JPS5828604B2 - High voltage large current constant voltage power supply - Google Patents

Description

[Detailed description of the invention] The present invention relates to a constant voltage generation circuit that outputs high voltage.

For example, a high constant voltage generation circuit for operating a photomultiplier etc. includes a plurality of control transistors connected in series,
and a circuit that detects an error in the output of this constant voltage circuit,
The output of the detection circuit controls the collector-emitter resistance of the control transistor and converts the voltage of the unstable power supply into a constant voltage.

The reason why multiple control transistors are used in the above circuit is that if the output of this circuit is short-circuited and a high voltage is applied to the control transistor, the high voltage is divided by each transistor, and the individual This is to prevent voltage damage to the transistor.

However, in the above-mentioned type of constant voltage generation circuit, the base current of multiple control transistors is supplied from an unstable power supply, so a correspondingly large capacity of the unstable power supply is required.
Another drawback is that the variable range of the output voltage of this constant voltage generating circuit is limited.

On the other hand, in order to solve this drawback, a photocoupler that responds to the output of the error detection circuit mentioned above and a power supply that supplies the base current of multiple control transistors are separately provided, and the photocoupler generates a constant voltage that controls the base current. A circuit has been proposed, but this type of circuit has the following drawbacks: Since the output of this constant voltage circuit is a high voltage, the above-mentioned other power supply also has a high voltage, so that this other power supply has a high voltage. The reason for this is that the photocoupler needs to have high voltage resistance with respect to earth, and the photocoupler also needs to have high voltage resistance.

That is, the latter conventional constant voltage circuit has the drawback that a circuit with high withstand voltage must be used for transmitting the output of the error detection circuit to the input of the control transistor.

Furthermore, the use of a photocoupler has the disadvantage that the range in which the input of the control transistor can be controlled with high precision in accordance with the output of the error detection circuit is narrow, and the control range of the output of the constant voltage circuit is also narrow.

The purpose of the present invention is to efficiently convert the voltage of an unstable power supply into a very stable constant voltage, and also to arbitrarily increase the withstand voltage of the circuit that transmits the output of the error detection circuit to the input of the control transistor. An object of the present invention is to provide a high constant voltage generation circuit that can supply an output current.

Next, the present invention will be explained in detail based on examples.

In the first embodiment of the present invention shown in FIG. 1, the collector of a control transistor 4 is connected to the positive terminal 2a of the unstable power source 2, and the collector of a control transistor 4' is connected to its emitter. ing.

The emitter of the control transistor 4' is connected to the output terminal 10a of this constant voltage generating circuit.

On the other hand, the negative terminal 2b of the unstable power supply 2 is connected to the other output terminal 10b of the constant voltage generation circuit via the short circuit detection circuit 20.

Since the output terminal 10b is grounded, this constant voltage generating circuit generates a positive output voltage.

The error detection circuit 12 has an input terminal as an output terminal 10a,
10b, detects the amount of error in the actual output voltage with respect to the set value of the output voltage of the constant voltage generation circuit, and generates an output according to the amount of error.

The output of the detection circuit 12 is an automatic gain control device 14 (hereinafter referred to as A).
GC).

The AGCI 4 converts the AC output of the oscillator 16 into an AC signal with an amplitude corresponding to the magnitude of the output of the detection circuit 12, and sends it to the coil L3.

The AGCI 4, oscillator 16, and coil L3 constitute a control radio wave generation circuit.

The coil L3 is placed on the printed board at a predetermined distance from the coils L2 and L2' for high frequency coupling with the coils L2 and Lz.

As shown in FIGS. 1 to 4, if the circuit configuration on the coil L2 side is 5a and the circuit configuration on the coil L2' side is 5b, then 5
Since circuits a and 5b have exactly the same configuration, the operation of the circuit will be explained only for circuit 53.

Diode D2 is a detection diode.

Capacitor C6 and resistor R0 smooth the signal detected by diode D2.

There is an amplification transistor 6 having its own emitter coupled to the base of the control transistor 4.

Note that the amplification transistor 6 constitutes a signal amplification circuit C.

A radio wave signal of a magnitude corresponding to the output of the error detection circuit 12 transmitted from the coil L3 is received by the coil L2,
Coil L2, capacitor C5, resistor R1, diode D
2, the signal is rectified and smoothed into a DC voltage having a magnitude according to the amplitude of the radio wave signal, and is applied to the base of the amplification transistor 6.

Therefore, the coil L2, the capacitor C5, the resistor R1, and the diode D2 constitute a control current conversion circuit A that converts the radio wave transmitted by the coil L2 into a control current and supplies it to the amplification transistor 6.

