JP2610829B2 - Electronic clock - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a motor drive control system for an analog electronic timepiece.

[Summary of the Invention]

The present invention provides means for detecting a voltage value of a power supply voltage and initializing a driving pulse width in a motor driving method of an analog electronic timepiece using a pulse width adaptive control method.

[Conventional technology]

Conventionally, as shown in FIG. 2, the motor is normally driven by a normal drive pulse P ₁ having a relatively small pulse width. If the motor cannot be rotated by the normal drive pulse P ₁ , 31.25 msec from P ₁ later, normally outputs wider the correction driving pulse P ₂ having sufficiently pulse width than the drive pulse P _1, method for re-driving the motor are invented. FIG. 3 shows a block diagram of a conventional drive type quartz timepiece. An oscillation circuit 1 includes a crystal. A frequency dividing circuit 2 for dividing the output signal from the oscillation circuit 1, a waveform synthesizing circuit 3 receiving the output of the frequency dividing circuit 2 and sending necessary pulses to the driving circuit 5, the control circuit 4, and the rotation detecting circuit 7;
And a power source 9 for supplying energy to each circuit. FIG. 4 is a flowchart of a conventional driving method. Here, n is an integer having a value of 0 to 6. ΔP is set to 0.244 msec, P ₀ is set to 2.0 msec, and P ₂ is set to 7.8 msec. After starting in step 50, step 51
To initialize by inputting 0 to N ₁ n respectively. Step 51
Then, the calculation of P ₁ = P ₀ + △ P · n is performed.
Since it is 0, P ₁ = 2.0 msec. In step 53 outputs a normal driving pulse P _1. In step 54, it detects the rotation of the rotor at P _1. If the rotor is not rotating, step 55
In outputting a correction driving pulse P _2. Then, at step 56, one is added to the content of n, and the routine proceeds to step 57. If, when the rotor in the normal driving pulse P ₁ has been detected to have rotated, the process proceeds to step 57. In step 57, it is checked whether N has reached 320. If N is less than 320, 1 is added to the content of N, and the routine proceeds to step 52. If N = 320, enter 0 for N, subtract 1 from the contents of n,
Proceed to step 52. Thereafter, a similar loop is repeated. When this flowchart is executed, the pulse width of the normal drive pulse P ₁ is variable according to the output from the rotation detection circuit of the rotor, and P ₁ = 2.0 msec, 2.2 msec, 2.4 msec, 2.7 m
There are seven types: sec, 2.9 msec, 3.2 msec, and 3.7 msec.

This method is disclosed in, for example, JP-A-54-77163, and is already known. Here steps 51 and 5
2, 56, 57, 58 and 59 are performed by the control circuit 4. Steps 53 and 55 are outputs of the drive circuit 5, and step 54 is an output of the rotation detection circuit.

[Problems to be solved by the invention]

Since the conventional analog electronic timepiece as described above uses a silver battery as an energy source, it is not necessary to consider the fluctuation of the power supply voltage from the flatness of the voltage of the silver battery. Therefore, the variable range of the normal pulse width of the drive pulse P ₁ vary depending on the load, was good considering the battery voltage of about 1.57v as constant.

However, in analog electronic watches and the like that use a solar cell (solar cell) attached to the dial surface or the like as an energy supply, the energy of the solar cell is transferred to a large-capacity capacitor,
Motors and ICs are temporarily stored in a secondary power supply such as a secondary battery, and discharged from the secondary power supply when the solar cell is not exposed to light at night or the like. A large-capacity capacitor is frequently charged and discharged repeatedly, and its voltage is not determined. In such a timepiece in which the power supply voltage greatly changes, the driving condition of the motor changes depending on the power supply voltage. Therefore, if the conventional rotation detection principle is used as it is, the rotation detection of the motor is not normally performed. Occurs.

One example is shown in FIG. The horizontal axis represents the pulse width of P _1, the vertical axis Figure 5 shows the voltage induced in the coil of the step motor by damped oscillation of the rotor. The induced voltage is characterized in that it increases when the rotor of the step motor rotates, and decreases when it does not rotate. On the circuit, when the induced voltage is equal to or higher than Vth, it is determined that the motor is rotating, and when the induced voltage is equal to or lower than Vth, the motor is not rotating. However, rotation of the rotor in the induced voltage, non-rotation there is a limit to the range of normal pulse width of the drive pulse P ₁ which can be detected correctly, hereinafter it with P ₁ max. Normally, increasing the pulse width makes the motor easier to rotate, but the pulse width is P ₁
In the vicinity of max, the driving force of the rotor itself is weakened, and the damped vibration of the rotor is reduced. As a result, the induced voltage is lowered even though the rotor is rotating, and the rotor is not rotated, resulting in erroneous detection. There is a limit to the range of the pulse width of P ₁ pulses such as the rotation detection of the rotor is successful.

