JPS6380727A - Charge completion detector - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Before Industrial Use] The present invention relates to a charging completion detection device for detecting the completion of charging of a storage battery to be charged.

[Conventional technology]

Generally, when a storage battery such as a nickel-cadmium battery or a sealed lead-acid battery is charged with a constant current, charging characteristics as shown in FIG. 2 are obtained.

In other words, as the storage battery is charged by the charging device, the battery voltage increases and the battery recovers, and as charging progresses, the electrolyte in the battery is stirred, and the temperature of the electrolyte increases. Battery voltage is decreasing.

On the other hand, the time when the battery voltage is at its maximum is the time when charging is completed.

Then, before the charging completion time 0 in Fig. 2, the battery K ΔV /Δt of the unit time of the sample time is positive 9.
After time to, the voltage difference ΔV/Δt becomes negative, and the value of the voltage difference is smaller closer to time to.

Therefore, a device shown in FIG. 3 has conventionally been used as a charging completion detection device for detecting the negative value of the voltage difference.

In this Figure 3, (1) is a rectifier for charging, (2)
is a load storage battery connected to the rectifier (1), (3) is a charging completion detection device that receives the terminal voltage of the storage battery (2) as input,
(4) # (5) and (6) are the three resistances of the detection device (3) connected in series to both terminals of the storage battery (2), and the resistance (5) is the resistance (4) and ( 6) Select a smaller value and divide the terminal voltage Vo of the storage battery (2),
The i pressure vl is detected across the resistor (5).

(7) is a first operational amplifier in which the connection point of resistors (5) and (6) is connected to the non-inverting input terminal via a diode (8), and (9) is connected between the non-inverting input terminal and ground. and the first operational amplifier (7) e'
A peak value hold circuit is constituted by the /I, 1-dead (8) and the capacitor (9), and holds the peak value of the detected voltage at the connection point of the resistors (5) and (6).

The non-inverting input terminal of 00 is connected to the output terminal and the inverting input terminal of the first operational amplifier (7), and the inverting input terminal of 2 is connected to the resistor (4).
), is the second operational amplifier connected to the connection point of (5), and outputs a charging completion detection signal from the output terminal, stops the output of the rectifier (1), turns on the indicator light or light emitting diode, Notifies charging completion.

Next, the operation of the detection device will be explained.

Before charging is completed, the battery voltage difference ΔV/Δt for the unit time is positive, and the inverting input of the second operational amplifier α1 is larger than the non-inverting input, so the output of the second operational amplifier 00 is at a low level. .

Next, after charging is completed, the voltage difference ΔV/Δt becomes negative, so the inverting input of the second operational amplifier QQ becomes smaller than the non-inverting input, so the output of the second operational amplifier α0 becomes high level. , outputs a charging completion detection signal.

[Problem that the invention seeks to solve]

By the way, in order to hold the peak value in the hold circuit of the conventional detection device, a capacitor (9) of about 0.1 μF is usually used due to stability characteristics, and the capacitor (9) itself has a leakage current, and Since the capacitor (9) is usually mounted on a printed circuit board, charge may leak through the board.

Therefore, the hold circuit cannot hold a complete peak value.

Therefore, it is desirable to select a small value for the voltage across the resistor (5), but it is not possible to select a small value.
Charging completion cannot be accurately detected.

Note that the voltage across the resistor (5) can be detected as t o QmV if there is no leakage, but due to the leakage it can be detected as 50
If the voltage is not 0 mV, charging completion cannot be detected and accurate detection cannot be performed.

[Means for solving problems]

This invention was made with the above points in mind,
a resistor for detecting the battery voltage of the 'N battery to be charged; a circuit, a counter that counts and holds output pulses of the AND circuit, a digital/analog converter that converts the output of the counter into analog and inputs it as a reference signal to the first ratio diaphragm, and the reference signal and the resistor. A second detection voltage is input to the second detection voltage and outputs a charging completion notification signal.
This is a charging completion detection device characterized by comprising a ratio V.

[Effect]

Therefore, according to the present invention, the output of the first comparator and the clock pulse are input to the AND circuit, the output pulses of the AND circuit are counted by the counter, the count value is D/A converted, and the analog quantity is converted to the first comparator. Since it is used as the reference signal of the comparator and also as the non-inverting input of the second comparator, the resolution level can be increased and the completion of charging can be accurately detected.

