embodiment shown in Figure 6, in which an active load is configured with PNP transistors Qs, Q, and l. Differential amplifier (
3). The input voltage VIN is divided by resistors R1, R, and R6, and the voltage at the intersection of resistors R6 and R is supplied to the base of the transistor Q. Transistor Q2
A reference voltage Vii6f is input to the base of . The output is taken out by the transistor Q4 from the connection point between the collectors of the transistors Q2 and Q6, and the output is taken out by the transistor Q8.
Take out the output using the Mitsuta follower. transistorro 3
A transistor forming the steresis circuit (2),
When the output is at the I] level, the resistor R is shorted. The transistor Q2 is used to cancel the temperature coefficient between the base and the base of the transistor Q3. -Here, a stabilized power supply is used for the reference voltage Ref. There are many well-known stabilized power supply circuits that are stable with respect to temperature and input voltage, and these are used.

Now, the base voltage of the 7 transistor Ql or the transistor Q
Base 'r of 2: When lower than the voltage, the transistor Q
+ off, Q2 turns on, so transistor Q turns on,
When the transistor 08 is on, the transistor Q3 is on, and the resistor 1<4 is bypassed by the transistor (J3. Therefore, the base voltage VBH at which the transistor 08 is inverted is equal to the Vca of the transistor Q3. (
sat), it is shown as . - When it is reversed, transistor Q3 turns off and resistor 1 decreases. is inserted into the circuit, so the inversion voltage VBt is as follows. According to this example, Tora, , 7 Jista (, J4
The output of is buffered one stage by a transistor,
Since the output is also fed to the emitter follower of the transistor Q8, there are no problems caused by the embodiment of FIG. 6, and the embodiment can operate satisfactorily. As an example of operation, R,=3KΩ, R,=18Ω, R6=
When VBH% VBL was experimentally determined using Ω at 2°4 and Vuef=1.2V, VBH=9.7V (calculated value 10.2V)Vnt,
= 5.2 V (fJ calculation value 5.2 V).

As described above, the present invention applies a base voltage of 1 s to one input of a differential amplifier [1] formed by two transistors, and applies a voltage to be compared obtained from an emergency lighting storage battery to the other input. is applied after being divided by a resistor, connected to the collector full output circuit of the transistor to which the reference voltage of the differential amplifier was applied, and connected to the other input circuit of the differential amplifier. 1. Since the output circuit described in 1 is connected, temperature characteristics can be studied, it is possible to use a single chip IC, compact and high-density packaging is possible, and a large cost reduction can be achieved.
Connect an active load to the iJ device, and short-circuit the voltage dividing resistor using a transistor in the steresis circuit.
It is possible to restore the sharp cutting characteristics, operate stably, and connect the output 1[4i path with a 13-inverter circuit, making it easier to convert into chip ICs. 0 that has all the effects

[Brief explanation of the drawings] Figure 51. Figure 2 is a circuit diagram of a conventional Ni control circuit. Fig. 3 shows circuit 1s1 of one example of M11 according to the present invention, Fig. 4 shows characteristic 4 of the same example, Fig. A circuit diagram of another example of "misfire",
Figure 7 is based on the experimental results. Figure 8 is a circuit diagram of another embodiment. fl+-differential excitation booster + lJ device, (2) steresis circuit,
(3)... Output circuit, Q3, Q2, Q,... Transistor, R6, r<,... Voltage dividing resistor, Vnef...
Reference voltage, VIN...input'! J, Pressure, Su5, Q6・
・Transistor s Qs as Nomushi υi'L 'm
...A transistor that forms an emitter follower. Agent Patent Attorney Ishi LIJ Chief 7ll Figure t! 3 Figure Shin 4 Figure Q3 Off Q3 On Male 5 [4 Figure 6 @57 Figure 5.2V 9.6V V
IN Procedure Amendment (Home) April 1981 411 Commissioner of the Patent Office 1, Indication of case + 1U sum 57? 4ffrl'dffi 171941
Q2. Name of originator Relation to emergency lighting control circuit 3, supplementary i, lE case Patent applicant address Address 1048 Kadoma, Kadoma City, Jinhanfu M
i (583) Matsushita Electric Works Co., Ltd. Representative Iku Kobayashi 4, agent postal code 530 5, date of amendment order 7, subject of amendment as per the attached sheet IE Application number Patent application 171941-1 , Sueyori 1
．． l'] In the second line of Hosoichi's convex shell, delete "Term" as "1 stipulation".
I will do E. 2. Delete the entire sentence on page 7, line 7 of the same page, and insert the following length. "Qs (NPN for small grades) 5-/, ;s5), Q4(
Small (ffi “J for PNPh57/,;S51) J3
゜ The entire text of lines 15 to 10 of Tribute No. 9 above is deleted by 11, and the entire text of F is inserted.

Claims (1)

[Claims] (1) A reference voltage is applied to one input of a differential amplifier formed by two transistors, and a voltage to be compared obtained from the emergency light storage battery voltage is applied to the other input of the differential amplifier. The collector of the transistor to which the reference voltage of the differential amplifier was applied was connected to the output circuit, connected to the other input circuit of the differential amplifier, and the voltage was applied to the input of the steresis circuit. An emergency light control circuit that consists of connecting an output circuit. (2) Control of emergency lighting according to claim 1, characterized in that an active load is connected to the differential amplifier, and the steresis circuit is configured to short-circuit the voltage dividing resistor using a transistor. circuit. (8) An emergency light control circuit according to claim 1 or 2, characterized in that the output circuit is connected to an ivy power D circuit.