JPS59156125A - Power source circuit - 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 Field of the Invention The present invention relates to a power supply circuit for supplying current to a storage battery from an alternating current voltage source or a direct current voltage source having a variable voltage value. The power supply circuit then has a clock-controlled blocking inverter in which the primary winding of the transformer of the blocking inverter is connected in series with the switching path of the first transistor and the first resistor f1. The secondary winding of the transformer is connected in series with the accumulator and the first diode nl and the first diode.
The base of the first transistor is connected to one winding end of the secondary winding of the transformer through a series connection of a feedback capacitor and a feedback resistor, and the base of the first transistor is connected through a resistor. a switching section electrode terminal of the first transistor, and a base of the second transistor connected to the first transistor;
one of the switching section electrode terminals of the second transistor is connected to ground or reference potential.

Such power supply circuits are used to power electrical or electronic equipment with a constant voltage and/or constant current, often using a blocking type inverter, which is clock-controlled on the primary or secondary side. It is configured as a controlled inverter or a push-pull inverter fL2. Typically, this power supply circuit has a rectifier circuit and a filtering and smoothing circuit connected downstream thereof, and a choke coil of a transformer is connected to the filtering and smoothing circuit. An electronic switch is provided in parallel with the primary winding or choke coil of the transformer.This electronic switch is one-1:
Continuity connection and disconnection depend on a number of controlled variables. In that case, f is stored in the transformer or choke coil.
The energy generated is correspondingly applied during the blocking period or the conduction period if the installed inverter is of the converter type or of the thyristor conduction-controlled type; The electronic switch is delivered to the electrical load via a polarized diode and operates at a frequency of approximately 20 KH2 in order to reduce its volume when using a transformer.

When electrical equipment such as an electric shaver, an electronic flash device, a wireless device, a television device, etc. is driven by a commercial power source, the electrical equipment has a storage battery. In order to charge the storage battery with a constant current, the electrical equipment is equipped with a control circuit. This control circuit has, for example, 90 to 24
Provides a constant output current for charging the storage battery even if the input voltage varies within the range of 0V. As input voltages, AC and DC voltages of 90-24-OV can be used. For alternating voltage, its frequency is 50Hz, ~6
0Hz is suitable.

A circuit device is known from Yoron ξ Patent Publication No. 80107474.1, in which power is supplied to a load in a controlled manner. This circuit arrangement can be operated without switching even if the voltage values of the alternating current or direct current voltage are different, and even if the frequency of the alternating voltage is different. The circuit arrangement also has a blocking inverter, which controls the current flowing through the primary winding of the transformer and the supplied input voltage (depending on The output charging power is controlled so as to be constant.A parallel circuit of a storage battery and a DC motor is provided as a load.Therefore, this circuit device connects to a commercial power source to operate the motor. When the motor is running, it supplies full power to the motor, and when the motor is shut off, it supplies charging current to the battery.

In this known circuit arrangement, a switching section of a first transistor is connected in series f'L ft in series with the primary winding of the transformer.
An emitter resistor and a resistor bridging the base-collector section of the switching transistor are provided. A switching section of the second transistor is provided in parallel with the series connection of the base-emitter section of the first transistor and the emitter resistor. The base of the second transistor is 1
The collector is connected to one winding end of the secondary winding of the transformer through one resistor and a feedback resistor and a capacitor.

In this known circuit arrangement, a direct voltage is applied to a series circuit consisting of a primary winding of a transformer, a first transistor and an emitter resistor. A base current therefore flows between the collector and base of this transistor via the resistor bridging the collector-base section. This base current generates a small collector current, which is
A positive voltage is induced in the primary and secondary windings by flowing through the secondary windings. This positive voltage is applied to the base of the transistor through the feedback capacitor and the capacitor connected in series with it, generating a large base current. Simultaneously with the initiation of conduction of the switching transistor, the current flowing through the primary winding of the r1 transformer increases linearly until a voltage proportional to the emitter current drops across the emitter resistor. When the voltage proportional to this emitter current reaches a predetermined value, a pace current flows through the second transistor, and this transistor is controlled to conduct. The potential at the base of the first transistor is therefore at reference (earth) potential and the first transistor is turned off. While the first transistor is blocked, the magnetic energy stored in the transformer core flows into the secondary winding. At this time, a linearly decreasing charging current is supplied to the storage battery via the conductive diode.

A disadvantage of this known circuit arrangement is that the first transformer, cluster,
Alternatively, the base-emitter voltage of the switching transistor may vary within a narrow range of 200 to 500 mV.

