JPH0756610A - Mode switching circuit for controller - Google Patents

Abstract

PURPOSE:To reset a controller to a normal operation mode from a low power consumption mode when each operation switch is changed to an ON state from an OFF state. CONSTITUTION:When one of switches SW1-SW3 is changed to an ON state from an OFF state while these switches are kept in an OFF state, a detecting part 11 detects this change and transmits a detection signal to a reset signal generating part 12. The part 12 transmits the reset signal to a reset terminal CE of a microcomputer 3 serving as a controller. Thus the microcomputer 3 is reset to a normal operation mode from a low power consumption mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mode switching circuit of a control device for returning a control device such as a microcomputer having a low current consumption mode from a low current consumption mode to an operation mode.

[0002]

2. Description of the Related Art Conventionally, for example, an automobile is equipped with an electronic unit consisting of a microcomputer (hereinafter, referred to as a microcomputer) for controlling various loads, and this microcomputer operates in a normal operation mode for controlling the operation of each load. Under the condition that a current of about mA is consumed but it is not necessary to control each load, as described in JP-A-62-187905, the oscillation called sleep mode is stopped to reduce the current consumption. It is considered to shift to a low current consumption mode designed for reduction, and various microcomputers having such a low current consumption mode are provided.

When a microcomputer having such a low current consumption mode is used in the on-vehicle electronic unit described above, a reset terminal of the microcomputer is used to return the microcomputer from the low current consumption mode to the normal operation mode. It is necessary to give a return signal.

[0004]

However, in general, in the case of an on-vehicle electronic unit, there are many kinds of loads to be controlled,
In addition, a plurality of operation switches for turning these loads on and off are also provided. If the signals resulting from the inversion of these switches from on to on are used as the return signals, the types of the return signals are high level signals and low level signals. In addition, there are multiple rising, falling, etc., whereas the microcomputer normally has only one return terminal, so it is difficult to return to the operating mode of the microcomputer in response to all types of return signals. However, it is impossible to reduce the current consumption of the electronic unit to the maximum because measures such as intentionally avoiding the use of the low current consumption mode and limiting the usage conditions of the low current consumption mode to specific ones are taken. It was

Therefore, the present invention has been made in order to solve the above problems, and when the operation switches are turned from OFF to ON, the control device is returned from the low current consumption mode to the normal operation mode. The purpose is to be able to.

[0006]

A mode switching circuit of a control device according to the present invention outputs a drive control signal by turning on an input signal by operating an operation switch for various loads in an operation mode to output a drive control signal. A control device that performs control and shifts from the operation mode to the low current consumption mode when a condition that does not require output, such as turning off the input signal or changing the input signal, is satisfied.
When a condition that requires output, such as the turning on of the input signal or the occurrence of a change in the input signal, is satisfied, a return signal is output to the return terminal of the control device to bring the control device out of the low current consumption mode. In the mode switching circuit of the control device for returning to the operation mode, a detection unit which detects a reversal of each of the operation switches from off to on and outputs a detection signal, and the recovery signal by inputting the detection signal. And a return signal generator for outputting

[0007]

In the present invention, when one of the operation switches for each load is operated to turn it from off to on,
The inversion is detected by the detection unit, the detection signal is output to the return signal generation unit, the return signal is output from the return signal generation unit to the return terminal of the control device, and the control device switches from the low current consumption mode to the normal operation mode. Return.

[0008]

1 is a connection diagram of an embodiment of the present invention, and FIG. 2 is a timing chart for explaining the operation.

In FIG. 1, 1 is a battery, SW1 is an ignition switch, SW2 is a door switch which is turned on and off according to opening and closing of a door, SW3 is a small lamp switch, and these switches SW1 to SW3 are various loads. Corresponding to the operation switch for
When the SW3 is turned on, the input circuits 2a, 2b, 2
c operates to supply a switch input signal to the input terminal of the microcomputer 3 as a control device, whereby the microcomputer 3 enters a normal operation mode and the output terminals of the microcomputer 3 control the drive circuits 4a, 4b, 4c. A signal is output and each drive circuit 4a, 4b, 4c is appropriately controlled to drive various lamps 5a, 5b, 5c as loads and other loads not shown.

