JP2503336B2 - Overcharge prevention method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overcharge prevention system for preventing overcharge of a battery.

[0002]

2. Description of the Related Art In a microcomputer (hereinafter, referred to as a microcomputer) that controls charging of a battery, if the microcomputer runs out of control for some reason and the charging is not completed within a predetermined time, the performance may be deteriorated due to overcharging of the battery. In the worst case, a situation of burning out occurs. As a countermeasure against this, conventionally, there has been a method of detecting a runaway with a watched timer for a microcomputer and starting a charging operation only when the microcomputer is reset and a normal operation is started.

[0003]

The method of resetting the microcomputer and starting the operation by the above-described conventional watched timer has the following problems.

(1) If a runaway is detected and the charging operation is stopped by resetting the microcomputer, it is possible to prevent the battery from burning, but even if the cause of the runaway is temporary, the charging operation is restored. There is a problem that it cannot be started again.

(2) When the microcomputer is reset and started from the initial charging state, there is a problem that overcharging occurs even though the battery can be prevented from burning. (3) If the device that detects runaway of the microcomputer consumes a large amount of power, there is a problem that it cannot be used in a system that requires power saving.

In order to solve these problems, the present invention detects a runaway in an external circuit of the microcomputer, holds and resets the result, starts the microcomputer, and restarts charging based on the held result. The purpose is to prevent overcharging of the battery due to runaway and restart charging.

[0007]

FIG. 1 is a block diagram showing the principle of the present invention. In FIG. 1, the microcomputer 1 includes a battery 8
The charging control is performed by setting / referring to the charging table 11 which integrates the charging time.

The runaway detecting section 2 detects a runaway of the microcomputer 1. The result holding unit 5 holds the runaway result detected by the runaway detection unit 2. The charging control unit 7
The charging of the battery 8 is controlled in response to a charging instruction from the microcomputer 1.

[0009]

According to the present invention, as shown in FIG. 1, the microcomputer 1 instructs the charging control unit 7 to start charging the battery 8 and sets the charging time in the charging table 11 to detect runaway during charging control. In response to the detection of the runaway of the microcomputer 1 by the unit 2, the result holding unit 5 holds the runaway result and the microcomputer 1 is reset, and the reset result of the microcomputer 1 held by the result holding unit 3 is runaway. When it is determined that the charging table 11 is left as it is, the other tables are initialized and the charging is continued based on the charging table 11.

Therefore, the external circuit independent of the microcomputer 1 detects the runaway, holds and resets the result, starts the microcomputer 1 and restarts the charging, whereby the microcomputer 1
It is possible to prevent the battery 8 from being overcharged due to the runaway and restart the charging.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the construction and operation of an embodiment of the present invention will be described in detail with reference to FIGS.

FIG. 1 is a block diagram showing the principle of the present invention. FIG.
3, the microcomputer 1 sets / refers to the charging table 11 that accumulates the charging time of the battery 8 and notifies the charging control signal of the charging instruction signal to charge the battery 8 (see the microcomputer 1 of FIG. 3). See flow chart). Here, the microcomputer 1 sends a pulse signal of a predetermined width to the runaway detection unit 2 at a predetermined time interval to detect the runaway of the microcomputer 1 (see FIG. 4), or the runaway detection unit 2 detects the runaway of the microcomputer 1. In response to this, the reset generator 3 inputs the reset signal RST to reset and restart the microcomputer 1 (see S2 in FIG. 3) or reset the result holder 5 to release the charge stop signal. Or reset generator 3
When the reset signal RST is input from the device and the device is reset and restarted, the notification of the reset factor is read from the result holding unit 5 (see S6 in FIG. 3), and the charge instruction signal is AND
It is input to the circuit 6 to supply a charge permission signal to the charge control unit 7 to charge the battery 8, or when the battery is reset and restarted, the charge control unit 7 is instructed to rapidly charge the battery 8 and At this time, −ΔV is detected to obtain the charging ratio of the already charged battery, and the remaining charge amount is calculated.

