JPS61116682A - Electronic timepiece - Google Patents

Abstract

PURPOSE:To elevate the load resistance characteristic, impact resistance and stability, by a method wherein a drive coil is grounded at end thereof through a transistor low in the output resistance while being done at the other end thereof through a transistor high in the output resistance while no drive pulse is applied. CONSTITUTION:This electronic timepiece is made up of an oscillation circuit 115, a frequency dividing circuit 116, a pulse generation circuit 117, a pulse motor driving circuit 118 comprising a plurality of MOSFETs 218-223 to be controlled independently, a detection circuit 233 which detects an induced voltage to be generated in a drive coil after a drive pulse to a pulse motor is interrupted and the like. A drive coil 217 is connected between common drains (a) and (b) of MOSFETs 222 and 223 high in the output resistance while terminals (a) and (b) are connected o respective input gates of induced voltage detection inverters 225 and 224. Then, while no drive pulse is applied, the MOSFET 221 is OFF and the MOSFETs 220 and 223 are ON. The (a) terminal is grounded through the MOSFET 220 low in the output resistance while the (b) terminal is grounded through the MOSFET 223 high in the output resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive circuit for a Norse motor in an electronic timepiece, and an object of the present invention is to reduce the power consumption of a pulse motor and also to achieve high reliability.

Regarding the drive circuit of the pulse motor used for electronic watches, it is relatively narrow because low output is required during steady state.
The current consumption is reduced by using pulse-width drive pulses, and it can be used during abnormalities such as day-of-the-week feed loads and shock loads. A method has been proposed in which the pulse width is controlled by the induced voltage of the drive coil and set widely in steps to achieve high output.

However, in the above method, in order to detect the induced voltage in the drive coil, the drive coil is opened immediately after the drive pulse is cut off, so the braking force due to the induced voltage is not applied to the rotor of the main pulse motor. Therefore, malfunctions such as step feed due to unstable rotation are likely to occur, and since the induced voltage is directly applied to the input of the inverter for detection, it is difficult to drive according to the threshold voltage of the inverter. The disadvantage is that the number of turns of the coil must be set.

Furthermore, in the two-phase alternating drive pulse, the pulse width of one pulse of the next phase is controlled by the induced voltage immediately after the driving pulse of one phase is cut off, so when the induced voltage is near the threshold voltage, the pulse width There was also a drawback that the output was switched for each pulse, resulting in a malfunction if the required output could not be obtained.

The present invention provides a pulse motor drive circuit that does not have the above-mentioned drawbacks and has good load-bearing characteristics, good impact resistance, and high stability.

The present invention provides a pulse motor for a watch that is driven by a constant 2-pulse width drive pulse that is different during normal and abnormal times, and when the drive pulse is not applied, one end of the drive coil is connected to a transistor with low output resistance, etc. An object of the present invention is to provide a clock/main pulse motor drive circuit whose end is grounded via a transistor with high output resistance.

Further, the present invention provides a pulse motor for a watch that is driven by driving pulses with a constant pulse width of 2 pulses, which are different during normal times and abnormal times, and which, during abnormal times, supplies a pulse with a constant pulse width that lasts for a certain period of time and is different from that during normal times. An object of the present invention is to provide a pulse motor drive circuit characterized by the following.

Examples will be described below.

FIG. 1 shows an example of a pulse motor for a watch, and 101 is a rotor made of a magnet having at least two magnetic poles;
2. 103 is a stator made of magnetic material, 104 is a drive coil, and a and b are drive coil terminals, which fix the magnetic flux generated in the drive coil due to the current due to the two-phase pulse voltage applied to a and b. The rotor is rotated in a fixed direction in a stepwise manner. Moreover, FIG. 2 shows another embodiment of a 2-ruth motor for a watch.

