JP3606088B2 - Initialization control circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an initialization control circuit for generating a reset signal when a rechargeable battery is discharged in a motor control circuit having a rechargeable battery and a charging circuit. More specifically, the present invention relates to a temporary battery voltage during motor control. The present invention relates to a technique for preventing an illegal reset signal from being generated due to a general degradation.
[0002]
[Prior art]
FIG. 9 is a circuit diagram of a conventional initialization control circuit. In the figure, 9 is a filter, 2 is a reset control IC, and 3 is a system unit. The filter 9 and the reset control IC 2 are added as external parts of the system unit 3 as a main body. When the power is turned on, the system is controlled by the reset control IC 2 that monitors the power supply voltage through the filter 9. Part initialization signal (reset signal) is generated, and the system part 3 is reset-controlled.
[0003]
[Problems to be solved by the invention]
In the conventional technique, since the reset control IC 2 and the filter 9 are required in addition to the system unit 3, the cost of the product is increased due to an increase in the board area and the number of parts. Therefore, it is conceivable to incorporate the reset control IC 2 and the filter 9 in the system unit 3. However, since the noise removal capability of the filter 9 is determined by the time constant CR, a large resistance and capacitance are required to remove large noise. Become. When the functions are integrated into one chip, the area occupied by the resistor and the capacitor is very large. Therefore, in order to reduce the price, it is desired to reduce the filter resistor and the capacitor. However, some systems with a built-in rechargeable battery and charging circuit and a control circuit that turns on and off the motor have a configuration in which the system unit is reset by monitoring the power supply voltage level of the rechargeable battery. The reset control unit may output an abnormal reset signal to the system due to power supply noise generated at ON / OFF. In such a case, a large filter is required to remove noise from the power supply signal, resulting in an increase in cost.
[0004]
The present invention solves the above-described problems, and an object of the present invention is to provide a low-cost initialization control circuit that does not increase the board area and the number of parts.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a motor control circuit having a rechargeable battery and a charging circuit, as shown in FIG. 1, at a timing at which noise caused by motor control is mixed in the power supply voltage of the rechargeable battery. Circuit for generating a window signal at the time of start-up or ON / OFF switching for motor rotation control , the window signal as a first input, the rechargeable battery power supply voltage as a second input, and a reset signal as outputs the power supply signal being monitored to produce Ru der which is characterized in that it comprises a logic circuit 1. As a result, even when noise is input from the power supply signal connected to the reset control unit 2 built in the IC at the time of starting the motor or switching ON / OFF for controlling the rotation of the motor , Since no regular reset signal is output to the system, malfunction of the system can be prevented.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Example 1
Examples of the present invention will be described below. FIG. 1 shows an initialization control circuit according to the first embodiment. In the figure, 1 is a logic gate, 2 is a reset control unit built in the IC, and 3 is a main body of the system unit. The window signal output from the system unit 3 is generated at the time of motor start-up or ON / OFF switching for motor rotation control, which is the timing at which noise due to motor control is mixed into the power supply voltage of the rechargeable battery, Is input to the logic gate 1 together with the power supply signal input from, and the operation of removing noise mixed in the power supply is performed. As described above, even when noise is generated in the power supply by the window signal output from the system unit 3, it is removed and the reset control unit 2 does not output an irregular system reset signal to the system unit 3. It has become. Therefore, noise can be removed without providing a large filter, and a low-cost initialization control circuit that does not increase the board area and the number of components can be realized.
[0007]
(Example 2)
FIG. 2 shows an initialization control circuit according to the second embodiment. The system unit 3 has a signal from the motor start switch, a system clock (CLK) and a power supply as inputs, a counter 4 that operates in response to the signal from the motor start switch, and a decoder A that decodes the count value of the counter 4. B, toggle type flip-flops 5 and 6 for generating a motor rotation control signal and a window signal.
[0008]
FIG. 3 is a timing chart showing the operation of the second embodiment. For the motor start, the output of the decoder B becomes HIGH for one clock at the time t1 after the falling signal is input from the motor start switch, and the window at the time t2. The signal becomes HIGH. At t3, the output of the decoder A becomes HIGH for one clock, and at t4, the motor rotation control signal becomes LOW, and the motor starts to rotate. Accordingly, noise is generated in the power supply. At t5, the output of the decoder B again outputs HIGH for one clock, and at t6, the window signal becomes LOW. By generating a window signal at time t2 to t6 during motor operation and preventing power supply noise from being input to the reset control unit 2, malfunction of the system unit 3 can be prevented.
[0009]
Example 3