FIGS. 5A and 5B show the induced voltages when the voltage applied to the motor is changed, respectively, where a is when the power supply voltage is low and b is high. Also, the threshold voltage Vth,
And the pulse width range P _{1 in which} row rotation detection is normally performed
It shows from max to P ₁ min. When the power supply voltage is low, the reference voltage Vtha of the comparator for determining rotation / non-rotation becomes low because the power supply voltage is usually determined by resistance division. In addition, the minimum pulse width at which the rotor can rotate is around P ₁ mina, and around this vicinity, the induced voltage of the coil increases. Thereafter, the induced voltage is clamped to a certain voltage by the diode characteristics of the motor drive circuit, and the flat state continues. When the pulse width is further increased, P ₁ maxa in which the induced voltage decreases despite the rotation of the rotor appears for the reason described above. This P ₁ min a
Normal rotation can be detected in the pulse width range from to P ₁ maxa.

Next, when the state of the power supply voltage becomes high b, the driving condition of the rotor changes, so that the rotation of the rotor starts to be started with a shorter pulse width than when the power supply voltage is low, and P ₁ min b and P ₁ max b are equal to the P ₁ mi
The pulse width is shorter than na and P ₁ max a.

From these facts, in the conventional motor drive system, when the power supply voltage suddenly changes from the state a to the state b, an erroneous detection area in which the rotor is determined to be non-rotating even though the rotor is rotating is present. It will exist.

If there is an area where erroneous detection occurs, the normal drive pulse
Will be P ₁ and the correction driving pulse P ₂ is always output, power consumption had disadvantage increases.

[Means for solving the problem]

The present invention, in order to solve the above problems, detects a power supply voltage such as a capacitor, P ₁ the value of P ₁ max from P ₁ max a when the power supply voltage is changed suddenly high from low max b
And P ₁ min was started from P ₁ min b.

[Action]

When the power supply voltage suddenly changes from a low value to a high value, P ₁
Than resetting of is made of pulse width, erroneous detection can be prevented during rotation, a situation impedes such normal driving pulse P ₁ and the correction driving pulse P ₂ outgoing leave.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram according to the present invention. An oscillation circuit including a crystal oscillator, a frequency dividing circuit 2 for dividing a signal from the oscillation circuit 1, a waveform synthesizing circuit 3 for synthesizing a signal of the frequency dividing circuit 2 to generate a necessary pulse, and a waveform synthesizing circuit 3. And a power supply voltage detection circuit 80 for detecting the output voltage of the power supply 9 and a stepper motor 6 receiving the output from the drive circuit 5 and a control circuit 4a for timely outputting the signal to the drive circuit 5 and the rotation detection circuit 7. Is done. The output of the power supply voltage detection circuit 80 is connected to the control circuit 4a, the pulse width of the driving pulse P ₁ is controlled when the supply voltage varies. FIG. 6 is a signal synthesizing circuit for normal drive pulse control according to the present invention. 4bit terminal of 10 to 17 is a signal for determining the P ₁ pulse width. 11 is 10 inverted signal, 13 is 1
2,15 indicates 14, and 16 indicates 16 inverted signals. The pulse width of P ₁ by controlling the signal of the 4bit switch about
It can be set from 0.98msec to about 4.64msec every 0.244msec. The combinations are as shown in Table 1 below.

Table 1 is a P ₁ pulse of 16 types, any of the pulse train is selectable by controlling the switch.

The signal input to the terminal 49 is a signal delayed by about 62.5 msec from the rise of the drive pulse as shown in the timing chart of FIG. Terminal 48 receives a detection output signal when the power supply voltage exceeds a certain level. The signals of the terminals 48 and 49 and the output of the NAND gate 43 which determines the drive pulse width are input to the NAND gate 44. Output 47 of NAND gate 44
Is a signal for initializing P ₁ min and also a signal for changing the setting range of P ₁ max.

