JPS6152956B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a high voltage generating circuit built into an electronic watch powered by a battery. Batteries used in electronic watches generally have an output voltage of 1.5 volts to 3.0 volts, and when using circuit elements that require a relatively high voltage, the voltage of the built-in battery is converted by a voltage conversion circuit. Boost the pressure,
It is necessary to drive the circuit elements. For example, the driving voltage of a sounding device that uses piezoelectric ceramics, etc.
A high voltage generating circuit is an essential element in obtaining a driving voltage for an electroluminescent device used as a lighting means for a display device. Hitherto, various high-voltage voltage generating circuits that satisfy these purposes have been proposed and put into practical use, but each of these circuits is required for each purpose. For this reason, separate high-voltage voltage sources are required for two or more different purposes, or circuit elements that require multiple different high-voltage voltages are used even for the same purpose. In order to operate the watch, it was necessary to incorporate multiple high voltage generation circuits corresponding to each voltage level into the watch. This not only increases the number of parts and is uneconomical, but also requires the abandonment of functions when components must be housed in a small space, such as in an electronic wristwatch.

The purpose of the present invention is to convert the output voltage of a battery with an electromotive force of 1.5 volts to 3.0 volts built into an electronic watch into two high voltages with opposite polarities using a simpler and more economical circuit with fewer parts. It lies in creating. The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a circuit diagram showing the most basic configuration of the present invention. _T1 is a PNP transistor and operates as a first switching element, and _T2 is an NPN transistor and operates as a second switching element. A coil L having a magnetic core is connected between the collectors of the two transistors _T1 and _T2 ,
The connection points are provided with output terminals P ₃ and P ₄ , respectively. One ends of resistors R ₁ and R _{2 are connected to the bases of the two transistors T 1 and T 2 , respectively, and the other ends of the resistors R 1 and R 2 become} input terminals P ₁ and P _2, respectively. ing. The emitter of the first transistor _T1 is connected to the power line _VHH , and the emitter of the second transistor _T2 is connected to the power line GND, which is a potential reference. Although not shown, the power supply line V _HH is connected to the + side of the built-in battery of the watch, and the output voltage V (volts) of the battery is applied thereto. Further, it is assumed that the power supply line GND is connected to the negative side of the built-in battery, and its potential is 0 (volt). In such a circuit configuration, a high voltage can be generated at the output terminal P ₃ or P ₄ by applying an appropriate control signal voltage to the input terminals P ₁ and P ₂ . This will be explained using the voltage waveform shown in FIG. Waveforms A, B, C, and D in Figure 2 are input terminals P 1 and ₂ of the circuit diagram in Figure 1, respectively.
This is the input/output voltage waveform of P ₂ and output terminals P ₃ and P ₄ .
In Fig. 2, in time zone A, input terminals P ₁ and P ₂
The potential of is V (volt), which is equal to the power supply line V _HH , and at this time, the transistor T ₁ is in a cut-off state,
Transistor _T2 is also in the cutoff state. Coil L
Both ends of the output terminals P ₃ and P ₄ are disconnected from the power supply lines V _HH and GND, and the potentials of the output terminals P 3 and P 4 are undefined between 0 (volts) and V (volts). In time zone B, the potential of the input terminal _P2 is V (volt), and the transistor _T2 is in a conductive state. Therefore, the potential of the output terminal _P4 is approximately 0 (volt). At the same time period B, the potential of input terminal _P1 is 0 (volt) and V
(volts) and the transistor T ₁ repeats rapid transitions between the conductive state and the cut-off state. At this time, current is supplied and cut off to the coil L, but when the current is cut off, the back electromotive force of the coil L ( _-VouT ) is induced. This voltage has a negative polarity and its peak magnitude can reach over a hundred volts. On the other hand, in time period C, the potential of input terminal _P1 is 0 (volt)
, and transistor _T1 is in a conductive state. Therefore, the potential of the output terminal _P3 is approximately V (volt). In the same time period B, the potential of input terminal _P2 is V
(volts) and 0 (volts), the transistor T ₂ repeats rapid transitions between the conductive state and the cut-off state. At this time as well, current is supplied and cut off to the coil L, but when the current is cut off _, the back electromotive force of the coil L (+V
_OUT ) is induced. This voltage has a positive polarity and its magnitude also reaches more than 100 volts. As explained above, the battery voltage is applied to one coil through two transistors, and by appropriately controlling conduction or cutoff of the transistor, a positive or negative high voltage is applied to both ends of the coil. However, this transistor is used as a current switching means and may be replaced with other switching means.
Reed relays, SCRs, etc. are suitable as such switching means. In addition, in the circuit shown in Fig. 1, the transistor _T1 is a PNP transistor, and the transistor _T2 is an NPN transistor, and both are connected as a collector follower. However, the transistor _T1 is an NPN transistor, and the transistor is connected as an emitter follower. Also good. Of course, transistor _T2 may be similarly connected as a PNP transistor and emitter follower connected, transistor _T1 may be an NPN transistor, and transistor _T2 may be connected as an emitter follower.
A PNP transistor may be used, and both transistors may be connected as emitter followers. However, no matter what kind of switching means is used, it is necessary to control so that one switching means is turned on while the other switching means is changed from a conductive state to a cutoff state. When using bipolar transistors here, considering the transistor's withstand voltage conditions and the magnitude of the voltage that can be applied to the coil, it is recommended to use two transistors in a collector-follower connection as shown in the circuit diagram in Figure 1. desirable.