FIG. 3 is a block diagram of an embodiment of a conventional pulse motor drive circuit for a watch, in which 110 is an oscillation circuit, 111 is a frequency dividing circuit,
112 is a pulse generation circuit, 113 is a drive circuit, 114
indicates a detection control circuit. FIG. 4 is a block diagram of an embodiment of the pulse motor drive circuit for a watch according to the present invention, in which 115 is an oscillation circuit, 116 is a frequency dividing circuit, 117 is a pulse generation circuit, 1
18 is a drive circuit, 119 is a detection control circuit, and 120 is a counting circuit. FIG. 5 shows a specific embodiment of the drive circuit of the present invention, FIG. 6 is an explanatory diagram of the state of the drive coil, FIG.
FIG. 8 is a waveform diagram of each part, FIG. 7 shows a steady state, FIG. 8 shows a state under load, and FIG. 9 shows another specific example of the drive circuit.

In FIG. 5, the flip 70 f of the frequency dividing circuit 116
(hereinafter referred to as FF) 208, 209 output is A? It is the input to the dirt circuit 211 of the pulse generation circuit 117, and the output of the F F 208 is the input to the pulse generation circuit 11 during normal operation.
7 F F 214.215 reset terminal R,, R,
Short pulses φ1 and φ2 each having a width of 2 pulses are generated alternately at the respective outputs Fl and F2. In addition, each output F, F2 is connected to the input of the OR circuit 227 of the detection control circuit 119, and the output thereof is connected to the S terminal of the beam Senotosenotoflinopfuronop (hereinafter referred to as R8-FF). . The other output F1 of F F 214 is F F 2
16 and the input of F F 216 of the control circuit 232 composed of AND circuits 212 and 213, and the drive circuit 118
At the input of the P-ahMOS transistor 218, F F
The output P2 of the F F 215 is connected to the other input of the F F 216 and the input of the P-ch MOs transistor 219 of the drive circuit 118, and the output F of the F F 216 is connected to the N-ch M
The output F3 is connected to each input of the Os transformer 220 and the AND circuit 212, and the output F3 is connected to the N-chMOS transformer 221. AN
It is connected to each input of the D circuit 213.

The other input of the AND circuit 212 of the control circuit 232 is F.
The output F0 of F210 is the output F0 to the other input of the AND circuit 213. is connected, and the output of the AND circuit 212 is N
The outputs of the -ch MOs transistor 223 and the AND circuit 213 are connected to each input of the N-ch MOs transistor 222. The drive coil 217 is connected between the common drains a and b of the MOS transistors, and the a terminal is connected to the induced voltage detection inverter 225 of the detection circuit 233, which is composed of induced voltage detection inverters 224 and 225 and transistors 222 and 223 with high output resistance. The b terminal is connected to each human power r-t of the induced voltage detection inverter 224, each output is connected to the input of the r-t circuit 226, and the dart circuit 2
The other inputs of FF26 are connected to the outputs F0 and Fo of FF210, and the output n is the reset terminal R of R8-FF228.
Connected to 4. In place of the transistors 222 and 223, which have high output resistance, a transistor 303 and 303, which has low resistance and operates as a switching element, is used as shown in FIG.
A series connection of 04 and high resistance 301, 302 may also be used. AND circuit 229 receives output F4 of R8-FF 228 and input φ of FF 210. is powered by two people, and the output j
is connected to the reset terminal R5 of R8-FF230, and is set to j=0 during normal operation. R8-FF 230
Set terminal S.

The output of the counting circuit 120 is connected to the output F, the reset terminal R6 is connected to the output F, and the outputs FM and F5 of R8-FF230 are connected to the input of the f-) circuit 211. Pulse generation circuit 117 according to the output
generates output pulses with different pulse widths.

In FIG. 7, 1 = 1. φI/41 pulse occurs, the P-ah MOS transistor 218 in the drive circuit 118 in FIG. 5 is turned on, and the N-ch MOS
) Since the transistor 221 is on, the
) A drive voltage is applied to the drive coil a terminal, a current flows from a to b, the stators 102 and 103 are excited, and the rotor 101 rotates 180° clockwise, vibrates for a certain period of time, and then stops. Immediately after the drive pulse ends at 1 = 12, N
-chMOs transistor 221 is turned off, and N-a
hMOS trannostar 220 and high output resistance N-
chMOS transistor 223 (equivalent resistance is r)
When it is off, the a terminal is directly grounded and the b terminal is grounded through the resistor r, as shown in FIG. 6(2).