The charging table 11 is used to set a charging time for charging the battery 8 (charging time integration time), a remaining amount value of the battery 8 and the like. The runaway detection unit 2 detects that the microcomputer 1 has runaway when a pulse signal of a predetermined width is interrupted from the microcomputer 1 at a predetermined time interval (see FIGS. 2 and 4). When a runaway of the microcomputer 1 is detected, the runaway generation signal is notified to the reset generation unit 3 to generate a reset signal, the microcomputer 1 is reset and restarted, and the runaway generation signal (runaway signal) is held as a result. The unit 5 is notified and the fact (result) of the runaway during charging is held.

The reset generation section 3 generates a reset signal RST and inputs it to the microcomputer 1 in response to the notification of the runaway signal of the runaway of the microcomputer 1 from the runaway detection section 2 and inputs it to the microcomputer 1. Is to reset and restart.

The AND circuit 4 generates a result (runaway signal) of the runaway occurrence signal detected by the runaway detecting unit 2 and the reset signal from the reset generating unit 3.

The result holding unit 5 receives an AND from the runaway detection unit 2.
When the notification of the runaway signal is received through the circuit 4, this fact (runaway) is held (see FIG. 2). AN
The D circuit 6 receives the charge stop signal * CHG from the result holding unit 5.
When DS is inactive and the charging instruction signal from the microcomputer 1 is active, the charging permission signal is notified to the charging control unit 7 and the battery 8 is charged. Active charge stop signal * CHGDS from result holder 5
Is input to the AND circuit 6, the charging of the battery 8 is stopped.

The charge control section 7 supplies a predetermined current to the battery 8 to charge it in response to the charge permission signal from the AND circuit 6. FIG. 2 is a configuration diagram of an embodiment of the present invention, which is a specific circuit example of FIG.

In FIG. 2, the microcomputer 1 has a ROM 12
MPU (microprocessor) 11 that performs various processes in accordance with the programs therein, R that writes various programs in advance
It comprises an OM 12, a RAM 14 for storing data and intermediate results, and providing a charging table 11. In the charging table 11, the accumulated charging time of the battery 8 and the remaining amount of the battery 8 are set.

The runaway detecting section 2 receives a pulse signal PULSLE of a predetermined width from the microcomputer 1 at a predetermined time interval, and R
When the pulse signal PULSE is not input for a predetermined time determined by the time constant of 1 × C1, the microcomputer 1 detects that it has runaway and sends a runaway generation signal via IC1 or IC4, or R2 × C2 When a pulse signal PULSE having a pulse width longer than a predetermined time determined by the time constant is input, it is detected that the microcomputer 1 has runaway and IC3, IC4
A runaway generation signal is sent via the (see FIG. 4 in detail).

The reset generating section 3 generates a reset signal having a predetermined width determined by the time constant of R3 × C3 in response to the runaway generating signal from the runaway detecting section 2. The AND circuit 4 performs an AND operation on the runaway generation signal from the runaway detection unit 2 and the reset signal from the reset generation unit 3, and outputs the runaway signal to the result holding unit when both signals are input. 5 is input to the reset terminal.

The result holding unit 5 presets the FF in response to the system reset signal from the microcomputer 1 and sends an inactive charge stop signal * CHGDS to charge the battery 8, while the AND circuit 4 The FF is reset in response to the runaway signal from and the active charge stop signal * CHGDS is sent to stop the charging of the battery 8.

The AND circuit 6 performs an AND operation of the charge stop signal * CHGDS from the result holding section 5 and the charge instruction signal from the microcomputer 1 to obtain the inactive charge stop signal * CHGDS and the active charge instruction signal. At times, a charge permission signal is generated and supplied to the charge control unit 7 to charge the battery 8.

The charging control unit 7 supplies a predetermined current to the battery 8 to charge it in response to the charging permission signal, or rapidly charges the battery 8 to detect -ΔV at that time and notifies the microcomputer 1 to notify the battery. The remaining charge amount of 8 is calculated.

The battery 8 is a battery to be charged. Next, the operation of the configuration of FIGS. 1 and 2 will be described in detail according to the order shown in the flowchart of FIG.

In FIG. 3, S1 detects runaway. This is because the runaway detection unit 2 uses the pulse signal P from the microcomputer 1.
It is detected that ULSE is no longer input at a predetermined time interval, or that the pulse width of the pulse signal PULSE from the microcomputer 1 has become equal to or longer than a predetermined time, and the microcomputer 1 recognizes that it has runaway.