In order to avoid interference between the AC signal transmitted from the coil L3 and the AC signal transmitted from the coil L4, the power multiplier 18 multiplies the AC frequency from the oscillator 16, changes the amplitude, and transmits it to the coil. Flow to L4.

Therefore, the power multiplier 18, the oscillator 16, and the coil L4 form a radio wave generation circuit that generates high frequency radio waves that are unrelated to the output of the error detection circuit 12.

Coil L4 is placed on the printed board at a predetermined distance from coil L2 and coil W in order to perform high frequency coupling with coil L1 and coil L1'.

Coil L1 receives the radio waves transmitted from coil L4,
The received signal is rectified by rectifier diode D1 and smoothed by capacitor C1.

This smoothed current is supplied to the collector of the amplification transistor 6.

In this way, the energy supply circuit B consisting of the coil L4 capacitors C1 and C2 and the diode D1 converts a radio wave signal of constant magnitude into a direct current and supplies it as the collector current of the amplification transistor.

Of course, the resonant frequency of capacitor C4 and coil L2, which is a parallel resonant circuit, is the frequency transmitted from coil L3, and the resonant frequency of capacitor C2 and coil L1 is the same as coil L4.
This is to match the frequency transmitted from the source.

Therefore, the amplification transistor 6, which is the signal amplification circuit C, is supplied with collector current from the energy supply circuit B.

The base current supplied from the control current conversion circuit A and whose magnitude changes depending on the output of the error detection circuit 12 is amplified and becomes the base current of the control transistor 4.

Since the collector current of the control transistor 4 supplied from the unstable power supply 2 is large, its base current also needs to be large accordingly.

However, since the base current of the amplification transistor 6 supplied from the control current conversion circuit A is amplified by the amplification transistor 6 and supplied to the base of the control transistor 4, the control high frequency radio wave may be small. , the structure of the control radio wave generation circuits 14, 16, and 18 becomes simpler.

Also, coil L and coil L4, and coil L2 and coil L
3 are insulated from each other on the printed board, so by appropriately spacing them, the oscillator 14 receives an output of 10.
It is possible to prevent high voltage from being applied due to a short circuit between a and 10b.

Therefore, the AGC 14 multiplier power amplifier 18 and the oscillator 16 do not need to have high voltage resistance.

The operation of each of the above circuits will be specifically explained.

When the output voltage of this constant voltage circuit becomes thicker than the set value, the output voltage of the error detection circuit 12 decreases, and AGCl 4
reduces the amplitude of the control radio wave, and the control current conversion circuit A reduces the base current to the amplification transistor 6.

As a result, the base current to the control transistor 4 decreases, and its collector-emitter resistance equivalently increases.

In this way, the output voltage of this constant voltage circuit can be lowered to the set value.

Conversely, when the output voltage becomes lower than the set value, each of the above-mentioned circuits generates the opposite output, and the output of the constant voltage generating circuit increases to the set value.

In this way, this constant voltage generating circuit can always generate an output voltage equal to the set value.

Next, the operation of this circuit will be explained when a load having an extremely small resistance value is connected between the output terminals 10a and 10b, or when the output terminals are short-circuited (hereinafter referred to as short-circuit etc.).

In the case of a short circuit in the constant voltage generation circuit, the short circuit detection circuit 2
Since a large current exceeding the rated current flows through the oscillator 0, the short-circuit detection circuit 20 detects the overcurrent and stops the generation of control radio waves from the oscillator 16 via the AGCl4.

Therefore, control transistors 4 and 4' become non-conductive.

As a result, the above-mentioned large current is instantaneously reduced to a small current, and the high voltage of the unstable power supply 2 is divided by the control transistors 4 and 4' connected in series.

FIG. 2 shows a further embodiment of the embodiment shown in FIG.

As shown in FIG. 2, dashed line portions 14, 16, and 18 are circuits that respectively embody the AGC 14 oscillator 16 and the power multiplier 18 of the blocks shown in FIG.

Further, the broken line portion 20 is a short circuit detection circuit.

The effect is that when there is a short circuit between the output terminals 10a and 10b, a large current exceeding the rated current flows through the constant voltage generation circuit 20 as described above, so the short circuit detection circuit 20 detects the overcurrent. , As a result, 5CR21 becomes conductive,
Furthermore, generation of control radio waves transmitted from coil L3 is stopped.

Further, the switch 23 connected to the anode of 5CR21 is for resetting 5CR21.

Further, the broken line portions 5a and 5b have the same structure as those shown in FIG. 1 except that a capacitor C3 and a diode D3 are added.