Even a slight change in the base-emitter threshold voltage of a switching transistor causes the point in time at which its conduction begins to change from a predetermined point in time. Since the known circuit arrangement has a small conduction initiation threshold, it is very susceptible to spikes, variations in device characteristics, and the like. Therefore, if the input voltage is 80~9
If a surge occurs in the transformer at a small value of 0V,
The switching transistor connected in series with the primary winding of the transformer is activated earlier than a predetermined time n1, so that the switching frequency increases.

As a result, the charging current of the storage battery also increases. For example, a nickel-cadmium storage battery has a charging current of 50 mA.
If the value is too high, it will be damaged, and in the above-mentioned case, the storage battery and, by extension, the circuit arrangement itself will be exposed to danger. Moreover, if the conduction of the switching transistor is controlled too early, the peak current at the emitter of this transistor will rise, making the switching transistor also dangerous.

OBJECTS OF THE INVENTION An object of the present invention is to improve a power supply circuit that supplies current to a storage battery from an AC or DC voltage source with a variable voltage value as follows.

In other words, this power supply circuit is almost unaffected by variations in element characteristics, leaks, etc. : It forms a constant secondary current from a wide range of input voltages, and is constructed with a small number of elements.

According to the invention, this object is achieved by connecting the base of the first transistor to the switching section electrode terminal of the second transistor via a second diode.

According to the power supply circuit of the present invention, the secondary current and charging frequency for charging the storage battery can be kept constant regardless of product variations, and switching can be performed when the emitter voltage reaches a certain peak value. The transistor can be shut off reliably. This is accomplished as follows. That is, the voltage difference between when the switching transistor is controlled to be conductive and when it is cut off is made several times that of a known power supply circuit, thereby increasing the temperature of the switching transistor or causing leakage in the inverter. The effect of fluctuations in the base-emitter voltage of this transistor on the secondary current is reduced to a fraction of that of known power supply circuits.

In an advantageous embodiment of the power supply circuit according to the invention, a first switch is provided in parallel with the second diode, this first switch being coupled with a second switch, the second switch being in parallel with the accumulator. The connected DC motors are connected in parallel and cut off.

Furthermore, according to the present invention, the first resistor connected in parallel with the base-emitter section of the first transistor is composed of two individual resistors, and a Zener diode is connected to the connection point of the two individual resistors. , the 77- node side terminal of the Zener diode is connected to the reference potential t or ground potential.

The above-described configuration provides the following advantages: 2714° That is, even when the polarity of the feedback capacitor changes in relation to the conduction state and cut-off state of the switching transistor,
This capacitor can be discharged. Also, since the feedback capacitor can be charged from a constant potential,
The effect of the present invention of keeping the secondary current constant over a wide voltage range can be further enhanced.

DESCRIPTION OF EMBODIMENTS Next, the present invention will be described in detail with reference to embodiments with reference to the drawings.

FIG. 1 shows a power supply circuit comprising a transformer 5 and a blocking type inverter which is clock-controlled on the primary side, a first transistor 11 and a load circuit. The first diode 7 has a The blocking injector is powered via the rectifier bridge circuit 3 and the resistor 26 from an alternating current power supply or from a direct current power supply. The voltage of this power supply is 90 to 250 square meters, and its frequency is arbitrary. An additional capacitor 25 is provided in parallel with the input terminal. Rectifier bridge circuit 3. The rectified output voltage is applied via a filtering and smoothing circuit consisting of a series choke coil 20 and two smoothing capacitors 21, 22 to the input side of the blocking inverter or control electronics.

Connected in series with the DC voltage terminals of the rectifier bridge circuit is the series connection of the primary winding 51 of the transformer 5 and the collector-emitter section of the first transistor l and its emitter resistor 13,14-. In parallel with the base-collector section of the transistor l, two resistors 61 are connected in series.
62 is provided nl at its connection point a Zener diode 12
The cathode of is connected. The anode side of the Zener diode is connected to ground potential or reference potential. The base of the first transistor 1 is connected to ground potential or reference potential via a second diode 11, the anode of which is connected to this base, and the collector-emitter section of the second transistor 2. The base of the transistor l is further connected to the winding end of the secondary winding 52 of the transformer 5 via a feedback resistor 10 and a feedback capacitor 9. The second transistor 20 is connected to the connection point of the emitter resistor 13, 14 of the first transistor 1. In addition, the emitter of the first transistor 1 is connected to the second transistor of the transformer 5 via a second capacitor 15.
It is connected to another winding end of the next winding 52 and to ground or a reference potential.

