JPS5934986B2 - Clock drive circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circuit used for driving a timepiece transducer, particularly an electromagnetic transducer.

In electronic watches whose allowable power consumption is particularly small and limited, electromagnetic conversion is often used as the energy conversion mechanism because it is highly efficient.

For example, a wall clock,
Manganese batteries are usually used in table clocks and the like due to cost considerations. However, manganese batteries do not have good discharge voltage characteristics, and to compensate for this, circuit systems that are insensitive to battery voltage fluctuations have been developed. As an example, 15 types shown in FIG. 1 have been proposed. This method uses a detection coil that generates an induced voltage by the magnetism of a magnet installed in a vibrating body such as cannabis; Twenty constant voltage circuits such as T2 are provided. However, this method also has the following drawbacks. (1) Temperature characteristics, that is, battery voltage vs. output voltage characteristics and signal input current vs. output voltage characteristics, are both susceptible to the influence of ambient temperature, so in the case of a 25-year high temperature, the amplitude will fluctuate, etc. It has a negative impact on time. (2) The slope of the signal input current vs. output voltage characteristic is steep, and there is no saturation region in the usage region, so the output voltage fluctuates greatly depending on the magnitude of the signal input current.

(3) The driving transistor Ti requires a sufficiently large DC current amplification factor (e.g. 400 to 600) in order to reduce the collector-emitter saturation voltage. process is required.

(4) Since the coil-magnet amplification effect is used, in order for the transistor Tl to start, the induced voltage generated in the Woo detection coil SC must have a voltage value equal to or higher than the base-emitter threshold voltage. Because of this, especially when the battery voltage approaches the output voltage, that is, when the battery voltage decreases, starting performance deteriorates.

The object of the invention is to overcome the above-mentioned drawbacks.

The configuration of the present invention will be described with reference to FIG.

The system of the present invention can be roughly divided into a detector 1 and an amplifier 2.
, output voltage generator 3, controller 4, battery B1 drive coil D
It starts with C. The detector 1 consists of a detection coil SC1, a capacitor C1, and a capacitor C, and detects the magnetism of Tianfu having a permanent magnet (not shown).
A signal input is given to an amplifier 2 which will be described later. The amplifier 2 has transistors Q, , transistor Q, transistor Q3, resistors R, and resistors R, and transistors Q,
is of npn type and its base is biased by resistor R1, transistor Q, is of pnp type and its base is coupled to the collector of transistor Q, via resistor R, and transistor Q3 is of npn type and its base is biased by resistor R1. The emitter of transistor Q1 is coupled to the collector of transistor Q, and the emitter of transistor Q is coupled to the anode of battery B. The emitter of transistor Q1 and the emitter of transistor Q are coupled to the cathode of battery B. The output voltage generator 3 has a diode Di1 transistor Q4, a transistor Q5, a resistor R, a resistor R4, a resistor R, and a resistor R6, and the diode Di and the resistor R are connected to the anode of the battery B and the transistor Q,
The anode of the diode Di is coupled to the base of the transistor Q4, the collector of the transistor Q4 is coupled to the base of the transistor Q, and to the anode of the battery B via the resistor R4. The emitter of Q4 is coupled to the collector of the transistor Q3 via a resistor R, and the collector of the transistor Q is coupled to the anode of the battery B0) via a resistor R6 and the base of a transistor Q6 of a controller 4, which will be described later. The emitter of transistor Q5 is coupled to the collector of transistor Q3. Controller 4 is transistor Q6
, a transistor Q7, the emitter of transistor Q6 is coupled to the anode of battery B, the collector of transistor Q, is coupled to the base of transistor Q7, the collector of transistor Q7 is coupled to the base of transistor Q1, transistor Q7 The emitter of is coupled to the cathode of battery B. The drive coil DC is coupled between the anode of battery B and the collector of transistor Q3 of amplifier 2. A capacitor C is connected between the base and collector of the transistor Q3 of the amplifier 2 to prevent abnormal oscillation. A capacitor C is also connected between the collector of the transistor Q3 and the base of the transistor Q1 to prevent abnormal oscillation. Next, the effect will be explained.
The electric signal induced by the detection coil SC is transferred to the capacitor C1.
It becomes an input to the transistor Q1 through the transistor Q1, and is amplified by the transistor Q1, transistor Q, and transistor Q3. With the amplified signal current, the drive coil DC drives a base having a permanent magnet (not shown). In order to eliminate the influence of voltage fluctuations of battery B, it is sufficient to keep the voltage supplied to the drive coil DC constant regardless of voltage fluctuations of battery B, but the present invention further improves the temperature characteristics as described above. It is something. That is, a reference voltage VP1 is created by a series circuit of a diode Di and a resistor R3, and this is supplied to the base of the transistor Q.
4. A temperature-compensated output voltage is created by the transistor Q, the resistor R, and the resistor R6.

To explain the operating principle of this output voltage generator 3, if the forward voltage of the diode Di is F1, the voltage between the base and emitter of the transistor Q4 is D, and the voltage between the base and emitter of the transistor Q is BE, then Output voltage Vs
is expressed by the following equation (1), and is constant regardless of the voltage of battery B as long as the voltage of battery B is greater than or equal to the sum of Vs and the collector-emitter voltage of transistor Q3. However, ΔV
BE=VF, -VF Next, the temperature characteristics of the reference voltage Vs will be described.