Note that the resistors RIO+R10' connected between the collectors and emitters of the control transistors 4 and 4' have equal high resistance values, and when the circuit is short-circuited, the voltage of the unstable power supply is applied to both transistors 4 and 4'. It functions to apply the voltage evenly.

In the embodiment described above, the output of the error detection circuit 12 is converted into the amplitude of high-frequency radio waves and transmitted to the control transistor.
Next, a second embodiment in which the above output is converted into a high frequency radio wave frequency and transmitted to the control transistor 6 will be described with reference to FIGS. 3 and 4.

The broken line parts 5a and 5b in FIG. 3 are the same as the parts 5a and 5b in FIG. 1, and the broken line parts sa and sb in FIG.
They have exactly the same configuration as b.

In FIG. 3, the frequency modulation oscillator 30 is connected to the detection circuit 12.
connected to the output of

Therefore, the frequency of the oscillator 30 changes according to the output voltage of the detection circuit 12, so the output of the detection circuit 12 is converted to the frequency of the radio wave transmitted from the output coil L5, and the control current conversion circuit A is converted to the frequency of the radio wave transmitted from the output coil L5. for amplification] is applied to the base of the Ranjistaro.

That is, the control current conversion circuit A causes a current approximately proportional to the frequency of the radio wave received by the coil L2 to flow through the base of the amplification transistor 6.

Further, the oscillator with power amplifier 32 functions similarly to the power amplifier 18 and oscillator 16 of the first embodiment, and transmits radio waves to the energy supply circuit B from the coil L6.

Therefore, the signal amplifier circuit C for amplification is supplied with collector current from the energy supply circuit B.

The control current from the control current conversion circuit A whose magnitude changes depending on the output of the error detection circuit 12 is transmitted to the amplification transistor 6.
The signal is amplified by and applied to the base of the control transistor 4.

When the output voltage of this constant voltage circuit becomes larger than the set value, the output voltage of the error detection circuit 12 decreases, the frequency of the radio signal transmitted from the coil L of the frequency modulation oscillator 30 decreases, and the control current conversion circuit A is the amplification transistor 6
Decrease the base current of

As a result, the collector-emitter resistance of the control transistor 4 equivalently increases as in the first embodiment.

In this way, the output voltage of this constant voltage circuit can be lowered to the set value.

Conversely, when the output voltage becomes lower than the set value, each of the above-mentioned circuits generates the opposite output, and the output of the constant voltage generating circuit is lowered to the set value.

In this way, this constant voltage generating circuit can always control the output voltage to be equal to the set value.

In this embodiment, since the output terminal 10a is grounded, this constant voltage generating circuit generates a negative output voltage.

Next, the operation of the short circuit detection circuit will be described. The short circuit detection circuit is composed of the transistor 3 and the resistor 11 installed between its base and emitter.

In the case of a short circuit in the constant voltage generating circuit, a large current exceeding the rated current flows through this circuit, so the overcurrent is detected by the resistor 11 and the transistor 3, and the transistor 3 becomes conductive.

Due to this conduction, the frequency of the radio wave from the frequency modulation oscillator 30 is very different from the resonant frequency of the control current conversion circuits A and X, and therefore the base current from the control current conversion circuits A and A to the amplifying transistors 6 and 6' is This becomes almost zero, increasing the equivalent collector-emitter resistances of control transistors 4 and 4'.

In this way, the large current mentioned above is instantly reduced to a constant small current,
The high voltage of the unstable power supply 2 is divided by control transistors 4 and 4' connected in series with each other.

FIG. 4 shows a concrete embodiment of the frequency modulation oscillator 30 and the oscillator with power amplifier 32 of the embodiment shown in FIG.

The frequency modulation oscillator 30a includes a coil 31 and a capacitor 34
a, 34b, 34c, 34d and a variable capacitance diode 36a connected in parallel to the capacitor 34a.

A high frequency wave having a frequency determined by the resonant circuit 36b is generated, and the alternating current is amplified by the amplifier circuit 30b and emitted from the output coil L.

Since the cathodes of the variable capacitance diodes 36a and 36b are connected to the output of the error detection circuit 12, the capacitances of the variable capacitance diodes 36a and 36b change depending on the output voltage of the detection circuit 12.

Therefore, the frequency of the oscillator 30a changes according to the output voltage of the detection circuit 12.

The broken line part 32a constitutes an oscillator, and the broken line part 32b amplifies the radio wave signal oscillated from the oscillator 32a, and oscillates it from the coil L to the coil L1 and the coil L1'.

Next, a third embodiment in which the output of the error detection circuit 12 is converted into the phase of a high-frequency radio wave and transmitted to the control transistor will be described in the fifth embodiment.
This will be explained with reference to FIG.

