JPS58107026A - Circuit for charging condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a capacitor charging circuit, and is a charging circuit that reduces energy loss during charging of a high-energy capacitor used for operating an electric bicycle.

There are a number of electrical devices that utilize high-density energy generated by discharging energy stored in capacitors, such as electrical discharge machines, laser processing machines, razor scalpels, and defibrillators. When these devices are small-sized for restraint, the power source for charging the discharge converter is inevitably a storage battery or a constant capacity battery such as a dry battery, but the storage capacity of a capacitor is large. In this case, the number of times a capacitor can be charged and discharged is extremely limited. There is an extremely strong desire to minimize the energy loss when charging a capacitor and to increase the number of times a capacitor can be charged than a battery of a given capacity. Defibrillator No. 4I is a device that resuscitates a patient who has fallen into asphyxia due to the failure of the 6 membranes by applying a high-voltage electric shock to the heart using a high-voltage, high-capacity capacitor. There are no tricks to recharging or replacing batteries, as it may be too late. On the other hand, it is dangerous for devices such as differential generators and razor scalpels to be overcharged to a voltage above the 0 constant value, so if they are charged to a voltage above a certain level, it is necessary to discharge the energy equivalent to the amount of overcharge. The energy charged in the capacitor is gradually lost as electrical energy and thermal energy, so the voltage decreases due to the absorption of zero electricity by the enzyme electrolyte that makes up the capacitor, and the discharge energy decreases significantly in a short period of time. From the end of the first 11L to the release of that energy... 4! ! If it takes a long time, you need to charge the battery. In order to avoid the hassle of repeating these charging and discharging cycles, it is possible to use an automatic charging and discharging circuit that automatically performs charging and discharging, but if an automatic charging and discharging circuit is used, overcharging The discharge is 4!
Overcharging must be avoided as much as possible since it results in the greatest energy loss.

The object of the present invention is to provide a capacitor charging circuit that reduces energy loss as much as possible when charging a capacitor from a battery, and avoids overcharging to avoid losses due to discharge.

The first feature of the charging circuit of the present invention is that a pulse width modulator (pwM) is used as a pulse oscillator that converts a DC power source of a battery into an intermittent pulsed current. Second
The feature of the PWM input terminal ζ is that the voltage obtained by comparing the energy value of the capacitor set in advance and the energy value charged in the capacitor by a comparator is input, and as charging progresses, the pulse width automatically changes. However, the pulse width is set to be 11 even if the installed energy value and the charging energy value become equal. The third feature is that MO8JFE is ideal as an amplifier for pulse waves formed by PWM.
The use of T reduces energy loss in the amplification and step-up transformer circuits.

The present invention will be briefly explained below with reference to the drawings. Figure 11 is an example of a charging circuit for a capacitor used in a defibrillator. (11 is a digital switch for automatically setting charging energy, and its digital value is
It is converted by an analog (D/A) converter (2) and applied as a voltage signal to one input of the comparator (3), which serves as the output of the capacitor +91.
1 enters the other input terminal of the comparator (3), and the voltage difference between the two input terminals enters the input terminal of the pulse width modifier PWM (4). P W M (The reference voltage signal from the reference offset voltage generator (5) is also input to 41, and a pulse signal whose pulse width changes according to the difference between the reference voltage signal and the voltage signal from the comparator (3) is input. It is oscillated. Compare the pulse signal city from the divider! When the voltage signal is not sent to 131, it becomes large, and the voltage of minute@ban rises and %D
/ The pulse width gradually decreases as it approaches the set voltage sent from the A converter, but when the set voltage is reached, the comparator (3
Even if the two input power signals become equal, the pulse width does not become zero, and the pulse width generated by PWM at a constant θ voltage is increased so as to maintain a constant pulse width.

