JP2001274658A - Intermittent oscillation circuit and oscillation circuit - Google Patents

Abstract

(57) [Summary] An object of the present invention is to provide an intermittent oscillation circuit capable of generating an output according to a purpose and reducing power consumption. SOLUTION: In order to solve the above problem, a current source I1 is provided.
A capacitor C1 charged by a current from the switch, a switching means Q2 for discharging the charge of the capacitor to an output terminal when the capacitor C1 is turned on, and turning on the switching means when the charged voltage of the capacitor becomes the first voltage.
Control means Q1 for turning off the switching means when the charging voltage of the capacitor becomes a second voltage smaller than the first voltage. As described above, by switching on / off of the current supply from the capacitor by the switching means and the control means, unnecessary power consumption can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intermittent oscillation circuit and an oscillation circuit, and more particularly to an intermittent oscillation circuit and an oscillation circuit for outputting a waveform for an oscillator to perform intermittent oscillation.

[0002]

2. Description of the Related Art FIG. 7 is a block diagram showing an example of a conventional intermittent oscillation circuit.

In FIG. 7, an intermittent oscillation circuit 104 includes a power supply terminal 102, a constant current source 103, a capacitor C2, an operational amplifier A1, NPN transistors Q3 to Q6, and a resistor R5.
To R13.

A power terminal 102 is connected to a constant current source 103 to supply power. The voltage V from this power supply terminal 102
cc is used as a drive power supply for the intermittent oscillation circuit 104,
A voltage is supplied to the constant current source 103. The constant current source 103 is connected to the capacitor C2 and supplies power to the capacitor C2. The capacitor C2 is a current I2 from the constant current source 103.
When the transistor Q3 is turned on, the current I3 is discharged.

[0005] The charging voltage from the capacitor C2 is supplied to the non-inverting input terminal of the operational amplifier A1. A reference voltage (Vref) is supplied to the inverting input terminal of the operational amplifier A1. The reference voltage is generated by resistors R6, R7, R8. The reference voltage is controlled by the transistor Q4 and the resistor R9. The operational amplifier A1 outputs a high level signal when the charging voltage of the capacitor C2 is higher than the reference voltage, and outputs a low level signal when the charging voltage is lower than the reference voltage.

The output of the operational amplifier A1 is supplied to the base of a transistor Q3 via a resistor R5. Further, the voltage is supplied to the base of the transistor Q4 via the resistor R9.
Further, the voltage is supplied to the base of the transistor Q5 via the resistor R10.

When the output of the operational amplifier A1 becomes high level, the transistor Q3 is turned on to discharge the capacitor C2. When the output of the operational amplifier A1 goes high, the transistor Q4 turns on, and the reference voltage drops.

Further, when the output of the operational amplifier A1 goes high, the transistor Q5 turns on, and a current flows between the collector and the emitter via the resistor R11. On the other hand, when the transistor Q5 is turned off, the transistor Q6 is turned on, and a current flows between the collector and the emitter via the resistor R13. Further, the current from the resistor R13 is emitted as an output D.

As described above, since the intermittent oscillation circuit 104 oscillates a signal, the power of the capacitor C2 is discharged from the ground portion in the intermittent oscillation circuit. In particular, transistor Q
When 3 is turned on and a current flows, much power is released.

FIG. 8 is an operation waveform diagram of an example of a conventional intermittent oscillation circuit.

In FIG. 8, an input C shows a state of a charging voltage of the capacitor C2, an output D shows an output waveform, and a state of a reference voltage Vref.

The input waveform of the input C indicates a state where the capacitor C2 is charged and discharged from the reference voltage V5 to the reference voltage V6. In the input waveform of the input C, when the charging voltage of the capacitor C2 becomes the voltage V5 at time t3, a current flows through the intermittent oscillation circuit 104, and the charging voltage of the capacitor C2 decreases to the voltage V6 at time t4.