In parallel with the primary winding 51 of the transformer 5, a third diode 2
3 and a second Zener diode 2 are connected with their conducting directions reversed.

These diodes transfer the voltage that increases due to the leakage inductance when the first transistor 1 is cut off to the second transistor.
This is used to limit the voltage drop across the Zener diode 24 to the sum of the power supply voltage.

A third capacitor 18 is provided in parallel with the series circuit of the feedback capacitor 9 and the feedback resistor 10. The purpose of providing this capacitor is to prevent a so-called "reconduction control peak" from occurring in the base-emitter voltage due to the rapidly and sharply changing collector voltage of the first switching transistor 1 when it is turned off. , and in parallel with the secondary winding 52 of the transformer 5, a pre-resistor is installed, the purpose of which is to ensure that there is no delay when switching off the switching transistor, and that a quick and direct switch-off takes place. 16 and a light-emitting diode 1'17 are additionally provided in series.This light-emitting diode emits light during charging of the accumulator or when the load is activated. A parallel circuit of a storage battery 41 and a DC motor 42 is provided as a load between the anode of the diode 7 and the ground or reference potential.
The contents 19 of n1 are connected in parallel with the DC motor 42.
A frame 82 is provided in series with this motor.

The switch 82 is connected in parallel with the second diode 11.
It is mechanically interlocked with the switch 81.

Next, the operation of the circuit shown in FIG. 1 will be explained in detail.

The input AC is rectified by the rectifier bridge circuit 3? f
After filtering n by the E-series choke coil 20 - and smoothing n by the capacitor 21.22, the first transistor l, acting as a switching transistor, is controlled by a small base current through a series circuit of resistors 61.62. Sanru. The first transistor 1 is conduction controlled n
A positive feedback effect then occurs via the switch section of this transistor and the primary winding of the transformer. The first transistor is additionally controlled by this positive feedback effect and is switched into conduction. The emitter current rises linearly and the voltage proportional to the two emitter resistors 13.
Occurs on the 14th. When a predetermined peak current value is reached, the base of which is connected to the two emitter resistors 13. ．． The second transistor 2 connected to the connection point 14- is controlled 1 and becomes conductive. As a result, the base of the first transistor 1 is connected via the second diode 11 to ground or to the reference potential, so that no base current flows through the transistor 1 and is therefore blocked. At the beginning of the blocking period, the polarity of the voltage induced in the secondary winding 52 of the transformer 5 changes, so that the energy stored in the transformer 5 is transferred to the then conducting first is sent to the load 4 via the diode 7 of n. For this purpose, a load 41 consisting of a nickel-cadmium accumulator, for example.
obtains a linearly decreasing charging current. This linearly decreasing negative current blocks the first transistor l via the feedback resistor 10 and the feedback resistor 9 until all the magnetic energy stored in the transformer 5 is exhausted. The starting current then first flows again via the resistor 6:h, 62 to the base of the first transistor l. This start,
The t flow initiates the conductive connection process described above.

In the power supply circuit according to the invention, in order to switch from a large secondary current to a 4-small secondary current and to obtain a constant secondary current over a wide operating range, the feedback capacitor
Utilizes the charge stored in n. Switch δ1, 82
When it is open, a small secondary current flows, for example to charge the nickel-cadmium storage battery 41. This is very useful when a switch fails. This is because even at that time, the storage battery is charged with a small charging current.
This is because that.

While the first transistor l is conducting, the feedback capacitor 9 is positively charged at point A.

Therefore, another terminal of the feedback capacitor 9, the point E[C
A negative polarity is formed. As described above, when the emitter current of the transistor 1 reaches a predetermined value, the second transistor 2 is controlled to be conductive, and the base current of the first transistor 1 stops flowing. Transistor 1 is therefore blocked. The voltage across the secondary winding 52 of the transformer 50, induced at point AVc, switches its polarity and becomes applied in series with the voltage at the feedback capacitor 9. Since there is a second diode 11 connected with polarity in the blocking direction, the negative charge at point B is transferred through the collector-base section of the second transistor 2 and the emitter resistor lΦ even if the switch 81 is opened. It will not flow to ground or reference potential. Therefore, the resistance value of the feedback resistor 10 is extremely small compared to the resistance value of the resistor 62, so it can be ignored. the first transistor 1 until the feedback capacitor 9 charges up to the base-emitter threshold voltage of the first transistor 1 at point B.
There is no word that conduction is controlled again. During this process, the capacitor 18 connected in parallel with the series circuit of the feedback capacitor 9 and the feedback resistor 10 can be ignored.