FIG. 8 shows a flowchart of the present invention. Here, n is an integer having a value of 0 to 6. A is a positive integer.
P ₀ = 2.0 msec, ΔP = 0.244 msec, and P ₂ = 7.8 msec. After starting in step 100, in step 101, 0 is input to N and n to initialize. In step 102, it is detected whether or not the state of FIG. 5A has changed to the state of b. This detection is the first
This is performed by the power supply voltage detection circuit 80 shown in FIG. If the power supply voltage changes from the state a in FIG. 5 to the state b, the process proceeds to step 103. In step 103, (0-A) is input to n. Since A is a positive integer, n is a negative value. The output of step 103 follows step 106. If the power supply voltage does not change from the state a in FIG. 5 to the state b in step 102, a step 105 checks whether the power supply voltage remains in the state a or the state b in step 105. If the power supply voltage is in the state shown in FIG. 5B, the process proceeds to step 104, and (nA) is entered in n. Step 104 follows step 106, step 105
When the power supply voltage is not in the state of b, the process directly proceeds to step 106. In step 106, the normal drive pulse P ₁
= P ₀ + n △ P. Step 10
At 7 the output is output to the motor drive circuit 5. After outputting a normal driving pulse P _1, detects the rotation of the rotor by the rotation detecting circuit 7 at step 108. When the rotor is assumed to be a non-rotating in step 108, and outputs the correction driving pulse P ₂ at step 109. In step 110, 1 is added to the content of n, and the process proceeds to step 111. If it is detected in step 108 that the rotor is rotating, step 111 is performed. In step 111, it is checked whether the content of N has become 320. If N is less than 320, 1 is added to the content of N in step 112, and step 1 is executed.
Return to 02. When N = 320 in step 111, the process proceeds to step 113, where the content of N is set to 0, and the content of n is decremented by 1. Thereafter, the process returns to step 102.

〔The invention's effect〕

As described above, according to the present invention, it detects a power supply voltage, by the height of the power supply voltage, since the normal driving pulse width P ₁ is variable can, it is possible to improve the reliability of the rotation detection of the rotor, The effect is enormous for electronic watches that aim to diversify power supplies.

[Brief description of the drawings]

FIG. 1 shows a block diagram according to the invention. Fig. 2
FIG. 3 is a waveform diagram showing an example of a conventional motor drive waveform.
It is a block diagram of the conventional correction drive system. FIG. 4 is an example of a flowchart of a conventional correction drive method. FIG. 5 is a diagram showing the relationship between the pulse width of the normal drive pulse and the coil induced voltage. 6 is a circuit diagram showing a signal combining circuit example for upper pulse width setting of the pulse width initialization and P ₁ according to the present invention. FIG. 7 is a timing chart of the input terminal portion of FIG. FIG. 8 is a flowchart of the present invention. DESCRIPTION OF SYMBOLS 1 ... Oscillation circuit, 2 ... Divider circuit 3 ... Waveform synthesis circuit, 4, 4 '... Control circuit 5 ... Drive circuit, 6 ... Step motor 7 ... Rotation detection circuit, 8 ... Circuit part 9 Power supply, 18 to 37 Switches 38 to 44 NAND gate 80 Power supply voltage detection circuit

Claims (3)

(57) [Claims] An oscillation circuit, a frequency division circuit for dividing a frequency of a signal from the oscillation circuit, a waveform synthesis circuit to which an output of the frequency division circuit is input, a normal drive pulse for driving a step motor, and a correction drive In an electronic timepiece having a drive circuit for outputting a pulse and a rotation detection circuit for detecting whether or not a step motor is rotated by application of a normal drive pulse, a power supply voltage is detected and a detection output signal is output when the power supply voltage changes. The generated power supply voltage detection circuit and, in response to the detection output signal, set the energy of the normal drive pulse to a value smaller than the energy of the normal drive pulse before the power supply voltage changes, thereby preventing malfunction of the rotation detection circuit. An electronic timepiece having a control circuit for performing the following. 2. The electronic timepiece according to claim 1, wherein said control circuit sets the energy of the normal drive pulse to a minimum settable value in response to said detection output signal. 3. The energy control of the normal driving pulse includes:
2. The electronic timepiece according to claim 1, wherein the electronic timepiece is controlled by a pulse width.