JPS6146177A - Switching control type power source circuit - Google Patents

Abstract

PURPOSE:To use an inexpensive switch element which has small current capacity by interrupting a starting current when a power source OFF control signal is input, and stopping the operation of an error detector to cut off a switching transistor. CONSTITUTION:A power source circuit is composed of an input rectifier 1 having a bridge type rectifier and a smoothing condenser, a starting current controller 2, a blocking oscillator 3, a converter transformer 4, a switching controller 5, an output rectifier 5, an error detector 7, a remote control signal input unit 8, and an auxiliary power source 9. When a power source OFF control signal is input, a starting current to the base of a switching transistor TR5 is shut off by switching transistors TR1, TR2, the operation of the detector 7 is stopped by switching transistors TR10, TR11 to cut off a switching transistor TR5.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a switching control panel power supply circuit used as a power supply circuit for various T9C devices and a power supply for charging NiCd batteries and the like.

P) Conventional technology Switching control type power supply circuits include, for example, JP-A-58-
No. 17597 is a blocking oscillation type and has a turn-off timing control system.

By the way, when turning on and off such a switching control type power supply circuit using a remote control signal,
Conventionally, alternating current or direct current input to a power supply circuit was directly interrupted and interrupted by a relay or the like.

However, since a large current comparable to the load current flows through the input line to the power supply circuit, this method necessitates the use of expensive switching elements such as relays with large current capacities, as described above. has the disadvantage of high power consumption because it requires a large drive current.

(c) Problems to be Solved by the Invention The present invention takes the above-mentioned points into account, and makes it possible to easily turn on and off a switching control type power supply circuit by using a switching element with a small current capacity, low cost, and low power consumption. I'm trying to make it possible to turn it off.

B) Means for Solving the Problems The present invention provides a switching controlled power supply circuit in which a blocking oscillator circuit is constructed of a switching transistor and a comparator transformer connected in series with respect to a DC input.
A first switch means responsive to a power on/off control signal is provided in the supply path of the starting current from the DC input line to the pace of the switching transistor, and a first switch means is provided in response to a power on/off control signal, and the fcK output output movement taken out from the transformer is detected and the switching This configuration is such that the error detection section that controls the transistor is provided with a second switch means that responds to the control signal.

(E) Effect With the above configuration, the starting current is cut off by the first switch means when a power-off control signal is input, and
By means of the second switch 1)? #The operation of the error detection section is stopped, the switching transistor is cut off, and the power supply circuit is kept in the off state.

(f) Embodiment [Structure] Figure 1 shows an embodiment of the present invention. The embodiment can be roughly divided into an input rectifier section (1) including a bridge type rectifier circuit and a smoothing capacitor, and a starting current control section (2).
, a blocking oscillation section (3), a converter transformer (4), a switching control section (5), and an output rectification section (
6), error detection section (7), remote control signal input section (8), and auxiliary power supply circuit (9).
).

The starting current control section (2) connects a switching transistor (TR5) from the output line (Ll) of the input rectification section (1).
), the transistor ('I'R1) (TR2) and a reverse current blocking diode (Dl) are provided to supply and cut off the starting current Is to the pace of
A second photocup, which will be described later, is connected to one (R2) of the pace bias voltage dividing resistors (R1) and (R2) (1).

The blocking oscillator (3) basically connects the input winding (N 1 '') of the converter transformer (4) to the output line (Ll) of the input rectifier (1). Connect the collector-emitter of the TRs in series with the collector current detection resistor (R11),
In addition, the tertiary winding (N3) of the transformer (4) is connected between the pace emitter and the pace emitter of the transistor (TR5) via a pace current production circuit (SK). .

The switching control section (5) controls the tertiary winding (Na
) between the diode (D3) and capacitor (C
The DC voltage obtained by 1) is the resistance (R6) (R7) (R
8) is applied to the pace, and the voltage generated in the collector current detection resistor (R11) and the turn-off capacitor (C2), respectively, is added to the emitter and applied. It includes a transistor (TR4) that turns on and off in response to the transistor.

The output Wl flow section (6) is a converter transformer (4)
The first rectifying and smoothing circuit (6A) installed between g and 8 of the output winding (N2) of At the same time, a negative voltage is obtained at the 0 point by a second rectifying and smoothing circuit (6B) provided between h and 1 of the winding (N2).