In FIG. 5, the output of oscillator 42 is output to phase shift circuit 44.
, an AGC circuit 46 and an amplifier 48.

Amplifying circuit 48 amplifies the output of oscillator 42 and transmits a reference phase radio signal, +R, from output coil L8.

The AGC circuit 46 changes the amplitude of the output of the oscillator 42 according to the magnitude of the output of the error detection circuit 12.

The signal synthesis circuit 50 outputs the output of the oscillator 42 shifted by, for example, π/2 by the phase shift circuit 44 and the output of the oscillator 42 which is amplitude-modulated in accordance with the output of the error detection circuit 12 in the AGC circuit 46. Synthesize.

The output of this synthesis circuit 50 is amplified by an amplifier 52, and a control radio wave signal fs is generated from its output coil L7.

The control radio signal fS from the coil L7 is different from the reference phase radio signal fR from the coil L8 in the error detection circuit 1.
It has a phase difference corresponding to the output of 2.

In Fig. 5, parts 15a and 15b correspond to parts 1 to 4.
Since it has exactly the same configuration as the relationship between 5a and 5b in the figure, only 15a will be explained.

In FIG. 5, the phase difference detection circuit 54 has an output coil L8.
The detection circuit 54 has a coil 54a that receives the reference radio wave fR from the output coil L7, and a coil 54b that receives the control radio wave fS from the output coil L7. A base current is passed through the amplification transistor 6.

In this way, the output of the error detection circuit 12 is the radio signal fR2f
It is converted into a phase difference of s and transmitted to the amplification transistor 6.

On the other hand, the energy supply circuit 56 functions exactly the same as the energy supply circuit B of the first and second embodiments.

Further, as in the previous embodiment, since the base of the control transistor 4 is connected to the emitter of the amplification transistor 6, the current flowing through the control transistor 4 can be controlled according to the output of the error detection circuit 12. That's why.

To specifically explain the action of the broken line 15a, when the output voltage of this constant voltage circuit becomes larger than the set value, the output voltage of the error detection circuit 12 decreases, and the output coil L of the amplifier 52
A phase difference detection circuit 54 that detects the phase difference between the radio signal fs transmitted from the amplifier circuit 7 and the radio signal fR transmitted from the output coil L8 of the amplifier circuit 48 reduces the base current supplied to the amplification transistor 6.

As a result, the collector of the control transistor 4 is equivalently
Emitter resistance increases.

In this way, the output voltage of this constant voltage generating circuit can be lowered to the set value.

Conversely, when the output voltage becomes lower than the set value, each of the circuits described above generates an opposite output, and the output of the constant voltage generating circuit can be controlled to the set value.

In this embodiment, PNP transistors were used as the control transistor 4 and the amplification transistor 6, unlike the NPN transistors used in FIGS. 1 to 4.
It goes without saying that the effects of the present invention will not change even if a PN type transistor is used, and the effects of the invention will not change even if a PNP type transistor is used in FIGS. 1 to 4.

Next, based on FIG. 6, a detailed explanation will be given of an embodiment in which the control transistor 4 and the amplification transistor 6 are NPN type transistors to embody the structure shown in FIG.

The 7 phase shift circuit 44 consisting of a capacitor and a resistor is an AGC
It is connected to the collector of the transistor of circuit 46.

Therefore, the output of the phase shift circuit 44 and the output of the oscillator 42 whose amplitude is modulated according to the output of the error detection circuit 12 are combined here, so that the output of the coil 45 and the output of the oscillator 42 are combined. produces a phase difference depending on the output of circuit 12.

The output of coil 45 is amplified, emanates from coil L7, and is received by coils 54b, 54b'.

Next, the phase difference detection circuit 54 will be explained.

This includes two pairs of diodes 54c, 54d.

The coil 54a receives the reference radio signal fR from the output coil L8.
Depending on the polarity of the electromotive force generated thereon, one pair of diodes 54c or 54d becomes conductive and the other pair becomes non-conductive.

Therefore, when the pair of diodes 54c are conductive, the coil 5
4b between AB is connected to the base of the control transistor 4, and conversely, when the other diode pair 54d is conductive,
The portion between BC and BC of the coil 54b is connected.

Therefore, when the phases of both signals fR and f8 are in phase, the output of the coil 54b has a value similar to the output waveform when the signal fS is full-wave rectified, but if a phase difference occurs between the two signals, , the amplitude of the control signal fs corresponding to the difference is removed and then smoothed by the resistor R1 and the capacitor 58, so the magnitude of the current flowing to the amplification transistor 6 is:
It is determined by the phase difference between the reference radio signal fR and the control radio signal fs.