FIG. 4 shows an initialization control circuit according to the third embodiment. In this embodiment, a toggle flip-flop 7 is added to the second embodiment, and the output is inverted upon receiving the falling input of the motor start switch. In the counter 4, the output of the toggle flip-flop 7 becomes LOW. Start counting. In addition, the logic of the decoders a and b is changed so that the window signal can be generated not only when the motor is started but also when the motor is turned on / off for motor rotation control (PWM control).
[0010]
FIG. 5 is a timing chart showing the operation of the third embodiment. The motor rotation control signal for switching the motor ON / OFF at the timing when the output of the decoder a falls is inverted. When this motor rotation control signal is LOW level, the motor is ON, and when it is HIGH level, the motor is OFF. A window signal is output from the toggle flip-flop 6 by a pulse output from the decoder b at the start of a motor operation in which noise is likely to be mixed into the power supply, that is, before and after the timing when the motor rotation control signal falls, to the OR gate 1 Input with power signal. Thereby, noise included in the power supply signal input to the reset control unit 2 can be removed.
[0011]
FIG. 6 shows a defective operation mode in the third embodiment. In a system having a system clock (CLK) ON / OFF function for reducing current consumption, the clock is also stopped by ON / OFF of a motor start switch which is a condition signal for stopping the clock. When the motor is turned off when the window signal is HIGH, the system clock is also stopped accordingly, so that the output of the OR gate 1 holds HIGH. In this condition, the power signal is reduced, even when trying to run normal reset, for LOW to the reset control unit 2 for the output of OR gate 1 is HIGH is not input, the normal system The reset cannot be executed. An embodiment in which this point is improved will be described below.
[0012]
Example 4
FIG. 7 shows an initialization control circuit according to the fourth embodiment. A clock ON / OFF control signal can be generated based on a signal input from the motor start switch, and the clock ON / OFF control signal is used as a reset signal of the toggle flip-flop 6 that generates a window signal. ing.
[0013]
FIG. 8 is a timing chart showing the operation of the fourth embodiment. When a motor stop signal is input from the motor start switch, the output of the toggle flip-flop 8 becomes LOW, and accordingly, the HIGH window signal is also reset, and the window signal becomes LOW. As a result, even if the motor is turned off while the window signal is HIGH, the window signal remains LOW. If the power supply level subsequently decreases and a normal reset needs to be performed, the LOW level is detected. Can be supplied to the reset control unit 2.
[0014]
【The invention's effect】
According to the present invention, a motor having a configuration in which a rechargeable battery and a charging circuit are held and a system unit is reset by monitoring a power supply level is controlled by an externally input power signal and a power supply voltage of the rechargeable battery. By gate processing the window signal generated at the time of motor start-up or ON / OFF switching for motor rotation control, which is the timing at which the resulting noise is mixed, by the power supply noise generated at the time of motor operation ON / OFF Since the reset controller prevents the abnormal reset signal from being output to the system, the conventional reset control IC and the filter for removing noise from the power supply signal are unnecessary, and the circuit scale is reduced. The price can be reduced.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of Embodiment 1 of the present invention.
FIG. 2 is a circuit diagram of Embodiment 2 of the present invention.
FIG. 3 is a timing chart showing the operation of the second embodiment of the present invention.
FIG. 4 is a circuit diagram of Embodiment 3 of the present invention.
FIG. 5 is a timing chart showing the operation of the third embodiment of the present invention.
FIG. 6 is a timing chart showing a defective operation mode according to the third embodiment of the present invention.
FIG. 7 is a circuit diagram of Embodiment 4 of the present invention.
FIG. 8 is a timing chart showing the operation of Embodiment 4 of the present invention.
FIG. 9 is a block diagram of a conventional example.
[Explanation of symbols]
1 Logic Gate 2 Reset Control Unit 3 System Unit 4 Counter A Decoder B Decoder 5 Toggle Flip-Flop 6 Toggle Flip-Flop

Claims (3)

A motor control circuit having a rechargeable battery and a charging circuit includes a circuit that generates a window signal at the time of starting the motor, which is a timing at which noise caused by motor control is mixed with the power supply voltage of the rechargeable battery. An initialization control circuit comprising: a logic circuit that receives a power supply voltage of the rechargeable battery as a second input and outputs a power supply signal monitored to generate a reset signal. In a motor control circuit having a rechargeable battery and a charging circuit, a circuit for generating a window signal at the time of ON / OFF switching for motor rotation control, which is a timing at which noise caused by motor control is mixed in the power supply voltage of the rechargeable battery, is provided Initialization characterized by comprising a logic circuit that uses the window signal as a first input, the power supply voltage of the rechargeable battery as a second input, and outputs a monitored power signal to generate a reset signal Control circuit. 3. The initialization control circuit according to claim 1, further comprising a system clock ON / OFF function, wherein the window signal is reset when the system clock is OFF.

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