An output waveform of the output D is output according to the reference voltage Vref generated by the intermittent oscillation circuit 104 at the input C. The output waveform of the output D has the reference voltage V at time t3.
When it reaches 5, a waveform of the voltage V7 is output, a waveform is output at the voltage V7 until time t4, and when it reaches the reference voltage V6 at the time t4, a waveform of the ground voltage (GND) is output.

The waveform of the output D has a constant voltage at the time of the high level and the low level, and always consumes constant power while the capacitor is being charged and discharged. Therefore, a constant waveform is output by the reference voltage generated in the intermittent oscillation circuit 104 regardless of the charging and discharging of the capacitor C2 shown in the input waveform.

The current I2 and the current I3 are I2 << I
3 to determine the charging period T1 of the input C.
And the ratio T1: T2 of the discharge period T2 to about 100: 1.

[0016]

As described above, even while the capacitor is being charged and discharged, a waveform is always output with a constant power, and the power stored in the capacitor is discharged more than necessary. Further, regardless of the input waveform, the characteristics of the output waveform are determined by the intermittent oscillation circuit and the oscillation circuit, and cannot be changed according to the purpose. Therefore, there is a problem that power consumption is increased, which hinders reduction in power consumption.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an intermittent oscillation circuit and an oscillation circuit which can solve the above-mentioned conventional problems, generate an output according to the purpose, and reduce power consumption. .

[0018]

According to the first aspect of the present invention, a capacitor (C1; C3) charged by a current from a current source (52; 11) and a capacitor (C1; C3) which is charged when turned on. A switching means (Q2; Q28) for discharging a charge to an output terminal;
1; C3) turns on the switching means (Q2; Q28) when the charging voltage becomes the first voltage, and the second charging voltage of the capacitor (C1; C3) is smaller than the first voltage. Control means (Dz1, Dz1) for turning off said switching means (Q2; Q28) when a voltage is reached.
2, R1 to R4, Q1; Dz5 to Dz7, R25 to R2
7, Q21 to Q23, 12).

According to the first aspect of the present invention, the switching means (Q2; Q28) and the control means (Dz1, Dz
2, R1 to R4, Q1; Dz5 to Dz7, R25 to R2
7, Q21 to Q23, 12) and a capacitor (C1; C)
By switching on / off the supply of the current from 3), unnecessary power consumption can be prevented.

According to a second aspect of the present invention, there is provided an intermittent oscillating means (100; 101) for outputting an oscillating signal intermittently, and a switching device driven in accordance with the oscillating signal level of the intermittent oscillating means (100; 101). The intermittent oscillation means (100; 101).
The output oscillation signal level of the switching element (44)
Is set near the minimum switching level.

According to the invention described in claim 2, the switching element (4) set near the minimum switching level
By switching the output of the oscillation signal using 4), the power consumption can be reduced.

Note that the reference numerals in parentheses above are given to facilitate understanding of the present invention, and are merely examples, and the present invention is not limited to these.

[0023]

FIG. 1 is a diagram showing a power supply circuit using an intermittent oscillation circuit according to one embodiment of the present invention.

In FIG. 1, a power supply circuit 40 includes a power supply 43
And the load 42, and the AC of the power supply 43 is rectified into the DC of the load 42. The power supply circuit 40 includes the intermittent oscillation circuit 10
0, oscillator 20, drive circuit 30, transformers N1, N
2. Diode bridge 41, N-channel MOSFET
(Field effect transformer)
44, a resistor R.

The transformer N1 transforms the AC from the power supply 43, and the diode bridge 41 full-wave rectifies the transformed AC to DC. The rectified DC voltage is applied to the transformer N
2 and supplied to the intermittent oscillation circuit 100. In the transformer N2, the DC voltage is transformed and sent to the load. Also,
The rectification of the transformer N2 is performed by switching the N-channel MOSFET 44.