The induced voltage caused by the rotation of the rotor is divided and applied to the detection inverter 224 of the detection circuit 233, so that L=1.
~At t4, the induced voltage exceeds the threshold voltage of the inverter! IM”-to circuit output n is generated. 1= due to φ1
1. The output i of R8-FF288 which is set to l is reset to e-) pt=t by the circuit output n, and i=0 by the circuit output n. Therefore, the AND circuit output j=o, and the output F of R8-F'F230 is 1, F.

=O, and the r-to circuit 211 sends the high frequency divided output to the Noculus generating circuit 117's F F 214.2.
Since the driving pulse width is applied to each of the reset terminals R, R2 at an angle of 15 degrees, the width of the driving pulse is set narrow.

Then 1 = 1. φ2/# rus occurs, and P-chM
Os transistor 219 is on, N-ch MOs
Since the transistor 220 is on, FIG.
As shown in 3), a driving voltage is applied to the b terminal of the driving coil, a current flows from b to a, the stators 102 and 103 are excited in the opposite direction, and the rotor rotates 180 degrees clockwise again. It vibrates for a certain period of time and then stops. 1=1. The N-ah M OS transistor 220 is turned off immediately after the drive non-current is cut off, and the N-ah M OS transistor 221 is turned off.
, and N-ah MOS with high output resistance) is turned on, and the b terminal is grounded directly and the a terminal is grounded through the resistor r, as shown in Fig. 6 (
4) It will look like this. The induced voltage accompanying the rotation of the rotor is divided and applied to the detection input of the detection circuit 233 and the bark 225, and when the induced voltage exceeds the threshold voltage of the inverter from 1 = 17 to t8, the by-to circuit outputs. occurs, and the following is the same as before, and the 1,000 rus width is set narrow. In other words, if the induced voltage of the drive coil is higher than the threshold voltage of the detection inverter under no-load condition during steady state,
The pulse width is set narrowly, and the drive coil is closed circuit through the equivalent resistance r while the drive/2 pulse is not applied, and the braking current flows due to the induced voltage, which stabilizes the operation of the rotor. Significantly improved. If the induced voltage in the drive coil immediately after the drive pulse is cut off is V, and the drive coil resistance is R, the voltage applied to the detection inverter is rv/(R+
r), it is possible to match the threshold voltage of the detection inverter by changing the equivalent resistance r. Let's consider a case where an abnormal state occurs due to a load. In Figure 8, initially it is normal and 1 = 1. ,~1. A narrow drive/malus is applied to the drive coil at □, 1 = 1. ,~t
Detection inverter output is generated at 14. When a load is applied in this state, the angular velocity of the rotor decreases and 1 =
The induced voltage after 1.5 must be below the threshold voltage of the detection inverter, 1 = 1. j output occurs, and R
8-FF230 F, = 0, F, = 1 is reset,
The r-t circuit 211 switches, and the low frequency divided output is sent to the Nors generation circuit 117's F F 214, R of 215,...
The width of the drive pulse applied to R2 increases stepwise.

- The reset of the force counting circuit 120 is released and starts counting the number of drive pulses. For example, if the pulse counting circuit is set to the number of pulses required to feed the day of the week, the width of the drive pulse will become wider as the day of the week feed starts, and a count output will be generated after the day of the week feed is finished and set to the S terminal of R8-FF230. A pulse is applied,F,=1,F.

= 0, the counting circuit 120 is reset to
The output circuit 211 can be switched back to a no-load condition with a narrow pulse width.