Assuming that the current flowing through the resistor R is 13 and the current flowing through the resistor R is 14, and if 13 is made larger than 14, then from the current dependence of the temperature coefficient of the diode Dif) forward voltage shown in Figure 3, Δ■BE has a positive temperature coefficient and VB
E will have a negative temperature coefficient. Therefore, by selecting an appropriate value for the resistance value ratio, it is possible to make the temperature coefficient of the reference voltage s substantially zero. Next, the effect of keeping the output voltage constant with respect to the magnitude of the input signal current will be explained.

Naturally, when no signal input current flows into the base of transistor Q1, amplifier 2 must be in a cut-off state. However, when the signal input current increases beyond a certain limit, the collector currents of each of transistors Q1, Q, and Q3 increase, resulting in an increase in the output voltage Vs. However, since VF, is held at a constant value by the diode Di, the collector current of the transistor Q4 is kept almost constant, and the resistor R
Although the voltage drop across resistor R4 is also approximately constant, as described above, as the output voltage ■s increases, the base current of transistor Q5 increases, and the amount of voltage drop across resistor R8 increases. Then, the collector current of transistor Q6 increases, and the base current of transistor Q7 increases, so transistor Q1
A portion of the signal input current flowing through the base of transistor Q7 becomes current 12 and is shunted through the collector of transistor Q7. As a result, the current 11 is kept constant and an increase in Vs can be suppressed. Thus, according to the present invention, the output voltage can be controlled very well against fluctuations in the voltage of battery B.

An example of this is shown in FIG. 4. In this example, if the battery voltage is 1.2■ or more, the output voltage is stably maintained at 1.1■. The temperature characteristic was improved as shown in FIG. 5, and the temperature characteristic of the present invention was -0.1 mV/°C, whereas it was -2.5 m/°C in the conventional method. FIG. 6 shows the fluctuation of the output voltage with respect to the fluctuation of the signal input current. In the area where the conventional method is used, the slope is extremely steep and a large signal input current is required. On the other hand, the amplifier of the present invention has a high gain due to the combination of transistors Q1, Q2, and Q3, and the controller has a high gain due to the complementary connection of transistors Q6 and Q7. As shown in Fig. 6, the output voltage enters the operating range from a minute signal input current and is flat over a wide range in the operating range.

In addition, in the conventional method, the drive transistor T, has a collector
Since a sufficiently large DC amplification factor is required to reduce the emitter-to-emitter saturation voltage, monolithic I
C requires a special process, but the present invention is constructed by connecting three transistors of npn type, p-type, and npn type in series, so that the DC amplification factor can be sufficiently satisfied with normal processes. is obtained.

Furthermore, the present invention has a large current gain, and the detection coil S
Even if no voltage is induced in C, the transistor Q2 in FIG.
If there is a voltage higher than the base-emitter voltage of the transistor Q4, the transistor Q4 will be saturated, so it has excellent starting performance.

When the circuit system of the present invention is applied to, for example, a wrist-driven electronic timepiece, the following effects can be obtained.

That is, as shown in FIG. 7 over a wide temperature range, there is no change in the amplitude due to changes in battery voltage, so extremely good isochronism can be obtained until near the end of the battery life. Conventionally, as a device for adjusting the swing width of the crown, for example, an eddy current brake was installed near the center of the swing width to limit the swing speed, but the circuit system of the present invention eliminates the need for such a device and its fine adjustment work. Therefore, losses due to eddy current braking are completely eliminated. As a result, battery life has been extended to about twice that of conventional batteries. In the above, the present invention has been described with reference to the case where the present invention is applied to a trumpet, but it can be similarly applied to a sound piece, a sound piece, a pendulum, a transistor motor, etc.

Although the detector 1 is described as using a detection coil SC, this portion may be any other device capable of detecting magnetism, or a photoelectric conversion device may also be used. Diode Di does not necessarily have to be a diode,
Other devices having characteristics as shown in FIG. 3 may also be used.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a conventional watch drive circuit, FIG. 2 is a diagram showing an example of a circuit according to the present invention, and FIG. 3 is a diagram showing the relationship between forward current of a diode and forward voltage temperature coefficient. Fourth
The figure shows the relationship between the battery voltage and the output voltage of the circuit according to the present invention, FIG. 5 also shows the relationship of the output voltage with respect to temperature change, and FIG. 6 shows the relationship between the signal input current and the output voltage. , FIG. 7 is a diagram showing the relationship between battery voltage, isochronism, and tilt angle. 1...detector, 2...amplifier, 3...
...Output voltage generator, 4...Controller, B.
...Battery, SC...Detection coil, DC
...Drive coil, R3...Bias resistance, R,, R5, R6...Resistance, Di...
・Diode, Q4...first transistor,
Q5...Second transistor.

Claims (1)

[Claims] 1 In the drive circuit of an electromagnetic transducer for watches, there is a detector that detects the amplitude of the vibrating body, an amplifier that is connected to a power source and inputs the detection signal of the detector, and a drive coil that is connected to the output terminal of the amplifier. The collector and emitter are connected to the output terminal of the amplifier through a resistor with an appropriate ratio, and the base is connected through a bias resistor, and a diode or a device with similar characteristics is connected between the base and emitter connected resistors. A clamped first transistor and a second transistor whose collectors are connected to the output terminal of the amplifier through a resistor and whose emitters are connected directly to each other and whose bases are connected to the collector of the first transistor are arranged so that the voltage applied to the drive coil is controlled by the temperature. A clock drive having an output voltage generator to compensate and hold constant, and a controller actuated by the collector voltage of the second transistor to shunt the amplifier input current so as to keep the voltage of the drive coil constant. circuit.