JPH01103161A - Power supply - Google Patents

Abstract

PURPOSE:To supply stable output by providing a Zener diode to detect the rise of the output voltage of a transformer and controlling base current of transistors by this detection output. CONSTITUTION:A power supply is constituted of a full-wave rectifying circuit Re, a smoothing capacitor C1, a pair of split capacitors C2-C3, a pair of transistors(Tr)Q4-Q5, a saturable transformer T and etc., and the power is supplied to the load L. A secondary coil N2 of this saturable transformer T grounds a center tap CT, and at the same time, the first rectifier diode D1 and the second rectifier diode D2 are connected. Zener diode ZD is provided to detect the collector output of the first TrQ1, and the second TrQ2 and Q3 are driven by TrQ1. Thereby, when the output voltage of the saturable trans former T rises due to the rise of supply voltage, etc., the Zener diode ZD detects it and cuts off the base current of TrQ1 and Q2, and keeps the supply voltage to the load constant.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) *ia, J:o Field of Application The present invention is directed to an IC source circuit employed in a load drive circuit such as an IE5 IC camera.

In the conventional battery photoelectric device disclosed in Japanese Patent Publication No. 58-42696, a series circuit of a pair of divided capacitors and a series circuit of a pair of transistors are connected in parallel to the rectified output terminal of a commercial power supply, and a series circuit of a pair of transistors is connected in parallel to the rectified output terminal of a commercial power source. An Ikku coil of a saturable transformer is inserted between the connection points, and the output of the secondary coil is used to photoelectrically charge the battery. An eight-bridge inverter is disclosed having a configuration in which a resistor t is connected in parallel to a capacitor + t- between each of the feedback coils, the intermediate point of the base resistor P, and the intermediate connection point of a pair of divided capacitors. ing. This flK
Since the load in the converter is a battery, it is saturated and therefore no compensation is provided for fluctuations in the power supply voltage.

However, if there is a driving load such as a motor on the second order 11 of the saturable transformer, there is a problem that this load cannot be driven stably due to output fluctuations.

Q9 Problem to be solved by the invention The problem to be solved by the invention is that in a power supply device using an eight-bridge inverter, the
The aim is to always supply stable output to the load.

) To the means to solve the problem - Fubridge inverter circuit t - The center tap t of the secondary coil of the saturable transformer that constitutes is grounded, and the first diode and the emitter and collector of the transistor are connected in series to one end of it. Then, a 42 diode is connected to the other end of one of the secondary coils, and this g2 diode is connected to the other end of the secondary coil.
Connect to the collector of Run Lister and the #! A load is connected to the connection point between the two diodes and the transistor, and a Zener diode is provided to detect an increase in the output voltage of the transformer, and the base current of the transistor is controlled by the detected output of the Zener diode.

(e) When the output voltage of the saturable transformer increases due to an increase in the power supply voltage or a decrease in the load, the Zener diode detects the increase, cuts off the current through the base of the transistor, and causes the base to open again due to the decrease in output voltage. The voltage supplied to the load is maintained approximately constant through on/off operation based on the detection signal of the Zener diode of the transistor.

(F) Additional Examples Hereinafter, a power supply device 11t of the present invention will be described in detail based on an example shown in the drawings.

Figure 1 is an implementation circuit diagram of the power supply device of the present invention), in which (R) is a full-wave rectifier circuit, and its AC input terminal is connected to the commercial power supply (AC) via a resistor (R5). ). A smoothing capacitor (C1) and a pair of divided capacitors f are connected to the DC output terminal (PI) CP of the full-wave rectifier circuit (Re).
The series circuit of (Cx) (Ca), the -11 transistor (Q4) (Q series circuits are connected in parallel), and the intermediate connection point (R5) (R4) of each series circuit are saturable. A primary coil/E(N 1 ) of the transformer is inserted.

This transformer has a 2vc coil (N) magnetically coupled to the primary coil (Nl) and a pair of feedback coils (N3) (N
4), one end of each feedback coil (Nil) (N4) is connected to the base of each transistor (Q4 and Q5), and the other end of each feedback coil (Nil) is connected to the base of each transistor (Q4) through the base resistor (R6) (87). Connected to the emitter of (Ql).Each feedback coil (N3) (N4) and base resistor (R6) (R7)
Capacitors (C4) (C5) are connected between each intermediate point (P5/P6) and the intermediate connection point (Pg), respectively.

On the other hand, the secondary coil (N is the center tap (CT) t-grounded of the #regular saturation transformer ■, and the - end is connected to the first!
! Diversion diode (Di) and jl! l transistor (
Ql) is connected in series with the emitter and collector of the secondary coil, and a second rectifying diode is connected to the other end of the secondary coil.
A load CEj is connected to the collector of the Tokun V star (Ql), and to the connection point (P7) between the collector of the two diode CD (CD) and the collector of the run lister (Ql) (ZD). A Zener diode to detect the collector output of the Tokunristor (Ql) and a resistor (R4)
and (R5) constitute a series circuit, and the resistor (R5
) t-grounded.

The base of the first transistor (Ql) is grounded through a series circuit of the collector and emitter of the second transistor (Q2) and a resistor (R),
The base of 2) is connected to the front cil diode (D1) through the resistor (Elf) t-. A third transistor is connected to the midpoint (R9) between the base of the run lister (Q2) and the resistor (R1), and its emitter is grounded, and the resistor (R2) is connected between the core emitters. It is interposed.

In the power supply device having the above configuration, when a commercial Elf source (AC) is connected to the full-wave rectifier circuit (Re), current flows through the series circuit of the base resistor C86) < R7), and each pace resistor (R6) Each transistor (Q4) (Ql) attempts to conduct due to the voltage drop across (R7), but one transistor becomes conductive due to variations in the components of these transistors (Q4) (Ql) and the n-th generation base bias circuit.