The basic operation of the present invention has been explained above with reference to FIGS. 1 and 2, and next, a more detailed explanation of the present invention will be given regarding a more specific application example.

FIG. 3 is a circuit diagram of a DC dual power supply generating circuit provided for supplying power to an operational amplifier built into an electronic timepiece, and is a specific embodiment of the present invention. In order to properly operate an operational amplifier, two power supplies, positive and negative, are required relative to the reference potential of the device, and in order to sufficiently increase the voltage amplitude of the signal to be handled, it is necessary to increase the voltage of the power supply. . The present invention is extremely useful in meeting such requirements for power supplies. In FIG. 3, numeral 1 is a control signal generating circuit, and numeral 2 is a positive and negative direct current dual power source generating circuit for an operational amplifier using the high voltage generating circuit of the present invention. The emitter of the PNP transistor _T1 provided as the first switching element is connected to the power supply line _VHH , and although not shown, is connected to the + side of the built-in watch battery, and the output voltage V (volts) of the battery. is applied. The emitter of the NPN transistor _T2 provided as a second switching element is connected to one side of the battery via the power supply line GND, and its potential is 0 (volts).
It is. A series circuit of a coil L with a magnetic core and a resistor R ₃ and a resistor R ₄ are connected between the collectors of the two transistors T ₁ and T ₂ . Further, the cathode of a rectifying current _D1 is connected to the collector of the transistor _T1 , and _the anode of a rectifier _D2 is connected to the collector of the transistor T2. A capacitor C _{1 is connected between the anode of the rectifier D 1} and the power line GND, and a capacitor C ₁ is connected between the anode of the rectifier D ₁ and the power line GND.
A capacitor _C2 is connected between GND.
The connection point between the anode of rectifier D ₁ and capacitor C ₁ is the negative voltage output terminal (V _-- ), and the connection point between the cathode of rectifier D ₂ and capacitor C ₂ is the positive voltage output terminal (V ₊₊ ). be. On the other hand, for the bases of the two transistors T ₁ and T ₂ there is a resistor R ₁ respectively.
The outputs of a NOR gate (NOR) and an OR gate (OR) are applied through R2 and _R2 . One input of the NOR gate (NOR) is a flip-flop circuit
It is connected to the output terminal Q of the FF, and the other input is connected to the signal terminal P. One input of the OR gate (OR) is connected to the output terminal of the flip-flop circuit FF, and the other input is connected to the signal input terminal P. The input terminal Cl of the flip-flop circuit FF is connected to the signal input terminal P. The flip-flop circuit FF divides the frequency of the signal applied to the input terminal Cl into 1/2 and outputs it to the terminals Q and 1/2. Note that the signals at terminal Q and terminal Q have a logically complementary relationship. Flip-flop circuit FF, gate NOR
A control signal generating circuit 1 consisting of a clock and an OR, and resistors R ₁ and R ₂ is incorporated in a part of a clock integrated circuit having a clock function, and the integrated circuit is powered by the clock built-in battery. It is assumed that Therefore, its signal level is 0 (volt) or V (volt) and can directly drive the two transistors T ₁ and T ₂ . In this configuration, when a rectangular wave signal is applied to the input terminal P, positive and negative voltages are output to the output terminals (V _-- ) and (V ₊₊ ), respectively. This will be explained according to the waveforms in Figure 4. In Figure 4, A shows the input signal waveform of input terminal P, B shows the output waveform of the NOR gate (NOR), and C shows the OR gate (OR).
The output waveform of is shown. That is, in the control signal generation circuit 1 shown in FIG. 3, two transistors are activated in synchronization with the signal waveform applied to the input terminal P.
A signal is generated that alternately turns off T ₁ and T ₂ . In time period t ₁ in FIG. 4, the two transistors T ₁ and T ₂ are in a conductive state, and the coil L and the resistor
A voltage approximately equal to the battery voltage V (volts) is applied to the series circuit of _R3 . At this time, the current i (ampere) of the coil L is expressed as follows: t (seconds) is the time period, _t1 is the elapsed time, _γ3 (ohm) is the resistance value of the resistor _R3 ,
It is given by the following equation, where γ (ohm) is the internal resistance of the coil L, and L (Henry) is the inductance of the coil L. where two transistors T ₁ and T ₂
It is assumed that the DC amplification factor of is sufficiently large and the collector-emitter saturation voltage is sufficiently small.