The power supply terminal of the microcomputer 3 is supplied with power via a power supply circuit 6 connected to the battery 1.

Then, the microcomputer 3, each input circuit 2a-2
c, the drive circuits 4a to 4c and the power supply circuit 6 are unitized to form an electronic unit 7. The electronic unit 7 controls the seat belt warning when the switch SW1 is turned on, and the room lamp is turned on when the switch SW2 is turned on. The headlights are controlled when the lighting control is performed and the switch SW3 is turned from ON to OFF and vice versa.

By the way, the microcomputer 3 has a low current consumption mode function called a sleep mode, and the input circuits 2a to 2 by turning off all the switches SW1 to SW3.
When a condition that does not require the output of the microcomputer 3 is satisfied, such as turning off the input signal from c or changing the input signal, the operation mode shifts to the low current consumption mode, while the high level to the recovery terminal CE is set. By inputting a return signal (hereinafter referred to as H), the low current consumption mode is returned to the normal operation mode.

Thus, in order to return the microcomputer 3 from the low current consumption mode to the normal operation mode, the electronic unit 7 is provided with the following mode switching circuit 10.

As shown in FIG. 1, the mode switching circuit 10 includes a detection section 11 including resistors R1 to R5, capacitors C1 to C3, diodes D1 and D2 and transistors Q1 and Q2, resistors R6 to R9 and a transistor Q3. And a return signal generating section 12 including.

Then, from the state in which each of the switches SW1 to SW3 is off, as shown in FIG.
When only W1 is turned on, diode D1 and resistor R
A base current is supplied to the NPN transistor Q2 via 4 and the base voltage rises from the GND level to the + B level to turn on the transistor Q2.
Is turned on, the PNP transistor Q3 is turned on and the collector voltage of the transistor Q3 rises to the _VDD level.
As shown in (d), the return signal of H is supplied to the return terminal CE of the microcomputer 3, the microcomputer 3 returns from the low current consumption mode to the normal operation mode, and the signal is input from the input circuit 2a to the microcomputer 3. The seatbelt warning control is performed by the microcomputer 3.

On the other hand, as shown in FIG. 2A, the switch S
When only the switch W1 is turned on, it is turned off, and when all the switches SW1 to SW3 are turned off, the base voltage of the transistor Q2 drops from the + B level to the GND level, the transistor Q2 turns off, and the transistor Q2 turns off.
The base voltage of 3 rises to V _DD level, and the transistor Q
3 is turned off, the collector voltage drops to the GND level, the reset terminal CE of the microcomputer 3 becomes low level (hereinafter referred to as L), and the microcomputer 3 shifts to the low current consumption mode, as shown in FIG. 2 (d). , The current consumption of the electronic unit 7 is reduced.

Next, from the state in which each of the switches SW1 to SW3 is off, as shown in FIG.
When only W2 is turned on, diode D2 and resistor R
Since the base of the transistor Q3 is grounded via the transistor 8, the base voltage of the transistor Q3 changes from V _DD level to G
2D, the transistor Q3 is turned on, the collector voltage of the transistor Q3 rises to V _DD level, and a reset signal of H is supplied to the reset terminal CE of the microcomputer 3 as shown in FIG. 3 returns from the low current consumption mode to the normal operation mode, a signal is input from the input circuit 2b to the microcomputer 3, and the microcomputer 3 controls the room lamp.

Further, as shown in FIG. 2B, when only the switch SW2 is turned on and then all switches SW1 to SW3 are turned off, the base voltage of the transistor Q3 becomes GND level. Rises to V _DD level, the transistor Q3 is turned off, the collector voltage of the transistor Q3 drops to GND level, and FIG.
As shown in (d), the reset terminal CE of the microcomputer 3 becomes L, the microcomputer 3 shifts to the low current consumption mode, and the current consumption of the electronic unit 7 is reduced.