As the PWM (4), for example, a model 8G3524 manufactured by Texas Instruments Co., Ltd. is used. Furthermore, this 5G352
In the 4 type, the reference voltage generator (5) is built into the PWM (41).The signal that exits the PWM (41) enters the pulse amplification circuit C61, where it becomes a large current pulse and is passed through the pulse transformer (41). 7) After boosting the voltage, the high voltage voltage doubler rectifier 181
The voltage is further boosted from G, and the main capacitor is rectified.
(Power is stored in 91. 0υ is a changeover switch for automatic and manual charging, aa is a manual push button switch, and a3 is a manual signal.

Figure 2 is an example of the circuit of the pulse amplification circuit (6) and pulse transformer (7) connected to PW M (41). Pulses are obtained alternately, each pulse having α4; and a4
They are output alternately from the f terminal. The output circuits I and 04f are respectively connected to the input circuits of the first stage transistors (15+ and 06) of a pulse amplification circuit such as a Darlington circuit, and are further connected to the input circuits of the second stage transistors a5f and O white, respectively. The generated alternating pulse 1 becomes a current and flows through the negative side circuit a71 of the pulse transformer (7). (181 is the power supply terminal of the pulse amplification circuit, where a large current is supplied from the battery. For example, if eight 1.2-inch storage batteries are used as a power source and the minimum operating voltage is 8.5-inch,
Amplified 160 times by transformer (7) to 1360V
is obtained, and this is further increased by four times the voltage (
5440V) and charges the capacitor.

To explain the charging of the capacitor by the circuit of the present invention, the pulse current generated by the PWM is initially charged to the capacitor 1 [at the start, when the voltage of the divider Q (11 is zero), the width of the two series of pulses is Each period is 50-, but the photoelectric charge of the capacitor advances by 11!lJl (IQ
As the voltage increases, the difference from the set voltage softened by the ratio softener (3) decreases, and as the output of the ratio #R decreases, the pulse width decreases and the charging speed decreases. However, the comparator (3
Even if the difference between the two input side voltages compared at 1 becomes zero,
The pulse generated by PWM is increased to a finite value (for example, a pulse period of 10 seconds), and charging continues. On the other hand, the energy that is not charged into the capacitor decreases due to energy absorption, discharge loss, heat loss, etc. as described above, but the charging speed of the capacitor decreases and the energy is either supplied from the charging circuit or released by the capacitor. If it becomes less than the amount of energy, the voltage of the divider (101) starts to decrease and the output voltage of the ratio softener increases, so the PWM moves in the direction of increasing the pulse width, but the pulse width increases slightly due to the delay in the circuit. As soon as the voltage rises, the divider voltage is set to 1.
Since the voltage exceeds ilL, the PWM is slightly exceeded and the capacitor voltage is kept constant. Therefore, the capacitor setting is
If the height of the pulse width at Vo is determined so that the power violet charged with this pulse width and the energy loss of the capacitor at 1 setting 1@ are equal to The voltage maintains a constant value around the set value.

In the present invention, at the beginning of charging, the maximum current flows into the capacitor from the battery, but at the end, the current decreases greatly, and after charging reaches a certain energy value, the photoelectric current has only the energy corresponding to the discharging energy. Since the frames are automatically arranged for supply, there is no risk of overcharging, and therefore circuits with large energy losses such as automatic discharge circuits are not required. Furthermore, it is expected to save significant energy consumption compared to the conventional automatic charging/discharging method, which stops charging when the capacitor reaches a certain level of energy and starts charging when the capacitor reaches a certain level of energy.

#! Figure 3 is a graph showing the relationship between capacitor charging time and voltage when an automatic discharging circuit is added to the circuit in Figure 1. In a, the pulse width is constant, and in b, the pulse width is modulated by PWM. This is the case.

Figure 1g4 shows an enlarged view of the portion of Figure 6 where charging and discharging are repeated.When the pulse width is constant, when the capacitor voltage reaches the charging stop setting of 1tmVo, the charging path is closed, but the advancing current Therefore, it is overcharged to V. When the pulse width is constant, the charging speed is high even at the final stage, so the overcharge value often exceeds the set value Vmax for automatic discharge start, and is reduced to 1 × 2 due to automatic discharge. The voltage gradually decreases due to absorption, leakage current, etc. When the voltage reaches the lower limit of automatic charging Vmln, the charging device is activated and the above-described overcharging-discharging process is repeated.