When the time t is sufficiently large or when the magnetic flux of the magnetic core of the coil L is saturated, the current i (ampere) is given by the following equation.

i = V / γ ₃ + γ ...(2) Coil L stores energy roughly proportional to the coil current, but when the magnetic flux of the magnetic core is saturated, the energy stored in the coil increases the current. It doesn't get bigger. In other words, since anything greater than the core saturation current i _sat is wasted, the resistor R ₃ must be appropriately selected so that both sides of equation (2) are equal to the core saturation current i _sat .

Next, in time period t ₂ , transistor T ₂ enters a cut-off state, and a back electromotive force is generated in coil L. This back electromotive force generates a current in the closed circuit of coil L, resistor R ₃ and resistor R ₄ , but transistor T ₂
Since the current immediately after the interruption of is equal to that given by equation (1) or (2) above, the following peak is created between the terminals P ₃ and P ₄ of the series circuit of coil L and resistor R ₃ . The value voltage V _OUT is obtained. Here γ ₄ (ohm) is the resistance
This is the resistance value of _R4 .

Or V _put = γ ₄ / γ ₃ + γV ...(4) At this time, the potential of terminal P ₃ is equal to the power line V _HH and V
(volt), the potential of terminal P ₄ is +V _put +
It becomes V (volt). After reaching the peak value, the potential at the terminal P ₄ decays exponentially with a time constant of L/γ ₃ +γ ₄ +γ (seconds), and asymptotically approaches the potential V (volts) of the power supply line V _HH .
This voltage waveform is shown in FIG. 4E.

In time period t ₃ , the two transistors T ₁
and T ₂ become conductive, current flows through the coil L, and magnetic energy is accumulated in the magnetic core, but this process is exactly the same as in time period t ₁ .

In time period _t4 , the transistor _T1 is cut off, and a back electromotive force is generated in the coil L. The magnitude of this back electromotive force is equal to that generated during time period _t2 . The potential of terminal _P4 is equal to the power supply line GND and is 0
(volt), the potential of terminal P ₃ is -V _put
It decays exponentially from the peak value of (volts) with a time constant of L/γ ₃ + γ ₄ + γ (seconds), and the potential of the power supply line GND becomes 0.
(volt). This voltage waveform is shown in FIG.

In this way, peak voltages are generated alternately at terminals P ₃ and P ₄ , but the respective peak voltages are rectified by rectifiers D ₁ and D ₂ , and capacitor C ₁
and C ₂ , negative and positive voltages are obtained at the output terminals (V _-- ) and (V ₊₊ ), respectively. The DC voltage at the output terminal (V _-- ) is approximately −V _put
(volts), and the DC voltage at the output terminal (V ₊₊ ) is V + V _put (volts), but as stated above, the magnitude of that voltage is determined by the resistance value ratio of resistor R ₃ and resistor R ₄ . Depending on the selection, it can be determined from equation (3) or equation (4).