S2 issues a reset. This is S1
In response to the detection of the runaway in (1), the reset generator 3 generates a reset signal RST having a predetermined width, which is input to the reset terminal of the microcomputer 1 and restarted.

S3 holds the result. This is because in response to the runaway detection in S1 and the generation of the reset signal RST in S2, the fact that the result holding unit 5 has runaway is stored, that is, the FF is reset and stored, and the active charge stop signal * CHGDS is stored. Is output and an inactive charge permission signal is input to the charge control unit 7 via the AND circuit 6 to stop charging the battery 8.

S4 corresponds to the reset issuance of S2,
The microcomputer 1 starts the reset process. The microcomputer 1 initializes S5.

In step S6, the reset factor is confirmed. For this, the microcomputer 1 determines whether or not it is the inactive charge stop signal * CHGDS held by the FF of the result holding unit 5, and confirms whether the reset is caused by a runaway during charging.

In step S7, it is determined whether a runaway occurs during charging. Y
In the case of ES, the charging table 11 is left as it is without being cleared in S8, other tables are cleared in S9, and S10 is set.
Control (charging control) is restarted, that is, the system reset signal is notified to the result holding unit 5 to reset the FF, the inactive charging stop signal * CHGDS is sent, and the charging time integrated amount of the charging table 11 is referred to. Then, a charge instruction signal is output for the remaining time, and the charge control unit 7 is instructed to charge the battery 8. On the other hand, if NO in S7, it is not reset due to runaway during charging, so S1
All tables (including the charging table 11) are cleared at 1 and the corresponding control is restarted.

As described above, the microcomputer 1 sends the pulse signal PULSE having a predetermined pulse width at a predetermined time interval so that the runaway detecting section 2 of the hardware does not input the pulse signal PULSE at a predetermined time interval, or the pulse signal PULSE exceeds a predetermined width. When the pulse width is reached, it is determined that the microcomputer 1 has gone out of control, a reset signal is generated, the microcomputer 1 is reset and restarted, and the reset factor is stored as a runaway during charging and restarted. When the microcomputer 1 fetches the information about the runaway during charging, the charging table 11 is left as it is and the other tables are cleared, and the remaining charging is restarted based on the accumulated charging time of the charging table 11. As a result, it is possible to prevent the battery 8 from being overcharged due to the runaway of the microcomputer 1, and to reset and refer to the charging table 11 to continue the remaining charging. At this time, in order to confirm the remaining charge amount, the battery 8 is rapidly charged and −ΔV at that time is calculated to obtain the battery 8
It is also possible to measure and confirm the remaining amount of the battery, and perform appropriate charging with higher protection.

FIG. 4 shows an illustration of runaway detection according to the present invention.
This explains the runaway detection when the runaway detection unit 2 of FIG. 2 runs out of control based on the predetermined time interval and pulse width of the pulse signal PULSE input from the microcomputer 1.

FIG. 4A shows the waveform when the pulse output (pulse signal PULSE in FIG. 2) is normal. here,
The pulse interval is within 500 ms and the pulse width is 2
The case where it is 00 μs or more and 30 ms or less is regarded as normal.

FIG. 4B shows a waveform when the pulse output (pulse signal PULSE in FIG. 2) is abnormal. Abnormality is when the pulse time interval is 500 ms or more or there is no pulse,
Alternatively, the pulse width is 30 ms or more.

FIG. 4C shows a case where a runaway due to the interval of the pulse signal PULSE output from the microcomputer 1 is detected. (Ha 1) of FIG. 4 shows a normal time. In this normal state, the input voltage (voltage of pulse signal PULSE signal)
Is the resistance R1, the capacitor C1, and the runaway detector 2 of FIG.
When input to the circuit composed of the diode D1 and the gate IC1, the capacitor C1 is rapidly charged through the diode D1 in the positive pulse portion, and when the positive pulse disappears, R1 × C1 is set, for example, 200 K ohm × 3. It gradually discharges with a time constant of 3 μF = 660 ms. For example, the next pulse signal PUL is delivered within 660 ms.
If SE is repeatedly input, the capacitor C1 is rapidly charged again by the diode D1, so that the gate IC1 having hysteresis does not invert, the output remains at L level, and no runaway is detected.