The error detection section (7) is basically a differential pair transistor (TRs) that detects a variation in the load current IbIr - the current IO which flows through the first rectifying and smoothing circuit (6A) and has a substantially equal magnitude. (TRy)
A) and a second error detection circuit (7B) equipped with a transistor (TRs) that detects fluctuations in the DC output voltage ■0 obtained at the output terminal ('I'1) (T2),
The respective detection outputs of the first and second error detection circuits (7A) and (7B) are provided to the above-mentioned switching control section (5) by a first photocut λα■ provided in common.

The remote control signal input section (8) has a pace of resistance (R3).
2), a transistor (TI-9) connected to the control terminal (T3) for switching operation, and a second photocoupler driven by this transistor. Furthermore, the “high” and “low” remote control signals applied to the control terminal (T3) are transmitted to the error detection unit (7).
It is also applied to the pace of the detection operation stop transistor (TR1o) inside.

The auxiliary power supply circuit (9) includes a commercial AC step-down transformer (9A), a bridge rectifier circuit (9B), a smoothing capacitor (C6), and a simple constant voltage circuit ( 9C), and its DC output voltage is connected to the error detection section (7C) through the line (L5).
) is used as an operating power source.

〔motion〕

An embodiment of the present invention is generally configured as described above.Next, its operation t-(I) ON/OFF operation of the switching transistor in a steady state; (1) output stabilization control by the error detection section; Action, (III)! The explanation will be divided into three parts: power on/off switching operation using the J remote controller signal.

(I) ON/OFF operation of the switching transistor In the steady state, the switching transistor (T
When RY) is turned on (the principle of its operation will be explained later), a current If (Fig. 2 (B)) flows through this transistor and the input winding (N1), and this current Ii causes E
A negative voltage is generated at the point that increases over time. Here, during the off-period before the switching transistor (TR5), the turn-off capacitor (C2) is charged with the polarity IC shown in the figure by the current r flowing from one end (i) of the tertiary winding [N3]. . And the transistor (
The emitter of TRs), that is, point M, has the potential of point E with respect to the fin (L3) and the potential of the capacitor (02
Since the sum 1' corresponds to 6 potential 3 VM in Fig. 2 (1 construction), this potential VM is the switching transistor (TR
5) In the on period, it decreases over time (the negative value increases)
I will go there.

On the other hand, a resistor (R
6) The connection midpoint (N) between (R7) and (R8) connects the voltage between both ends (i) and (k) of the sixth winding (N3) to the diode (D
3) and the line obtained by rectifying and smoothing with a capacitor (C1) (
A negative potential (VN in FIG. 2 (1)) is obtained by dividing the DC voltage between L3 and L4. Therefore, when the potential of the previous point M falls below the potential of the N point, the transistor 10 (
'I'R3) is turned on and (TR4) is also turned on,
As a result, the turn-off capacitor (C2) → the collector current detection resistor (Rlt) → the emitter-base of the switching transistor ('I'R5) → the control transistor (TR4) → the resistor (RIO) → the above capacitor (C
A reverse bias current flows through the path 2), and the switching transistor (TRY) is turned off. This transistor (TR5) is then held in the off state by the reverse voltage (FIG. 2(F)) between terminals (i) and (j) of said winding (N3) until it is then turned on again. Ru.

Next, the off-period ζ of the switching transistor (TRs) is caused by resonance operation due to the inductance and distributed capacitance of the input winding (N1), and when this resonant current reverses in the direction of the current Ii, it causes the winding (N3 ) terminal (
Since a positive feedback current If (see the ON period in FIG. 2 (E)) flows from j) through the path shown in the figure, this positive feedback operation turns on the transistor (TR5), and this on state then causes the above-mentioned operation. It lasts until it is turned off again. Then, due to the on/off operation of the switching transistors (TRs), the range between g and h of the output s line (Na) of the converter transformer (4),
A rectangular wave voltage as shown in Fig. 2 (II) appears between 1 and 2, and the voltage during the OFF period is the voltage between the 1st and 2nd rectifying and smoothing circuits (6A).
(6B), it is taken out as a DC voltage.

(1) Stabilization control operation This operation will be explained assuming that the detection operation stop transistors (TR10) (TRu) in the error detection section (7) are not connected.