The N-channel MOSFET 44 is switched by supplying a gate voltage via the intermittent oscillation circuit 100, the oscillator 20, and the drive circuit 30. In the intermittent oscillation circuit 100, power is supplied from a diode bridge 41 to a power supply terminal 50. A voltage of approximately 140 (V) from the output of the diode bridge 41 is applied to the power supply terminal 50. The intermittent oscillation circuit 100 is approximately 140 (V)
And the intermittent oscillation circuit 100 outputs an intermittent oscillation signal of about 5.5 (V). The output signal of the intermittent oscillation circuit 100 is
Supplied to The drive circuit 30 includes the intermittent oscillation circuit 10
Driven by an output oscillation signal of approximately 5.5 (V) from 0, approximately 5 (V) is applied to the gate of the N-channel MOSFET 44.
Drive with the voltage of Also, the intermittent oscillation circuit 100
Power is supplied to the oscillator 20 and the drive circuit 30.

First, the intermittent oscillation circuit 100 supplied with power from the power supply terminal 50 converts an input current into a signal in a predetermined range and outputs the signal. The oscillator 20 outputs a waveform to the drive circuit 30 according to the output signal. Drive circuit 30 supplies a signal for turning on / off N-channel MOSFET 44.

As described above, based on the signal oscillated by the intermittent oscillation circuit 100, the N-channel MOSFET 44 is switched to perform rectification from AC to DC of the transformers N1, N2 and the diode bridge 41, and from the power supply circuit 40 to the load 42. Supply DC voltage.

FIG. 2 is an operation waveform diagram of the power supply circuit shown in FIG.

In FIG. 2, the waveform of the voltage applied to the load 42, which is the output of the power supply circuit 40, and the intermittent oscillation circuit 10
The waveform of the reference voltage Vref output from 0 and the waveform of the voltage supplied from the drive circuit 30 to the gate of the N-channel MOSFET 44 are shown.

The voltage applied to the load 42 is an N-channel MOS
It rises by the switching of the FET 44. The reference voltage Vref output from the intermittent oscillation circuit 100 from the time t5 when the power is turned on remains at the high level until the time t6 when the load-side voltage exceeds a predetermined value. The oscillation circuit 20 oscillates while the reference voltage Vref is at a high level.

The waveform of the reference voltage Vref output from the intermittent oscillation circuit 100 is such that a constant voltage is output to the oscillator 20 from time t5 to time t6. A high-frequency oscillation signal is output from the oscillator 20 to the drive circuit 30 based on the waveform of the reference voltage Vref, and the voltage from the drive circuit 30 is N
It is supplied as the gate voltage of the channel MOSFET 44.

As the waveform of the voltage supplied to the gate of the N-channel MOSFET 44, the waveform output from the drive circuit 30 is output from time t5 to time t6. The switch is switched by the voltage applied to the N-channel MOSFET 44, and the voltage is applied to the load 42. At this time, the gate of the MOSFET 44 is driven at approximately 5 (V).

FIG. 3 shows a switching characteristic diagram of one embodiment of the MOSFET 44.

When the gate-source voltage VGS exceeds the threshold value, the MOSFET 44 turns on, and the drain-source resistance RDS decreases.

Conventionally, the voltage V
9 (e.g., 10 to 15 V) to turn on, but in the present embodiment, a voltage V8 (e.g., 5
V) is applied to turn it on. This is MOSFET4
This is for reducing the power consumption when the power supply 4 is turned on.

Since the drain-source resistance RDS when the voltage V8 is applied and when the voltage V9 is applied are substantially the same value,
Driving of the N-channel MOSFET 44 can be performed normally.

FIG. 4 is a configuration diagram of an intermittent oscillation circuit according to a first embodiment of the present invention.

In FIG. 4, an intermittent oscillation circuit 100 is connected to a power supply terminal 50 and an oscillator 20, and includes a constant current source 52, a capacitor C1, zener diodes Dz1, Dz2, resistors R1 to R4, an NPN transistor Q1, and a PNP transistor Q2. Be composed.