In the third embodiment, the reference radio wave signal and the control radio wave signal having the same frequency are used, but in order to prevent interference between the two signals, for example, the coil L7 and the coil 54b are placed almost parallel to each other and in the same manner. The coil L8 and the coil 54a may also be arranged substantially parallel to each other, and the coil L7.54b and the coil L8.54a may be arranged at right angles to each other.

The energy supply circuit 56 also includes a coil 56a and a diode D1. D2, and capacitors C1, C2, and C3, and supplies the reference radio wave signal fR transmitted from the output coil L3 to the amplification transistor 6 as its collector current.

As described above, according to the present invention, since the circuit for transmitting the error signal to the control transistor is composed of a high frequency transmitter and a receiver, insulation between the transmitter and receiver can be maintained by appropriately setting the distance between the transmitter and the receiver. Therefore, the signal transmission circuit described above can be arbitrarily and easily made to have a high breakdown voltage.

Furthermore, since the control current from the receiver is amplified and supplied to the input of the control element, the control radio waves from the transmitter can be small, and as a result, the control radio wave generation circuit 14.16 .18:30, 32:42, 44, 46
The circuit configurations of 48, 50 and 52 become extremely easy, and the performance of converting the output of the error detection circuit into high frequency radio waves is improved.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing a part of a first embodiment of the present invention, FIG. 2 is a specific circuit diagram of the first embodiment, and FIG.
The figure is a circuit diagram showing a part of the second embodiment of the present invention in block form, FIG. 4 is a specific circuit diagram of the second embodiment, and FIG. 5 is a part of the third embodiment of the present invention. FIG. 6 is a circuit diagram shown in blocks, and is a specific block diagram of the third embodiment. Explanation of symbols of main parts, 12...Error detection circuit, 4...Control element, 14...AGC circuit, L3...Coil, 18... ...multiplier power amplifier, 16...oscillator, L4...
Coil, B...Energy supply circuit, A...
... Control current conversion circuit, 30 ... Frequency modulation oscillator, L, ... Coil, 32 ... Oscillator, L6 ... Coil, 42 ... ...Oscillator, 44...Phase shift circuit, 46...
A()C circuit, L7... Coil, 50...
・-Coupling synthesis circuit, L8... Coil, 20...
...Short circuit detection circuit.

Claims (1)

[Scope of Claims] 1. A high constant voltage generation circuit that converts a high voltage of an unstable power source 2 into a constant voltage by a control element 4 that operates in accordance with the output of an error detection circuit 12 that detects an error in the output voltage, comprising: a signal amplification circuit C connected to one input terminal of the control element 4; a control radio wave generation circuit L3, 14, 16 that generates a control high frequency radio wave according to the output of the error detection circuit 12; and the error detection circuit Radio wave generation circuit L4, 16.18 that generates high frequency radio waves of a constant size that is unrelated to the output of the circuit 12.
and a control current conversion circuit that receives the control high frequency radio wave, converts it into a control electric signal of a magnitude corresponding to the output of the error detection circuit 12, and is connected to the other input terminal of the signal amplification circuit C. A, the signal amplification device that receives the high frequency wave of a certain magnitude, converts it into an electric signal, amplifies the control electric signal with the converted electric signal, and applies it to the input of the control element 4; A high constant voltage generation circuit, comprising: an energy supply circuit B connected to the other input end of the circuit C, and transmitting the output of the error detection circuit 12 to the control element 4 by high-frequency radio waves. 2. The high constant voltage generation circuit according to claim 1, wherein the control radio wave generation circuit generates a radio wave having an amplitude that changes depending on the output of the error detection circuit. Voltage generation circuit. 3. The high constant voltage generation circuit according to claim 1, wherein the control radio wave generation circuit generates radio waves having a frequency that changes depending on the output of the error detection circuit. generation circuit. 4. The high constant voltage generation circuit according to claim 1, wherein the control radio wave generation circuit generates radio waves having a phase that changes depending on the output of the error detection circuit. circuit. 5. In the high constant voltage generation circuit according to claim 1.2.3 or 4, the control element is a transistor, and its collector and emitter are connected to the output terminal of the unstable power source and the high constant voltage generation circuit. A high constant voltage generation circuit characterized in that it is connected between an output terminal and an output terminal. 6. The high constant voltage generation circuit according to claim 5 has a short circuit detection circuit for detecting short circuits, etc. of the high constant voltage generation circuit, and the detection output of the short circuit detection circuit is equivalent to that of the control transistor. A high constant voltage generation circuit, characterized in that a radio wave that increases collector-emitter resistance is generated from the high frequency radio wave generation circuit.