Now, if the impedance of the load α2 connected between the output terminals (TI) and (T2) of the output rectifier (6) is sufficiently large,
A constant voltage (vO) is obtained between the terminals (TI) and (T2). Then, in this case, the first rectifying and smoothing circuit (
The current (load current) IL that flows through the load (6) using the capacitor (C4) in the capacitor (C4) as a current source is small, so the current (load current) IL that flows through the detection resistor (R16) is low. ! , [current Ic (this current is approximately equal to the load current IL) is also small. Therefore, the above resistance (R
16) The potential of the line (R6) with one end (P) as a reference, that is, the pace potential of one of the differential pair transistors (TR7), is the ! of the Zener diode (ZDl). pressure to resistance (R1
7) The pace potential υ of the other (TR6) divided by (RlB) and the variable resistor (VRt) is also lower, so the transistor (TR7) is turned off. On the other hand, since the output voltage (VQ) of the rated value appears between the output terminals (TI) and (T2) at this time, the pace potential of the transistor (TRB) of the second error detection circuit (7B) is high<, This transistor is active.

Therefore, the output line (R5) of the auxiliary power supply circuit (9)
→ Diode (D9) → Resistor (R22) → Light emitting diode in the first photocoupler αα → Second error detection circuit (7
A current flows through the light emitting diode through the path from the transistor (TRs) to the Zener diode (Zn2) to the ground point in B), so that the light receiving transistor in the photocoupler αα exhibits six impedances in response to the current.

Therefore, when the output voltage (■0) rises from the state, the collector current of the transistor (TR8) increases and the impedance of the light receiving transistor decreases. The potential increases, and as mentioned above, the switching transistor (T
This shortens the on-period of R5) and lowers the output voltage.

Next, it is assumed that the impedance of the load (2) decreases significantly from the constant voltage control state. Then, the output terminal (Tl
) (T2) becomes very small, so the second
The transistor (TR8) of the error detection circuit (7B) is turned off. On the other hand, at this time, the load current If increases, so the current Ic flowing through the current detection resistor (R16) also increases, which causes the fin (R
6) voltage rises and the differential pair transistor (TR6) (
TR7) becomes active.

Therefore, this time the twin (R5) → Daioh)
(D9) → Resistor (R22) → First photocoupler uO)
Light emitting diode inside - Transistor ('I'R7) → Resistor (R21) → Capacitor (C5) → Resistor (R16) →
Current flows in the path of the ground point. Therefore, if the load current further increases from this state, the current of the light emitting diode increases in this case as well, and the impedance of the light receiving transistor in the first photocoupler αα decreases. As a result, the switching transistor (TR5)
Since the on-period of the load current IL is shortened and an increase in the load current IL is prevented, the maximum load current is limited to a predetermined magnitude, and therefore the stability obtained at the output terminals (Tl) (T2) 1m is For example, the PVDC output is custom-made as shown in Figure 6.

In addition, above, we have explained the case where the load impedance decreases from constant voltage operation to constant current operation, but conversely, there is no explanation for the case when changing from constant current operation to constant voltage operation. The same can be said.

(II) Power on/off switching operation First, control terminal (T3) is open or low level node I
Ha! J Mo:! Transistor (T
Rg) is turned off, so no current flows through the light emitting diode in the second photocup αυ, and the light receiving transistor in this coupler is cut off. This lick, the exit line (Ll) (R2) of the Kugata rectifier (1)
The unregulated DC voltage obtained during this period is divided by the resistors (R1) (R2) in the starting current control circuit (2), and the divided voltage is applied to the base of the transistor (TR1) via the resistor (R3). Since it is marked 7J, this transistor (TRI)
But the transistor (TR2) is off-nina. Therefore, the switching transistor ('I'R5
), the starting current Is does not flow from the line (Ll), and the blocking oscillation is not started.

Also, at this time, the transistor (TRtQ) for stopping the detection operation of the error detection section (7) is turned off (TR11).
is on (saturated). Therefore, a large current flows through the light emitting diode in the first photo coupler αα through the path of line (L5) → diode (D9°) → resistor (R22) → first photo cup → transistor (TRII) → ground point. , the light-receiving transistor in the coupler α becomes saturated.

As a result, the resistance (R6) in the switching control section (5)
) (R7) is short-circuited, the base potential of the transistor (TRa) with respect to the line (L3) is held at approximately 0■, and even if an extremely small current flows through the collector current detection resistor (Ru), The transistor (TRa) turns on.

