JPH07193429A - High voltage oscillator circuit - Google Patents

Abstract

PURPOSE:To generate high voltage from power supply voltage without a special booster circuit by connecting one end of a ceramic resonator with the input of a CMOS inverter via a capacitor and taking out an output from the connection point. CONSTITUTION:A CMOS inverter IC 2 operates as an analog amplifier and the output of an amplifier 2 is grounded via a resistor R1-4, a ceramic resonator 3, and capacitors C3-7 and C1-5. These elements including the oscillator 3 compose a serial resonance circuit and current i flows. When the capacitance of the capacitor C3 is made smaller as compared with the capacitors C1 and C2 or impedance is made higher, the voltage VC3 across the capacitor C3 becomes the value i/jomega C3 that is the impedance 1/jomega C3 multiplied by the current i and this voltage becomes higher than the voltage across the capacitor C1. Namely, in a non-adjusted CMOS oscillator circuit, voltage which is higher than power supply voltage can be generated without a special booster circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an unadjusted oscillator circuit using a mechanical-electrical oscillator such as a ceramic resonator (ceramic oscillator) or a crystal oscillator, and more particularly to an oscillator circuit using a battery. The present invention relates to an oscillating circuit that generates a voltage equal to or higher than the power supply voltage.

[0002]

2. Description of the Related Art Conventionally, in order to generate an output voltage from a power supply voltage of a battery, a booster circuit is used separately from an oscillation circuit to generate a high output voltage. FIG. 4 shows a conventional oscillator circuit. In a conventional circuit, a negative feedback resistor R2 is connected to the CMOS inverter 2, and a mechanical-electrical vibration element 3 such as a ceramic resonator (ceramic oscillator) or a crystal oscillator is connected in parallel to this, and both ends are grounded by a capacitor. CMO
The S inverter 2 is operated as an analog amplifier. Therefore, if the negative feedback resistor R2 is connected to the CMOS inverter 2, the input potential will be near the threshold, and the output voltage will oscillate between 0 V and the power supply voltage centered at half the power supply voltage. In order to generate a higher voltage, it is necessary to boost the output with another booster circuit.

[0003]

In the above-mentioned circuit for generating an output voltage higher than the power supply voltage, since the booster is used separately from the oscillator circuit, the power supply conversion efficiency of the booster circuit becomes a problem, and especially the battery is used. However, such a device has a drawback that the battery life is shortened. Further, since a separate circuit is added, it may occupy a space, and it may be difficult to reduce the cost.

[0004]

The present invention has been made to solve the above-mentioned conventional problems, and includes a CMOS inverter IC, a mechanical-electrical vibration element such as a ceramic resonator and a crystal oscillator, and a resistor. In an unadjusted CMOS oscillation circuit including a capacitor, one end of the mechanical-electrical vibration element is connected to the CMOS inverter IC via the capacitor, and a power supply is provided from a connection point between the mechanical-electrical vibration element at the other end of the capacitor. The present invention proposes a high-voltage oscillator circuit that generates a voltage higher than the voltage.

[0005]

In the present invention, an output voltage higher than the power supply voltage is generated from the oscillation circuit itself, and a current is also applied to the resonance current series division small capacity capacitor of the mechanical-electrical vibration element.
The effect that the terminal voltage becomes higher than the power supply voltage is used.

[0006]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a circuit diagram of the present invention. In the present invention, CMOS
Inverter IC2, ceramic resonator 3 (hereinafter referred to as ceramic oscillator), resistor R1 (4), capacitor C
In the unadjusted CMOS oscillation circuit 1 including 1 (5) and C2 (6), one end of the ceramic oscillator 3 is connected to the capacitor C.
3 (7) is connected to the input of the CMOS inverter IC2, and the output is taken out from this connection point.

Next, description will be made using the equivalent circuit of FIG.
As described above, the CMOS inverter IC2 operates as an analog amplifier, and the output of the amplifier 2 is the resistor R1.
(4), ceramic oscillator 3, C3 (7), C1 (5)
Grounded through. These elements including the ceramic oscillator 3 form a series resonance circuit, and a current i flows through the series resonance circuit as shown in the figure. Here, the capacitance of the capacitor C3 (7) is changed to the capacitors C1 (5) and C2.
If it is set smaller than (6), that is, the impedance is set high, the voltage VC3 across the capacitor C3 (7) is set.
Is the impedance i / jωC3 multiplied by the current i, i /
jωC3, which is higher than the voltage across the capacitor C1 (5). It has been confirmed that the capacitance of the capacitor C3 (7) is set to be sufficiently smaller than that of C1 (5) and C2 (6), and that it is effective up to about several tenths. It has been confirmed that when the capacitance is set to a smaller value, it is saturated at a certain voltage due to other impedances, element characteristics, etc., and there is no effect. Further, as for the load impedance, the impedance 1 / jωC3 of the capacitor C3 (7) is not so low,
It is desirable to set it to 100 KΩ or more.

Another embodiment will be described with reference to FIG. In FIG. 3, a capacitor C4 (8) and a switch SW9 connected in series are connected in parallel to both ends of the ceramic oscillator 3. By closing the switch SW9, the capacitance of the capacitor C4 (8) is added, As a result, the oscillating frequency is slightly lowered, and the output voltage can be varied. It is also possible to connect a plurality of similar capacitors in parallel. In the present embodiment, the ceramic oscillator has been described as the mechanical-electric vibrator, but the present invention is not limited to this, and a crystal oscillator can also be used.

[0009]

Since the present invention has the above-described structure, it is possible to generate a voltage higher than the power source of the battery as the power source voltage without requiring a special booster circuit. According to the result of the experiment, the output voltage of 3 to 10 times was obtained. Further, the oscillation frequency can be varied by connecting the capacitor in parallel with the ceramic resonator (ceramic oscillator) or the crystal oscillator.

[Brief description of drawings]

FIG. 1 is a circuit diagram of the present invention.

2 is an equivalent circuit of FIG.

FIG. 3 Another embodiment

FIG. 4 Conventional example

[Explanation of symbols]

 1 CMOS oscillator circuit 2 CMOS inverter IC 3 Ceramic oscillator 4 Resistor 5 Capacitor 6 Capacitor 7 Capacitor 8 Capacitor 9 Switch

Claims (1)

[Claims] 1. An unadjusted CMOS oscillator circuit comprising a CMOS inverter IC, a mechanical-electrical vibration element such as a ceramic resonator and a crystal oscillator, a resistor, and a capacitor, wherein one end of the mechanical-electrical vibration element and a capacitor are connected to each other. A high-voltage oscillation circuit, which is connected to the CMOS inverter IC via a capacitor and generates a voltage higher than a power supply voltage from a connection point between the mechanical-electric vibration element at the other end of the capacitor.