FIG. 5 is a block diagram showing the configuration of an electronic timepiece with a heart rate measuring device including the DC dual power source generating circuit shown in FIGS. 3 and 4, and is one of the applied examples of the present invention. In the drawings, numeral 1 is a control signal generation circuit shown in the circuit of FIG. 3, and numeral 2 is a dual DC power supply generation circuit 2 also shown in FIG. The DC dual power supply generating circuit 1 includes an amplifier 13 incorporating an operational amplifier.
The amplifier 13 amplifies the output signal of the sensor 12 that detects the pulse and transmits the pulse signal to the pulse rate counting circuit 7. The sensor for detecting the pulse is realized by a strain gauge or a piezoelectric element. The pulse rate counting circuit 7 receives the time reference signal 3b from the oscillation frequency dividing circuit 3, measures the period of the pulse signal, processes the data, and displays the heart rate per minute on the display device 14 via the display drive circuit 5. Display as . On the other hand, the oscillation frequency dividing circuit 3 oscillates at the reference frequency given by the crystal oscillator 10, generates a reference frequency signal, and divides the frequency of the reference frequency signal to generate a necessary timing signal. One of the timing signals is the input signal 3a of the control signal generation circuit 1, and the other is the time reference signal 3b of the pulse rate counting circuit 7. The oscillation frequency divider circuit 3 also provides a time reference signal 3c to the clock circuit 4. The clock circuit 4 is central to the clock function, and receives the time reference signal 3c, integrates the time, holds the result as time information, and displays the time on the display device 14 via the display drive circuit 5. conduct. . The control circuit 6 receives input from the switch group 9 and controls the entire timepiece system. That is, by a specific operation of the switch group 9, the signal 6a is output and the output signal 3a of the oscillation frequency dividing circuit 3 is
, and starts and stops the operation of the control signal generation circuit 1 and the DC dual power supply generation circuit 2. Further, by other specific operations of the switch group 9, the operation control signal 6b of the pulse rate counting circuit 7 is output, the signal 6c for correcting the time information held by the clock circuit 4 is output, and the information displayed by the display drive circuit 5 is output. It outputs a signal 6d for selection and switching. The control circuit 6, oscillation frequency dividing circuit 3, time measurement circuit 4, display drive circuit 5, pulse rate counting circuit 7, and control signal generation circuit 1 are composed of one C-
It is formed on a MOS integrated circuit 11. battery 8
The power is supplied to the C-MOS integrated circuit 11 and the dual DC power generation circuit 2, and the output power of the dual DC power generation circuit is supplied to the amplifier 13. In such a configuration, when the switch group 9 is operated in a certain manner, the control signal generation circuit 1 and the DC dual power supply generation circuit 2 start operating, and power supply starts to the amplifier 13, making it possible to detect the pulse. Then, the heart rate is measured.

The detailed explanation of the present invention has been given above with reference to an example of an electronic watch with a heart rate measuring device, and this has been made possible by the following advantages of the present invention. First, the power supply circuit has become extremely compact because it is possible to generate two power sources, positive and negative, with one coil. Second, since it is easy to start and stop the operation of the DC power generation circuit as needed, the idling current of elements that require a high voltage power supply and the power generation circuit itself can be reduced to approximately zero, reducing consumption. You can save electricity. Thirdly, the output voltage of the DC power generation circuit can be determined to any value by simply selecting the resistance value, as shown by the above equation (3) or (4). Fourthly, since it has a small number of components and is implemented using only highly reliable circuit elements, it is economically rational with fewer failures. Fifth, since the operating voltage of the operational amplifier can be increased, the S/N ratio of the amplifier can be improved.

The present invention makes it possible to use an operational amplifier that requires two positive and negative power supplies, which greatly facilitates the handling of analog signals in electronic watches, which can be used in a variety of fields of application. In addition to the above-mentioned electronic watches with heart rate measuring devices, amplification of minute analog signals is necessary to realize wristwatches with built-in blood pressure monitors, electronic watches with built-in electronic barometers, electronic thermometers, testers, etc. I was able to solve that problem.

[Brief explanation of the drawing]

1 and 3 are circuit diagrams of the high voltage generation circuit of the present invention, and FIGS. 2 and 4 A to 4 are time charts of voltage waveforms showing the operation of the circuits of FIGS. 1 and 3, respectively. FIG. 5 is a block diagram showing an example in which the circuit of FIG. 3 is applied to an electronic timepiece. T ₁ ... PNP transistor, T ₂ ... NPN transistor, L ... Coil with magnetic core, R ₁ , R ₂ , R ₃ , R ₄
...Resistor, C ₁ , C ₂ ... Capacitor, D ₁ , D ₂ ...
... Rectifier, 1 ... Control signal generation circuit, 2 ... DC dual power supply generation circuit, 4 ... Timing circuit, 8 ... Battery,
14...Display device.

Claims (1)

[Claims] 1. In an electronic watch that includes at least a battery, an oscillation frequency dividing circuit and a timekeeping circuit using the battery as a power source, and a display device driven by the output of the timekeeping circuit, a coil is provided at each end of the coil. It has two switching elements connected to each other, and is configured so that power from the battery is supplied to the coil via the two switching elements, and the first switching element is made to conduct DC while the second switching element is connected. A positive high voltage is obtained by transitioning the switching element from the conductive state to the open state, and a negative high voltage is obtained by transitioning the first switching element to the conductive state while making the second switching element conductive. A voltage booster for an electronic timepiece, which is operated by applying the positive or negative high voltage to the oscillation frequency dividing circuit, a timekeeping circuit, a display device, or a part of other timepiece components to operate the same. circuit.