On the other hand, when the pulse width decreases from PWMJ, the current also decreases, and as shown in b, the charging speed at the end of i is somewhat reduced.
At a voltage near Vo, the voltage only slightly increases or decreases above and below VO, and overcharging does not occur.

Since a smart charging circuit is not stopped midway, there is no wasted current loss due to 0N-OF'F of the circuit.In the case of 0-1, the charging current has a large alternating current portion due to repeated charging and discharging, and this Energy is lost as it flows through the capacitor, but the alternating current (tlLs) of b is extremely small, so the alternating current loss is also extremely small.

In the above explanation, the pulse width was automatically adjusted and charging and discharging were in balance when the voltage that conflicted with the capacitor energy key setting and the energy of the divider became approximately equal. It is optional to design the capacitor so that charging and discharging are balanced at a point where the voltage of the capacitor is slightly higher or lower than the general value.

The capacitor charging circuit using PWM of the present invention is s e
For example, if a film with high absorption of cast electricity, such as polyvinylidene fluoride film, is used as the electrocast body, the voltage at saturation charge is high enough to exceed IKV. In the circuit diagram, the amplifiers of the pulse amplification circuit are a5+ asr and 06+Qσ
It was explained that it has an amplification circuit having transistors such as. In fact, even in the condenser light 11L circuit of a commercially available defibrillator for restraint, which has a pulse amplification circuit from a pulse generator without a pulse width change wI4 mechanism, a transistor is used as the amplification device. When the pulse wave generated by a pulse generator is amplified by an amplifying circuit and then stepped up using a transformer, there is a drawback that heat generation in the transistor and transformer is extremely large.

In the charging circuit of the present invention, as the amplifier of the pulse amplifying circuit, preferably tL< is MOSFET or V-MOSF.
By using ET, we succeeded in further reducing the heat generation of the amplifier and step-up transformer circuits. In other words, the pulse wave obtained from a PWM oscillator contains high frequencies, but when the pulse wave P shown in Figure 5 is input to a transistor, due to the characteristics of the transistor...the radio wave is generated by the rising part of the pulse like P2. 8. But overshoot, the falling part S2 is #1! is a wave with vertical angles. Two series of pulse waves with such waveforms flow alternately in opposite directions in the primary circuit of the transformer, creating an alternating pulse current. When this primary 'NL flow is fermented in the transformer, the secondary 11ILR is P. It becomes a wave with rounded edges at the falling part like , and the energy in the part 81 and S2 remains in the primary circuit and is mainly used as heat generation in the transistor and transformer.

The heat generated not only results in significant energy loss, but also requires extra equipment such as cooling fins to cool the circuit, which increases the weight of the device.

The overshoot part of a normal pulse wave is a collection of harmonics and is easily oscillated at high frequencies, so there is a risk that it will cause high-frequency noise that may interfere with the defibrillator's own electrical circuit or electrical equipment placed around it. , it is also necessary to add noise prevention e411I.

The drain-source voltage vns and drain current RID of MO8PET are such that the drain current is constant over a wide range of drain-source voltages, and since it is a majority carrier element, it has broadband characteristics. Therefore, even if a pulse wave like P in Figure 5 is input, there will be no overshoot due to high frequency and it will not rise, so even if the alternating current synthesized from this pulse wave is stepped up from the transformer, the primary circuit In addition to having low heat loss, M (J81
1'ET has a positive temperature coefficient of ON resistance between drain and source, so if the temperature rises, the current decreases, so there is no risk of thermal runaway, and the excellent high frequency oscillation is greatly reduced, so cooling is required. Fins, radio interference prevention devices, etc. can also be omitted or simplified.