FIG. 4 (H2) shows a runaway. During this runaway, input voltage (voltage of pulse signal PULSE)
Is the resistance R1, the capacitor C1, and the runaway detector 2 of FIG.
When input to the circuit composed of the diode D1 and the gate IC1, the capacitor C1 is rapidly charged through the diode D1 in the positive pulse portion, and when the positive pulse disappears, R1 × C1 is set, for example, 200 K ohm × 3. Although it is gradually discharged with a time constant of 3 μF = 660 ms, since the next pulse signal PULSE is not input, for example, the gate IC1 having hysteresis is inverted at a position where a time constant of 660 ms has elapsed, the output becomes H level, and runaway occurs. To detect. The detected runaway signal is the gate IC
4 (OR circuit) as a runaway generation signal.

FIG. 4D shows a case where a runaway due to the pulse width of the pulse signal PULSE output from the microcomputer 1 is detected. (Knee 1) in FIG. 4 indicates a normal time. During this normal time, input voltage (voltage of pulse signal PULSE)
2 is input to the circuit composed of the resistor R2, the capacitor C2, and the gate IC3, the signal inverted by the gate IC2 of the runaway detection unit 2 in FIG.
As an example, 200K ohm × 0.1 μF = 20 ms
Since the charging and discharging are repeated gradually with the time constant of, the gate IC4 having hysteresis does not invert and the output is L
It remains at the level and does not detect runaway.

FIG. 4 (knee 2) shows a runaway. During this runaway, a pulse signal obtained by inverting the input voltage (voltage of the pulse signal PULSE signal) is applied to the resistor R2 and the capacitor C.
When inputting to 2, the gate IC has hysteresis when the pulse width exceeds 20 ms and drops below a predetermined voltage.
3 is inverted, the output becomes H level, and runaway is detected. The detected runaway signal is sent as a runaway generation signal via the gate IC 4 (OR circuit).

The microcomputer 1 having the circuit configuration shown in FIG.
It is possible to detect the runaway of.

[0040]

As described above, according to the present invention,
Since an external circuit of the microcomputer 1 detects a runaway, holds and resets the result, starts the microcomputer 1 and restarts charging, the overcharge of the battery 8 due to the runaway of the microcomputer 1 is prevented. The charging can be resumed while the charging can be achieved. As a result, with a simple circuit configuration and with extremely low current consumption, resetting and recharging can be performed when the microcomputer is out of control, preventing performance deterioration due to overcharging of the battery, preventing the worst burning, and charging table 11. It is possible to appropriately charge the remaining charge by referring to the set accumulated charge amount.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of the present invention.

FIG. 2 is a configuration diagram of one embodiment of the present invention.

FIG. 3 is a flowchart for explaining the operation of the present invention.

FIG. 4 is a diagram illustrating runaway detection according to the present invention.

[Explanation of symbols]

 1: Microcomputer 11: Charging table 12: MPU 13: ROM 14: RAM 2: Runaway detection unit 3: Reset generation unit 4, 6: AND circuit 5: Result holding unit 7: Charge control unit 8: Battery

Claims (1)

(57) [Claims] 1. In an overcharge prevention system for preventing overcharge of a battery, setting / reference means for setting / referring to a charging table (11) for accumulating charging time of the battery, and full charge of the battery.
A microcomputer (1) having full-charge detecting means for detecting, and a runaway detecting section (2) for detecting runaway of the microcomputer (1).
And a result holding section (5) for holding the runaway result detected by the runaway detecting section (2), wherein the microcomputer (1) starts charging the battery and the setting / reference means sets the charging time to the charging. In response to the runaway detection unit (2) detecting the runaway of the microcomputer (1) during charging control set in the table (11), the runaway result is held in the result holding unit (5). Microcomputer (1)
When the reset microcomputer (1) finds that the runaway result is held in the result holding unit (5), the charging table (11) is left as it is and other tables are initialized to charge this charging. When charging is continued based on the table (11) and it is determined that the battery is fully charged, or
The full charge detecting means in the controller (1) is based on the voltage of the battery.
An overcharge prevention method, which is configured to stop charging when full charge is detected .