The power supply terminal 50 has a positive electrode connected to the constant current source 52 and a negative electrode grounded. This power terminal 50
Is used as a drive power supply for the intermittent oscillation circuit 100, and supplies a voltage to the constant current source 52. The constant current source 52 is composed of a resistor, is connected to the capacitor C1, and supplies a charging current to the capacitor C1. The capacitor C1 is charged by the current I1 from the constant current source 52 and discharged to the oscillator 20 by the transistor Q2.

The Zener diodes Dz1 and Dz2 are connected in series with the same polarity, and the cathode side is connected to the constant current source 52, the capacitor C1 and the emitter of the transistor Q2. The anode side of the Zener diodes Dz1 and Dz2 is connected to the resistor R1. The resistor R1 and the resistor R2 are connected in series, and the connection point is connected to the base of the transistor Q1. The emitter of the transistor Q1 is grounded, and the collector of the transistor Q1 is connected via a resistor R3 to the base of the transistor Q2. The emitter of the transistor Q2 is connected to the constant current source 52 and the capacitor C1, and the collector of the transistor Q2 is connected to the oscillator 20 and the resistor R4. The resistor R4 is connected to the base of the transistor Q1.

Next, the operation of the circuit will be described. When the capacitor C1 is charged by the current I1 and reaches a predetermined charging voltage, the Zener diodes Dz1 and Dz2 are turned on. When the Zener diodes Dz1 and Dz2 turn on,
A current flows through the resistors R1 and R2, and the base of the transistor Q1 is set to a high level. When the base of the transistor Q1 is set to a high level, the transistor Q1 turns on. When the transistor Q1 is turned on, current is drawn from the base of the transistor Q2, the base of the transistor Q2 becomes low level, and the transistor Q2 is turned on. When the transistor Q2 turns on, the charge stored in the capacitor C1 is discharged to the output B via the transistor Q2.

At this time, the output B is fed back to the base of the transistor Q1 via the resistor R4. Even if the charging voltage of the capacitor C1 decreases and the Zener diodes Dz1 and Dz2 are turned off, the feedback from the resistor R4 causes the transistor B to return. Q2
Is kept on. When the charging voltage of the capacitor C1 further decreases, the feedback voltage from the resistor R4 decreases, and the base of the transistor Q1 becomes an off voltage, the transistor Q1 turns off.

When the transistor Q1 turns off, the base of the transistor Q2 goes high, so that the transistor Q2 turns off. When the transistor Q2 is turned off, the output B becomes low level, and the capacitor C1 starts charging again with the current I1 of the current source 52. Intermittent oscillation is performed by repeating the above operation.

As described above, in the intermittent oscillation circuit according to the first embodiment of the present invention, the electric power stored in the capacitor is discharged as an output, so that the electric power can be efficiently consumed.

FIG. 5 is an operation waveform diagram of the intermittent oscillation circuit according to the first embodiment of the present invention.

In FIG. 5, the input A is the charging voltage of the capacitor C1, the output B is the output waveform, and the Zener diode Dz
1 and Dz2.

In the input waveform of the input A, when the charging voltage of the capacitor C1 becomes the voltage V1 at time t1, current flows through the Zener diodes Dz1 and Dz2.

At time t1, Zener diodes Dz1, Dz1
When z2 turns on, the transistor Q2 turns on, and the charged voltage of the capacitor C1 is discharged to the output B.

At time t1 ', when the charging voltage of the capacitor C1 decreases and the on-voltage of the Zener diodes Dz1 and Dz2 decreases, the Zener diodes Dz1 and Dz2 are turned off. At this time, the transistor Q2 is kept on by the feedback from the resistor R4.

When the charging voltage of the capacitor C1 becomes the voltage V2 at the time t2, the transistor Q2 is turned off, so that the output B becomes low level. In addition, when the transistor Q2 is turned off, the capacitor C1 is charged.