For example, if this is a transistor (Q4), the light IE of the split capacitor f(Cz)! The load is this transistor (Q4
), and the primary coil (N1), while the split capacitor (Cs) is directly discharged from the output terminal (P1) through the transistor (Q4) and the primary coil (N1). When current is applied from point (R4) to point (R5) of the primary coil (N1), a voltage is induced in one feedback coil (Ns) in the direction of further biasing the transistor (Q4), and the voltage in the other feedback coil (Ns) is The reverse bias voltage of the transistor (Q5) is induced in the feedback coil (N4).Therefore, the transistor (Q4) is conductive and <Q5) is cut off, and 2v<a positive half wave is applied to the coil (N2). Output occurs.

When the primary coil (N1) is excited and the core of the transformer is magnetically saturated, the magnetomotive force of this core disappears, and each feedback coil (Ns) (N4) receives a voltage in the opposite direction. is induced (ns ) One of the runlisters (Q4) is cut off and the other (Q5) is conductive. Therefore, split condan+(
Ci) photoelectric! The load a is discharged through the primary coil (N1) and the transistor (Q5), and the split capacitor (fccz)
is photoelectronized from the outflow blade end (Pl) through the coil (N1) and transistor (Q5), and the primary coil (Nl) is excited in the direction of (R4) from the point P (P), and the voltage is 2v. <Negative half-wave output is applied to the coil (N).

Similarly, when the core of transformer ■ becomes saturated, the conducting transistor changes), positive half-wave output and negative half-wave output alternately appear in the secondary coil (N2), and diode (D
i) The rectified full-wave output is supplied to load 0 via (D2).

As mentioned above, when voltage is generated in the second coil (N2), 1
Resistor (R1) (R3) t-through transistor (Q2)
The pace [flow n, M) 2ysis1CQ2) becomes conductive. Then, a current t flows from the base of the transistor (Ql) to the collector of the transistor (Q2), and this transistor (Ql) becomes conductive, and a negative current flows from the diode (Dt) to the collector of the transistor (Ql). A drive 11E flow is supplied in the FI direction.

For example, the voltage of commercial power supply (AC) is 100V to 120V
or the load 0 decreases, the output voltage of the secondary coil increases, and the Zener diode (ZD)
When the threshold voltage of is exceeded, a pace current is supplied to the transistor (Q5) through the resistor (R), and this transistor (Q3) becomes conductive.Therefore, the base potential of the transistor (Q) decreases and the transistor (( C) blocks the
The base current of the transistor (Q1) is cut off and this transistor (Ql) is made non-conductive.

As described above, as the Zener diode (ZD) repeats conduction and non-conduction, the transistor (Ql) becomes conductive and
The voltage supplied to the load is suddenly reduced by repeatedly disconnecting.

Figure 2 shows the voltage waveform applied to load 0 in the above dog example. ), the middle line in the figure shows the case where the voltage generated in the primary coil (hereinafter referred to as primary voltage) is 100V, and the dotted line is 12
The case of 0V is shown. In this way, the primary voltage is 120
In the case of V, the voltage applied to the load is higher than in the case of 100'/, but since the Zener diode conducts every lf cycle and the top of the waveform is cut off,
Compared to the case where the cfl does not have a voltage adjustment means, the average voltage is lower and cannot be kept within the allowable range of the load Ω.

As shown in Figure 3, the change characteristic of the lit pressure with respect to the 1'vcIE pressure has conventionally changed from the voltage AC (when the primary voltage is 100V) to the voltage C
(When lvc1c pressure is 120V), whereas -
As shown by the dotted chain line, (li! n = KK pressure 120 Vl 102 vctfB is B < C71 134
Satisfied the 1st section, 5! In terms of quality, there is little negative impact on load direction.

In the N1 diagram, the output fI of the second diode (D2)
llf: Connected to the emitter side of the transistor (Ql) n
For example, in FIG. 2, the head of the dotted voltage waveform can be cut off every half cycle, so the
Although it is possible to reduce fluctuations in the voltage, the time during which current is applied to the transistor (Ql) is doubled, which significantly increases the temperature of the transistor (Ql), which is undesirable.

(G) Effects of the Invention The present invention is as described above. The emitter and collector of the transistor are connected in series, and an M2 diode t'' is connected to the other end of one of the secondary coils, and this I'12 diode is connected to the collector of the tm period transristor, and the second diode and the transistor are connected. A load is connected to the connection point with 'Hi!', and a Zener diode is provided to detect the rise in the output voltage of the transformer, and the detection output of the Zener diode controls the flow at the base of the transristor a. The advantage of controlling only the output of one diode connected to the coil and reducing the drop in a due to the voltage drop of the transistor by half is tl)
A stable output can always be supplied to the load.

[Brief explanation of the drawing]

FIG. 1 shows the circuit diagram of a power supply according to the present invention, FIG. 2 shows a comparison of voltage waveforms applied to a load, and FIG. M3 shows a custom comparison of changes in secondary voltage with respect to 1vc1 and pressure. ■...Saturable transformer, CDI)...First diode, (Ql)...Transistor, (D2)...m2
Diode, mortar...load, <ZD)...zener diode.

Claims (1)

[Claims] (1) The center tap of the secondary coil of the saturable transformer constituting the half-bridge inverter circuit is grounded, and the first diode and the emitter and collector of the transistor are connected in series to one end of the center tap, and the other end of one of the secondary coils is connected in series. second to
a second diode is connected to the collector of the transistor, a load is connected to the connection point between the second diode and the transistor, and a Zener diode is provided for detecting an increase in the output voltage of the transformer. , A power supply device characterized in that a base current of the transistor is controlled by a detection output of the Zener diode.