〔Example〕

Next, this invention will be explained in detail with reference to FIG. 1 showing an embodiment thereof.

In the same figure, αη is a charging completion detection device that inputs the terminal voltage of the storage battery (2) in FIG. 3, and as in FIG. 8,
Eight series resistors (4) on both terminals of the storage battery (2).

(5) # (6) is connected.

Q2 is a first comparator consisting of an operational amplifier whose non-inverting input terminal is connected to the connection point of resistors (5) and (6), α [with] is a clock pulse generator that generates clock pulses,
(14) is an AND circuit into which the output signal of the first comparator a4 and the clock pulse from the clock pulse generator α field are input, and αQ is a counter that counts and holds the output pulses of the AND circuit.

α0 is a digital/analog converter (hereinafter referred to as a D/A converter) that converts the outputs of the counters α into analog signals and outputs a reference signal to the inverting input terminal of the first comparator α; This is a second comparator consisting of an operational amplifier to which a reference signal is input and whose inverting input terminal is connected to the connection point of resistors (4) and (5), and outputs a charging completion detection signal from its output terminal, as shown in Fig. 3. The output of the rectifier (1) is stopped, the indicator light 9 light-emitting diode, etc. is turned on, and charging completion is notified.

Next, the operation of the above embodiment will be explained.

When the detection device 0υ is activated, the value of the counter 00 is 0, and the output of the D/A converter Q6 is 0. The non-inverting input of the second comparator α is O, and the output of the second comparator αη is at a low level.

Next, as charging progresses, resistance (5) e (6
) is detected by the first comparator (
In order to input to the non-inverting input terminal of the first comparator (7)
) becomes high level, and the AND circuit α→ to which the output signal of the first comparator (7) and the clock pulse from the clock pulse generator (13) are input, outputs only when the clock pulse is input. The number of pulses within the sample time is counted by a counter αQ.

This counted digital value is sent to the D/A converter (11
3, it is converted into an analog quantity and inputted to the inverting input terminal of the first comparator 02 and the non-inverting input terminal of the second comparator α.

On the other hand, the divided voltage detected at the connection point between the resistors (4) and (5) is input to the inverting input terminal of the second comparator α.

Therefore, the output signal of the second comparator αη is at a low level since the inverting input is higher than the non-inverting input.

This state continues until time "to" in FIG. 2 is reached, the storage battery (2) is charged, and the battery voltage increases.

Now, if the count value of the counter (JQ) at time to is No, and the output of the D/A converter 00 of No is Va,
Since the battery voltage (at time to + Δt) is lower than that at time to, the inverting input Va of the first comparator α at time to + Δt becomes higher than the non-inverting input from the connection point of resistors (5) and (6). 1 The output of comparator α goes to low level.

Therefore, the output of the AND circuit α→ becomes 0, and the counter 0G holds the count value No at time to.

On the other hand, the second comparator 07) that compares the output Va of the D/A converter 01 with count value No. and the voltage at the connection point of the resistors (4) #(5) has a non-inverting input higher than an inverting input. , the output of the second comparator αη becomes high level, and a charging completion detection signal is output from the output terminal.

Furthermore, if the decomposition level of the counter 0Q is made finer, it is possible to more accurately detect the completion of the altitude. Specifically, it can be increased to 10 mV to 20 mV.

〔Effect of the invention〕

As described above, according to the present invention, r
Since OJ and rlJ pulses are counted, unlike conventional devices, there is no leakage due to capacitors, the level of decomposition can be increased, and the completion of charging can be accurately detected.

[Brief explanation of the drawing]

FIG. 1 is a wiring diagram of one embodiment of the charging JE completion detection device of the present invention, FIG. 2 is a charging characteristic diagram of a storage battery, and FIG. 3 is a wiring diagram of a conventional detection device. (4), (5)? (6)...resistance, o gong...
・First comparator, α snore...Clock pulse generator, α4)
...AND circuit, o average...counter, 00...D
/A converter, 0η...second comparator.

Claims (1)

[Claims] (1) A resistor that detects the battery voltage of the storage battery being charged;
a first comparator to which the first detection voltage of the resistor is input;
an AND circuit to which the output signal and clock pulses of the first comparator are input; a counter that counts and holds the output pulses of the AND circuit; A charging completion detection device comprising: a digital/analog converter for input; and a second comparator for receiving the reference signal and the second detection voltage of the resistor and outputting a charging completion notification signal.