FIG. 6 is a configuration diagram of an intermittent oscillation circuit according to a second embodiment of the present invention.

In FIG. 6, the intermittent oscillation circuit 101 includes a constant current circuit 11, a capacitor C3, a PNP transistor Q20, and NPN transistors Q21 to Q23, Q28.
And resistors R25 to R27, R30 and R31 and zener diodes Dz5 to Dz7.

The constant current circuit 11 is supplied with a voltage Vcc from a power supply terminal 50, and includes resistors R20 to R24, Zener diodes Dz3 and Dz4, transistors Q10 to Q15, and transistors Q16 to Q19.

The power terminal 50 is connected to one end of the resistor R20, and the other end of the resistor R20 is connected to one end of the resistor R21. Further, a resistor R20 having a large resistance value of, for example, several MΩ to several tens of MΩ is connected to the emitters of the transistors Q16 to Q19 forming the current mirror circuit. The reason why the resistance R20 is set to be large is to reduce current consumption. The other end of the resistor R21 is connected to the cathode of the Zener diode Dz3 of the Zener diodes Dz3 and Dz4. Zener diode Dz4
The transistors Q10 to Q connected in series
13 is grounded. Transistors Q10 to Q
Reference numeral 13 is short-circuited between the base and collector, and is so-called diode-connected. The emitter of the transistor Q11 is connected to one end of the resistor R22. The other end of the resistor R22 is connected to one end of the resistor R23 and the base of the transistor Q14. The other end of the resistor R23 is connected to a transistor Q1.
4 and the base of the transistor Q15. The collector of the transistor Q15 is connected to the collector of the transistor Q16, and the emitter of the transistor Q15 is grounded via the resistor R24.

In the constant current circuit 11, the voltage Vcc is controlled by the resistors R20 and R21, the Zener diodes Dz3 and Dz.
4. Applied to the transistors Q10 to Q13,
22, R23 and a transistor Q14.
The collector current of transistor Q15 is controlled to be constant. As a result, a constant current is generated from the collectors of the transistors Q16 to Q19 constituting the current mirror circuit.

The collector of the transistor Q17 is connected to the capacitor C3, the emitters of the transistors Q20, Q26 and Q27, the cathode of the Zener diode Dz5, and the resistor R2.
8 and R30 are commonly connected to one end of each. The collector of the transistor Q20 is connected to a Zener diode Dz.
5 and the cathode of a Zener diode Dz6. This transistor Q20 is provided to provide hysteresis characteristics.

The anode of the Zener diode Dz6 is
It is connected to one end of the resistor R26. The other end of the resistor 26 is connected to one end of the resistor R27 and the base of the transistor Q21. The collector of the transistor Q18 is connected to the collector of the transistor Q21 and the base of the transistor Q22. The collector of the transistor Q19 is connected to the collector of the transistor Q22 and the transistor Q22.
23 bases.

The other end of the resistor R28 is connected to a transistor Q
24 and the base of the transistor Q25. The emitter of the transistor Q25 is connected to the resistor R2.
9 and the base of the transistor Q24. The emitter of the transistor Q24 is the transistor Q2
3 and the other end of the resistor R29, the resistors R28 and R29 and the transistors Q24 and Q25 constitute the constant current circuit 12. The other end of the resistor R29 is connected to the base of the transistor Q20 via the resistor R25.

The transistors Q26 and Q27 form a current mirror circuit. The bases of the transistors Q26 and Q27 and the collector of the transistor Q26 are connected to the transistor Q2.
5 collectors. Transistor Q27 is connected to the cathode of Zener diode Dz7 and the base of transistor Q28.

The other end of the resistor R30 is connected to the collector of the transistor Q28. Transistor Q2
The emitter 8 is grounded via a resistor R31 and is connected to the oscillator 20.

Next, the operation of the circuit will be described. The capacitor C3 is charged by the collector current (constant current) of the transistor Q17 of the constant current circuit 11.