This is because its capacitance is much smaller than that of the feedback capacitor 9.

The Zener diode 12 allows the feedback capacitor 9 to be turned off and charged from a constant potential to the base-emitter threshold voltage of the first transistor 1. This allows the secondary current to be constant over a wide operating range, resulting in a constant charging current flowing through the storage battery +1.

Cutting off the first transistor l when its emitter current is at a certain peak value results in a constant switching frequency and a constant secondary current. Therefore, a very high charging current, e.g.
Protected from charging currents greater than A. For example, 20mA
The storage battery 41 can be charged with the above relatively large charging current. At this time, for example, a charging current of 20 mA is used as a maintenance charging level.Next, the difference in switching characteristics between the power supply circuit according to the present invention and the known power supply circuit will be explained with reference to FIGS. 2 and 3.

FIG. 2 shows the time course of the voltage between the base of the first switching transistor 1 and the ground or reference potential and the emitter of the second switching transistor 2 in a known power supply circuit. The base-emitter voltage corresponding to this threshold during the start of conduction (L) of the first transistor 1 is approximately 0.55 V.The feedback capacitor 9
The voltage at which the charging time T begins and the time point T when conduction begins.

The difference from the voltage in is about 0.2■. Therefore, if the base-emitter threshold voltage of the first switching transistor changes slightly, for example due to an increase in the temperature of the first switching transistor or due to product variations, the switching time T. irl becomes faster. In other words, the second illustrator moves to the left. Due to the accompanying frequency fluctuation, the average value of the secondary charging current changes considerably. As is clear from FIG. 2, when the rising slope of the base-emitter voltage during the charging time T of the feedback capacitor 9 is small,
Even if the threshold voltage changes only slightly, the first switching transistor 1 will be turned on earlier than the predetermined point in time.

FIG. 3 shows the switching characteristics of the first switching transistor of the electronic power supply circuit according to the invention. As can be seen from this figure, during the charging time T of the feedback capacitor 9, the conduction control time T starts from the start of the charging time T. The voltage difference up to in is about 3μ. Therefore, even if the base-emitter voltage of the first switching transistor 1 changes due to a temperature rise in the first switching transistor 1 or product variations, the effect of this change on the secondary current will be 10 minutes compared to known power supply circuits. It is only one of the Furthermore, since the slope of the voltage rise is large, even if the base-emitter threshold voltage of the first switching transistor l changes, the conduction control point T is 1.
n There is only a slight displacement. Therefore, fluctuations in frequency and charging current are very small.