If configured as in the present application, during normal operation, the converter is driven with a drive pulse with a minimum pulse width of 5 mm or less necessary for driving the converter,
By setting the pulse width to 5 mm or more during a certain period of time, including the period when the day of the week feed load is applied, the converter is given driving force that can withstand the load and prevents malfunction, thereby reducing the average current consumption to 1 μA or less. It is possible to reduce it to

Furthermore, when the application of the drive pulse ends, the drive coil becomes a closed circuit via a low resistance transistor and a high resistance transistor, or a low resistance transistor and a high resistance as shown in Figure 9, and a braking current due to the induced voltage flows. The operation of the rotor is extremely stable, and malfunctions such as 2-stenog feed can be prevented.

The voltage applied to the detection inverter is the equivalent resistance r of a transistor with a high output resistance, or the high resistance 301 shown in FIG.
Since the threshold voltage of the inverter can be easily adjusted by changing the value of 302, there is also the advantage that there is no need to change the basic specifications such as the magnetic moment of the rotor of the pulse motor and the number of turns of the drive coil.

In this embodiment, a transistor with high output resistance is used, but as shown in FIG.
04 and high resistance 301.302 may be used. It is also possible to use capacitors instead of resistors, in which case energy storage is possible.

Furthermore, since the induced voltage of the drive coil is detected by a CMOS inverter, there is an advantage that there is no need for a detection mechanism such as providing a detection coil in the converter or providing a contact or a semiconductor in the wheel train connected to the converter. There is. In this embodiment, the width of the driving nozzle is set to be twice as large as that during normal operation when there is an abnormality, but it is also possible to set the drive nozzle width to an arbitrary or somewhat arbitrary width in steps.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of one embodiment of a pulse motor for a watch, Fig. 2 is an explanatory diagram of another embodiment, Fig. 3 is a block diagram of an embodiment of a conventional pulse motor drive circuit for a watch, and Fig. 4 is an explanatory diagram of an embodiment of a pulse motor for a watch. is a block diagram of an embodiment of the pulse motor drive circuit for a watch according to the present invention, FIG. 5 is a circuit diagram showing a specific embodiment of the drive circuit of the present invention, and FIGS. 6 (1), (2) ( 3) and (4) are state explanatory diagrams of the drive coil, FIGS. 7 and 8 are waveform diagrams of various parts, and FIG. 9 is a partial circuit diagram showing another specific example of the drive circuit. 112.117...-a4 pulse generation circuit 113.
・・・・・・・・・・・・・・・Drive circuit 114.119
...Detection control circuit 120...
...Counting circuit 218.219...P-ch
MOs Tranostar 220, 221, 222, 223
−=・N−c hMO8 transistor 224.22
5...Detection inverter 301.302...
...High resistance 232... Control circuit 233
・・・・・・・・・・・・Detection circuit Fig. 1 Fig. 2 Fig. 3 Fig. 9 Fig. 7

Claims (1)

[Claims] Oscillator circuit, frequency divider circuit, multiple MOs each controlled independently
A pulse motor drive circuit consisting of an S transistor, a pulse motor including a drive coil and a rotor, a detection circuit that detects an induced voltage generated in the drive coil after cutting off a drive pulse to the pulse motor, and a detection circuit that detects an induced voltage generated in the drive coil after cutting off a drive pulse to the pulse motor, and output pulses with different pulse widths. In an electronic timepiece that is controlled by a pulse generation circuit that generates a pulse, and that is controlled by the detection circuit and supplies an output pulse having a large pulse width from the pulse generation circuit to the pulse motor drive circuit, the detection circuit includes a drive coil that constitutes the pulse motor drive circuit. a series circuit of a high resistor and a switching element connected in parallel to at least one of a pair of MOS transistors connected to the same potential line from both ends of the resistor, and a detection element for detecting the induced voltage generated in the high resistor. the switching element and the pair of MOs;
A control signal for switching exclusively with the switching element is supplied to the MOS transistor on the side to which the switching element is connected to the control terminal of the S transistor, and
An electronic timepiece characterized in that the other MOS transistor is supplied with a control signal for switching simultaneously with the switching element.