Since the starting current Is is cut off in this way, the switching transistor (TR5) does not turn on,
Furthermore, even if -1 is turned on for some reason, the transistors (TRa) (TR4) are immediately turned on and the switching transistor (TRs) is turned off as described above, so the switching power supply is essentially in a stopped state, that is, the power is turned off. is maintained in the state of

When the control terminal (T3) becomes high level due to the remote control signal f, the transistor (TR9) is turned on. Then, line (L5)→line (L7)→resistance (R31)-*second photocoupler circle→transistor (T
A current flows through the light emitting diode number ζ in the above-mentioned foot cup circle through the path R9)→ground, and the light receiving transistor in this coupler is turned on. This allows the starting current control section (
Since both ends of the resistor (R2) in 2) are shorted, the transistor (TRI) is turned off and ('I'R2) is turned on. As a result, a state is reached in which a starting current Is is supplied to the switching transistor (T) L5) via this transistor (TR2) and the diode (DI'') to drive blocking oscillation.

However, when the first control terminal (T3) becomes high level, the transistor (TR1°) for stopping the detection operation is turned on and (TRII) is turned off, so this transistor (TRtl) is activated by the error detection section ( 7) and the operation of the switching control section (5) at all. Therefore, when the blocking oscillation section (3) is driven as described above, the error detection section (7) and the switching control section (5) perform the stabilization control operation explained in the previous section (1), and the load is reduced to 0z. It supplies a stabilized DC output with characteristics as shown in FIG. 3 above.

Note that the diode (DIO) provided in the output rectifier (6)
This is because when the DC voltage obtained from the constant voltage circuit (9C) of the auxiliary power supply circuit (9) decreases, the current to be passed through the light emitting diode in the first photo coupler αα is obtained from the output terminal (Tl). Therefore, the diode (Di) is off when the DC voltage is normal (slightly higher than the output voltage VO).

(g) Effects of the Invention As described above, according to the switching control type power supply circuit of the present invention, the R supply of the starting current from the DC input line to the base of the switching transistor and the turning on and off of the operation of the error detection section are performed. Since the power supply circuit can be turned on and off by using a transistor with a small current capacity and drive current as a switching element, it is possible to turn the power on and off using remote control signals, etc. at low cost, and the power consumption is low. There is an advantage to that.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a voltage/current waveform diagram of each part thereof, and FIG. 6 is a characteristic diagram of load current versus output voltage. (1)...Input rectification section, (2)...Starting current control section, (3)...Blocking oscillation section, (4)...Converter Trans, (5)-
... Switching control section, (6) ... Output rectification section, (7) ... Error detection section, (8) ...
...Remote control signal input section, (9)...Auxiliary power supply circuit, (TRI) (TR2)...Transistor corresponding to first switch means, (TRIO) (
TR1t)...Transistor corresponding to the second switch means.ヱ Procedural amendment (voluntary) June 12, 1985, Commissioner of the Japan Patent Office) 16 Indication of case Patent application No. 165313 of 1982 2 Title of invention Switching control type power supply circuit 3 Person making the amendment Relationship to the incident Patent applicant Name (188) Sanyo Electric Co., Ltd. 4, Agent Address 2-18 Keihan Hondori, Moriguchi City Contact information: Telephone (Tokyo) 53s-H1l! Nakagawa 5, stationed at the Center, Subject of amendment (1) Detailed explanation of the invention column (2) Figure 1 of drawings 6. Contents of amendment (1) Page 5, line 9 of the specification ``i'' for the eyes, ``j'' for the ``i'',
Correct to jrj1j. (2) “Resistance (R17) (R
18) Jwo'm anti(Rlg>(R19) J Gm
m positive t le. (3) ``Output winding (N)'' on page 10, line 12 of the same book
Correct it to "Output winding (N2) J. (4) Correct Figure 1 of the drawing" as shown in the attached sheet. that's all

Claims (1)

[Claims] (1) A power supply circuit in which a blocking oscillation circuit is configured with a switching transistor and a converter transformer connected in series with respect to a DC inflow line, and the switching transistor is controlled in accordance with fluctuations in the DC output taken out from the transformer. A first switch means responsive to a power on/off control signal is provided in a supply path for starting current from the DC input line to the base of the switching transistor, and a first switch means responsive to a power on/off control signal is provided to detect fluctuations in the DC output to switch the switching transistor. A second switch means that responds to the control signal is provided in the error detection section that controls the power-off control signal, and when the power-off control signal is input, the first switch means cuts off the starting current, and the second switch means cuts off the starting current. A switching control type power supply circuit, characterized in that the operation of the error detection section is stopped to maintain the switching transistor in a cut-off state.