When using a MOSFET (MO8F), the Darlington circuit shown in Figure 2 can be replaced with a 6-digit MOSFET as it is, but a V-MOSFET with a high amplifier using a two-stage amplification like the Darlington circuit is advantageous. Generally, a single-stage or multi-stage amplifier is provided in front of the MOSFET. For example, an operational amplifier is used as the amplifier, but it is wise to select an amplifier that can provide an output wave that does not cause overshoot when a pulse signal is input. However, even if the output wave of the amplifier overshoots, some overshoot can be corrected by the MOSFET, and even if this correction causes the energy of the overshoot part to be consumed in the circuit between the amplifier and the MOSFET. , the energy of the pulse/linear current in the circuit in front of the MOSFET is extremely small, so the power dissipation in this case is extremely small.
). Therefore, it can be said that there is no need to be very careful in selecting the amplifier before At OS F B 'i'. A circuit using MOSFET is as shown in Figure 2.
#1 of a circuit using a transformer (7) with power input terminal 08 in the center modified to match the MOSFET
Alternatively, it is also possible to do as shown in FIG. 6, for example. In Figure 6, a9 is an amplifier, C)01 and (2tr are bias devices s (211 is P-type V-MO8F'ET%CI
'2+ is an n-type V-MOSFET. That is, PWM (4
) The pulse waves of the two systems sent from the amplifier 09 are amplified by the amplifier 09, and then converted into positive and negative pulse waves by the bias device of the other system, and the positive pulse waves are P-type V-MO8iI'ET (211, t minus pulse wave is connected to n-type V-MOSFET (
23 and become an alternating pulse current in the circuit on the negative side of the transformer (7), and then the current is amplified and charged to the main capacitor in the same way as in the case of FIG.

There are two systems of PWM pulse waves during the above glare, or PW
It is also possible to generate a pulse wave of one thread from M and convert it into positive and negative pulse waves through a bias device.The capacitor charging circuit of the present invention reduces energy loss during charging and heat generation associated with this. Since care has been taken to minimize the number of radio wave signals, it is particularly useful as a charging circuit for capacitors installed in small electrical devices such as defibrillators for restraints.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a defibrillator capacitor charging circuit showing an embodiment of the present invention, Fig. 2 is a circuit diagram of the pulse amplifier and pulse transformer shown in Fig. 1, and Fig. 3 is a circuit diagram of a defibrillator capacitor charging circuit shown in Fig. 1. A graph showing the relationship between capacitor charging time and voltage when 11 automatic discharge circuits are further provided in the circuit. Figure 4 is a graph showing an enlarged portion of Figure 6. Figure 5 is a waveform diagram of each part of Figure 2. , FIG. 6 is a circuit diagram of a modification of FIG. 2. In addition, in the codes used in the drawings, (11......Digital switch (2)......Bent/A transformer (3)
)・・・・・・・・・・・・Ratio W*(4)・・・
......Pulse width modulator +61-...
......Pulse amplification circuit (7)...
・・・・・・・・・Pulse transformer (8)・・・・・・
・・・・・・・・・Voltage doubler rectifier (91・・・・・・
・・・・・・・・・Main capacitor aα・・・・・・・・・
...It is a divider. Agent Shed Figure 3 Figure 4 Figure 5 Figure 6 Figure 6 20 m-] \ 1! 1

Claims (1)

[Scope of Claims] 1. In a capacitor charging circuit that converts current from a charging power supply battery into a pulse signal using a pulse oscillator, amplifies the pulse signal in an amplification circuit, and then boosts and rectifies it to charge the main capacitor. A pulse width modulator is used as the pulse oscillator, and a signal from an energy level regulator for charging the main capacitor and a signal from a divider connected to the output terminal of the main capacitor are input. A comparator for obtaining a differential output is provided, the output of this comparator is coupled to the input trend of the pulse width modulator, and variations in the output of the comparator cause changes in the output pulse of the pulse width modulator. A photoelectric circuit for a capacitor, characterized in that it is configured to Claim 8 #1, characterized in that the pulse is raised to a high level so as to take up as much air as possible.
Charging circuit for the capacitor described in item 1. 3. The capacitor charging circuit according to claim 1 or 2]J, characterized in that a MOSFET is used as an amplifier of the pulse amplification circuit.