As can be seen from the above description, the operational stability of the power supply circuit according to the present invention, in which the secondary current and charging frequency can be kept constant, is achieved by the addition of the additional diode 11 and the Zener diode 12.
It can be obtained by only two things. This configuration ensures that the nickel-cadmium accumulator is protected from higher charging currents than in known power supply circuits. It is also ensured that the charging current of the accumulator is kept within a narrow range between maintenance charge and excessive current values that endanger the accumulator.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram of an embodiment of a power supply circuit according to the present invention, FIG. 2 is a waveform diagram of a base-emitter voltage of a switching transistor in a known power supply circuit, and FIG. 1 is a diagram showing a base-emitter voltage of a switching transistor in a known power supply circuit. FIG. 3 is a voltage waveform diagram. 1.2... Transistor, 3... Active bridge circuit, Cow... Load, 20... Choke coil, 21°2
2...Smoothing capacitor, 41...Storage battery, 42...
- DC motor, 51... primary winding, 52... secondary winding, 81. '82...Switch, T...Charging period,
To □... At the time of conduction control. Procedural amendments (six) March 1980, Mr. Commissioner of the Patent Office, 1981, Indication of the case, Patent Application No. 121 of 1982, 2, Name of the invention, Power supply circuit 3, Person making the amendment, and the case Related Patent Applicant Name Braun-Akchengesellschaft 4, Agent 5 Number of inventions increased by amendment 16 Target of amendment 7 Contents of amendment (1) The scope of the patent claims will be amended in Appendix 9. (2) Specification, page 11, lines 9 to 14 [According to the present invention......Cut off. Correct J as follows: 0 “According to the invention described in claim 3, a first switch is provided in parallel with the second diode, and the first switch is provided in parallel with the second diode.
The switch is coupled to a second switch, which activates and disconnects a DC motor connected in parallel with the storage battery. ”(3)
Page 11 of the specification, lines 18-19, "A Zener diode is connected to the connection point of the individual resistors," is corrected to "The cathode of the Zener diode is connected to the connection point of the individual resistors." 2. Claim 1: comprising a clock-controlled block-type input transformer, the primary winding of the blocking-type input transformer having a switching section of a first transistor and a first resistor; The secondary winding of the transformer is connected in series with the storage battery and the
The base of the first transistor is connected in series with the diode F of the transformer, and the base of the first transistor is connected to the winding end of the secondary winding of the transformer through the series connection of the feedback capacitor and the feedback resistor,
Also, the base of the first transistor is connected via a resistor to one of the switching section electrode terminals of the first transistor, and the base of the second transistor is connected to the first resistor, and the base of the second transistor is connected to one of the switching section electrode terminals of the first transistor. In a power supply circuit for supplying a current to a storage battery from an alternating current or direct voltage source of variable voltage value, one of the switching section electrode terminals of which is connected to earth potential or reference potential, a first transistor (1 ) is connected to the switching section electrode terminal of the second transistor (2) via the second guide (11). source circuit. the switching section electrode terminal of the transistor (2) and 3. a clocked inverter of the blocking type inverter connected in series with the primary winding of the blocking type transformer or the switching section of the first transistor and the first resistor; Secondary winding or storage battery and first diode-1
and the base of the first transistor is connected to one winding end of the secondary winding of the transformer through a series connection of a feedback capacitor and a feedback resistor;
the base of the transistor is connected via a resistor to one of the switching section electrode terminals of the first transistor, and the base of the second transistor is connected to the first resistor;
In a power supply circuit for supplying current to a storage battery from an alternating current voltage source or a direct current voltage source with a variable voltage value, in which one of the switching section electrode terminals of the second transistor is connected to a ground potential or a reference potential. 1 transistor (1
) is connected via a second diode (11) to the switching section electrode terminal of the second transistor (2), which is connected to the base-collector section of the first transistor (1). The first resistor connected in parallel consists of two individual resistors (61, 62), the connection point of the two individual resistors is connected to the can-P of the Zener diode (section 2), and the anode of the Zener diode is - A power supply circuit characterized in that the opening side terminal is connected to ground potential or reference potential.

Claims (1)

[Claims] - 1. A clock-controlled Blockkinder type inverter, which is connected in series with the primary winding of the transformer of the blocking type inverter or the switching section of the first transistor and the first resistor. The secondary winding of the transformer n1 is connected in series with the accumulator and the first diode p, and the base of the first transistor is connected to the secondary winding of the transformer through the series connection of the feedback capacitor and the feedback resistor. The base of the first transistor is connected to one end of the winding through a resistor.
connected to one of the switching section electrode terminals of the transistor nl
Furthermore, the base of the second transistor is connected to the first resistor, and one of the switching section electrode terminals of the second transistor is connected to earth potential or a reference potential, an alternating current voltage source with a variable voltage value. Alternatively, in a power supply circuit for supplying current from a DC voltage source to an accumulator, the base of the first transistor (1) connects via the second diode (11) to the switching section electrode of the second transistor (2). An electronic power supply circuit, characterized in that it has a clock-controlled blocking inverter, the primary winding of which is connected to the switching section of the first transistor and the switching section of the first transistor. The secondary winding of the transformer is connected in series with a resistor of n1, the secondary winding of the transformer is connected in series with a storage battery, a battery and a diode of the first nl and the base of the first transistor is connected in series with a feedback capacitor and a feedback resistor. Connected to one winding end of the secondary winding of the transformer through -rt
<Also, the base of the first transistor is connected to one of the switching section electrode terminals of the first transistor via a resistor, and the base of the second transistor is connected to the first resistor, n1 of the second transistor. one of the switching section electrode terminals of the transistor is connected to earth potential or a reference potential,
In a power supply circuit for supplying current to a storage battery from an AC voltage source or a DC voltage source with a variable voltage value, the base power of the first transistor (1), the second diode (11)
is connected to the switching section electrode terminal of the second transistor (2) via
The first resistor connected in parallel with the base-collector section of the circuit consists of two individual resistors (61, 62), and a Zener diode 1' (12) is connected to the connection point of the two individual resistors. n1 A power supply circuit characterized in that the anode side terminal of the Zener diode is connected to an earth potential, a potential, or a reference potential.