When the capacitor C3 rises, the voltage applied to the Zener diodes Dz5 and Dz6 is reduced by the Zener diode.
If the ON voltage of the diodes Dz5 and Dz6 is exceeded, a current flows through the resistors R26 and R27, and the base of the transistor Q21 is set to a high level. The transistor Q21 turns on when the base goes high. When the transistor Q21 turns on, the base potential of the transistor Q22 decreases, so that the transistor Q22 turns off. When the transistor Q22 turns off, the base potential of the transistor Q23 increases, so that the transistor Q23 turns on. When the transistor Q23 is turned on, the transistors Q24 and Q25, the resistors R28 and R29, and the transistor Q
The constant current circuit 12 constituted by the transistors 26 and Q27 operates, and a current flows through the Zener diode Dz7.

At this time, a current is drawn from the base of the transistor Q20 by turning on the transistor Q23,
The transistor Q20 turns on. When the transistor Q20 is turned on, the Zener diode Dz5 is bypassed. By bypassing the Zener diode Dz5, a hysteresis characteristic is provided as in the first embodiment.

When the transistor Q 27 is turned on, the transistor Q 28 is turned on and current is supplied to the oscillator 20. When the transistor Q28 turns on, the capacitor C3 is discharged. Capacitor C
The discharge current of No. 3 is supplied to the oscillator 20.

The discharging causes the charging voltage of the capacitor C3 to decrease with time, and when the Zener diode Dz6 turns off, the transistor Q21 turns off. As a result, the transistor Q22 is turned on, and the transistor Q23 is turned on.
Turns off. When the transistor Q23 is turned off, the constant current circuit 12 including the transistors Q24 and Q25 and the resistors R28 and R29 stops operating, and the transistor Q2
6. The collector current of Q27 does not flow. At the same time, the transistor Q23 is turned off and the transistor Q23 is turned off.
20 turns off, and the base voltage of the transistor Q21 decreases. The capacitor C3 is constantly connected to the transistor Q1.
7 is charged by the collector current.

[0067]

According to the intermittent oscillation circuit of the present invention, unnecessary power consumption can be prevented by switching on / off the supply of current from the capacitor by the switching means and the control means.

According to the intermittent oscillation circuit of the present invention, the power consumption can be reduced by switching the output of the oscillation signal using the switching element set near the minimum switching level.

[Brief description of the drawings]

FIG. 1 is a diagram showing a power supply circuit using an intermittent oscillation circuit according to one embodiment of the present invention.

FIG. 2 is an operation waveform diagram of the power supply circuit of FIG.

FIG. 3 shows a switching characteristic diagram of an embodiment of the MOSFET 44.

FIG. 4 is a configuration diagram of an intermittent oscillation circuit according to the first embodiment of the present invention.

FIG. 5 is an operation waveform diagram of the intermittent oscillation circuit according to the first embodiment of the present invention.

FIG. 6 is a configuration diagram of an intermittent oscillation circuit according to a second embodiment of the present invention.

FIG. 7 is a configuration diagram of an example of a conventional intermittent oscillation circuit.

FIG. 8 is an operation waveform diagram of an example of a conventional intermittent oscillation circuit.

[Explanation of symbols]

 10, 100, 101, 104 Intermittent oscillation circuit 11, 12 Constant current circuit 20, 101 Oscillator 30 Drive circuit 40 Power supply circuit 41 Diode bridge 42 Load

Claims (2)

[Claims] A capacitor that is charged by a current from a current source; a switching unit that discharges a charge of the capacitor to an output terminal when the capacitor is turned on; Control means for turning on the switching means and turning off the switching means when the charged voltage of the capacitor becomes a second voltage lower than the first voltage. 2. An oscillation circuit comprising intermittent oscillation means for outputting an oscillation signal intermittently and a switching element driven in accordance with the oscillation signal level of said intermittent oscillation means, wherein an output oscillation signal level of said intermittent oscillation means is provided. Is set near the minimum switching level of the switching element.