Further, from the state where each of the switches SW1 to SW3 is off, as shown in FIG.
When only W3 is turned on, PNP is connected via resistor R1.
Since the base of the transistor Q1 is grounded, the transistor Q
1 is turned on and the collector voltage of the transistor Q1 is GND
The level rises from the level to + B level, and the differentiation circuit composed of the capacitor C2 and the resistance R4 works to make the resistance R
The charge of the capacitor C2 is discharged via 4
The base of the transistor Q2 becomes H for a fixed time t determined by the discharge time constant, and the transistor Q2 is turned on. While the transistor Q2 is turned on, the transistor Q3 is also turned on and its collector voltage is held at the _VDD level. Therefore, as shown in FIG. 2D, the reset terminal CE of the microcomputer 3 becomes H for t time after the switch SW3 is turned on, the microcomputer 3 returns from the low current consumption mode to the normal operation mode, and the input circuit 2c A signal is input to the microcomputer 3 from the microcomputer 3 and the headlight is controlled by the microcomputer 3.

By the way, after a lapse of time t from when the switch SW3 is turned on, the transistor Q2 is turned off and the transistor Q3 is turned off. As shown in FIG.
The reset terminal CE of the switch SW becomes L, and the switch SW3 becomes
Even if the computer is left on for a long time, the microcomputer 3
Shifts to the low current consumption mode, and the current consumption of the electronic unit 7 is reduced.

On the other hand, as shown in FIG. 2 (c), when only the switch SW3 is turned on and the state is turned off and all the switches SW1 to SW3 are turned off, the base voltage of the transistor Q1 is at the GND level. To + B level, the transistor Q1 is turned off, the collector voltage of the transistor Q1 decreases from + B level to GND level, and the constant of the discharge time constant is determined by the function of the differentiation circuit composed of the capacitor C3 and the resistor R8. Only for the time t ′, the base of the transistor Q3 becomes L, the transistor Q3 is turned on, the collector voltage of the transistor Q3 is held at the _VDD level, and as shown in FIG. 2D, the switch SW3 is turned off t Until the time elapses, the reset terminal CE of the microcomputer 3 becomes H, and the microcomputer 3 goes into the normal operation mode. It is lifting becomes possible to cancel such an automatic off control of headlights.

Further, after a lapse of time t'after the switch SW3 is turned off, the transistor Q3 is turned off and the collector voltage of the transistor Q3 is lowered to the GND level, and the microcomputer 3 is restored as shown in FIG. 2 (d). The terminal CE becomes L, the microcomputer 3 shifts to the low current consumption mode, and the current consumption of the electronic unit 7 is reduced.

Therefore, even if there are a plurality of operation switches,
The mode switching circuit 10 can apply one kind of return signal to the return terminal CE of the microcomputer 3 to return from the low current consumption mode to the normal operation mode.

When all the switches SW1 to SW3 are off, the microcomputer 3 can be shifted to the low current consumption mode to reduce the current consumption.

Needless to say, the mode switching circuit is not limited to the configuration shown in FIG.

[0026]

As described above, according to the present invention, the control device is returned from the low current consumption mode to the normal operation mode even if there are a plurality of operation switches and only one return terminal of the control device. Therefore, it is not necessary to avoid the use of the low current consumption mode or limit the use condition as in the conventional case, and it is suitable for an electronic control device for an automobile.

[Brief description of drawings]

FIG. 1 is a connection diagram of an embodiment of a mode switching circuit of a control device of the present invention.

FIG. 2 is a timing chart for explaining the operation of FIG.

[Explanation of symbols]

 3 Microcomputer SW1 to SW3 Switch 11 Detector 12 Return signal generator

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G06F 1/32

Claims (1)

[Claims] 1. In an operation mode, when an input signal is turned on by operating an operation switch for various loads, a drive control signal is output to control each load, and the input signal is turned off or the input signal changes. A control device that shifts from the operation mode to a low current consumption mode when a condition that there is no need for output is satisfied, such as when the input signal is turned on or a change occurs in the input signal. When a certain condition is satisfied, a return signal is output to a return terminal of the control device to return the control device from the low current consumption mode to the operation mode. A detection unit that outputs a detection signal by detecting the inversion of any of the above from OFF to ON, and a return signal that outputs the return signal when the detection signal is input. Mode switching circuit of the control apparatus characterized by comprising a generating unit.