KR0152598B1 - Power stabilization circuit having high frequency characteristic - Google Patents

Abstract

According to the present invention, a primary winding unit to which external power is supplied, a secondary winding unit for outputting an internal power supply voltage induced by the primary winding unit, and a light detected by detecting a change in voltage output from the secondary winding unit A power supply unit comprising an output voltage detector for emitting a light and a power stabilization circuit for controlling an operation of the primary winding unit by receiving an output of the output voltage detector. By improving the current supplied only to the feedback terminal to the power switching element of the power stabilization circuit, a large amount of current is supplied by the photo coupler and the switching element in a section where the voltage of the feedback terminal increases, The present invention relates to a power supply stabilization circuit with a higher signal frequency.

Description

Power stabilization circuit with high frequency characteristics

1 is a circuit diagram showing a power supply unit including a conventional power stabilization circuit.

2 is a circuit diagram schematically showing an internal circuit of a power switching unit constituting a power stabilization circuit.

3 is an operation waveform diagram of an internal circuit of a power switching unit constituting a power stabilization circuit.

4 is a circuit diagram showing a power supply unit including a power stabilization circuit according to the present invention.

5 is a waveform diagram comparing the frequency characteristics of the power supply stabilization circuit according to the prior art and the present invention.

* Explanation of symbols for main parts of the drawings

10: external power input unit 20: primary winding unit

30: secondary side first winding portion 40: secondary side second winding portion

50: output voltage detector 55: voltage detection IC chip

60, 60 ': power stabilization circuit 61: feedback control unit

62, 62 ': power supply switching unit 65: internal oscillation circuit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit for supplying a power supply voltage used in an electronic device, and in particular, converts an external power source of an AC component into a direct current power source required in the electronic device and simultaneously transforms and converts an external power source required by the internal circuit. The present invention relates to a power supply stabilization circuit having a high frequency characteristic that drives the transformer unit at a high frequency in order to reduce power consumption and to maintain the potential of the internal power supply voltage in a stable manner.

In general, the electrical energy generated at high pressure in the power plant is transformed and transferred to each home and factory. The voltage supplied above is an alternating voltage, and in order to drive various electronic devices used in the home or factory, It is changed and used as needed.

As the internal circuit of an electronic device is complicated and divided into various parts with different characteristics, the internally required voltage has a plurality of potentials, so the externally supplied power is variously transformed in the internal power supply unit.

1 is a circuit diagram showing a power supply unit including a conventional power stabilization circuit, which is transmitted through an external power input unit 10 and an external power input unit 10 to transmit an AC voltage supplied from the outside. A primary winding unit 20 for smoothing an external voltage and transferring it to an internal circuit, a secondary winding first side 30 for inducing a first internal power supply Vint1 supplied to the internal circuit, and an internal circuit Secondary winding part 40 which induces the supplied second internal power supply Vint2, and output terminal Vint1 of the secondary winding part 30 and the output terminal of the second winding part 40 which are secondary. An output voltage detection unit 50 connected between Vint2 and detecting the state of the output voltage, and a power supply stabilization circuit connected to the primary winding unit 20 to control the operation of the primary winding unit 20; It contains 60.

Looking at the configuration of the respective parts in more detail as follows.

First, the external power input unit 10 has a diode bridge structure, and the primary winding unit 20 is connected to the output node of the external power input unit 10 to lower the potential of the applied power. A capacitor component Cp connected between the resistor component Rp, the other node of the resistor component Rp and the ground voltage terminal, and smoothing the transferred AC power to a DC power source; and the capacitor component Cp; The transformer Rp is connected to a node to which the resistance component Rp is connected to accumulate energy for transforming.

The secondary side first winding part 30 includes a diode component D1 connected forward to a secondary side transformer coil L1 and an output terminal Vint1 at the transformer coil L1, and the output terminal Vint1 and a ground voltage terminal. Comprising a capacitor component (C1) connected between, the secondary side second winding portion 40 has the same structure as the first winding portion 30, only the number of turns of the transformer coil (L2) is different.

As mentioned above, the output voltage detection unit 50 is transformed to maintain the voltage applied to the internal circuit in a stable state, and output terminals of the first winding unit 30 and the second winding unit 40 on the secondary side. Compares the voltage change induced in (Vint1, Vint2) and delivers the result to the power supply stabilization circuit (60). Therefore, the configuration emits light having a different intensity depending on the amount of current flowing in the first resistance component R1 for properly dropping the output voltage of the second winding portion 40 and the resistance component R1. A first photo coupler PC1, a second resistance component R2 for appropriately lowering the output voltage of the first winding part 30, the first photo coupler PC1, and a second It consists of a voltage detection IC chip 55 connected to the resistance component (R1), the amount of current flowing through the first photo coupler (PC1) is determined by the first and second resistance components (R1, R2), The voltage detection IC chip 55 operates to change the current value of the second point 2 to which the first photo coupler PC1 is connected according to the amount of current at the first point 1 to which the resistor R2 is connected. The output voltage is detected using the transistor's current amplification characteristics.

On the other hand, the power stabilization circuit 60 shown in FIG. 1 includes a feedback control unit 61 including a secondary coil and a photo coupler for absorbing light internally again through the feedback control unit 61 and the feedback control unit 61. It consists of a power switch 62 for adjusting the operating speed of the primary winding 20 according to the amount of current delivered.

The feedback controller 61 includes a transformer coil L3, a diode component D3, a capacitor component C3, and the capacitor component C3 and the diode component D3 having the same structure as the secondary winding unit. A node connected between the node N1 and the feedback terminal F / B of the power switching unit 62 and operating by receiving light emitted from the first photo coupler PC1 of the output voltage detecting unit 50. 2 includes a photo coupler (PC2).

The power switching unit 62 operates the internal switching element Qsw in a section in which the potential of the feedback terminal F / B increases to the reference voltage Vref by the amount of current transmitted to the feedback control unit 61. One node of the transformer coil Lp is connected to the ground voltage terminal so that energy is stored in the transformer coil Lp of the primary winding unit 20, and a chip type is usually used.

2 and 3 illustrate a schematic configuration and an operating waveform of the power switching unit 62 manufactured in the chip shape, and the power switching unit 62 is connected to the internal oscillation circuit 65. The capacitor components C11 and C12 and the resistance components R11 and R12 connected in parallel with the capacitor components C11 and C12 are included.

As shown in FIG. 3 (b), the voltage applied to the capacitor C11 is charged for a predetermined time T1 so that the potential increases to 0.75V, which is the reference voltage Vref, and then discharges temporarily. The lowest potential state (0V) is maintained during T2).

Meanwhile, the voltage applied to the capacitor C12 is maintained at a constant potential (2.3 V) for a predetermined time T1 as shown in FIG. 3A, and the reference voltage (0.75 V) is induced to the capacitor C11. When the potential is lowered to 1V, the voltage rises again to 2.3V, and the state is maintained for a predetermined time T1. The voltage across the capacitor C12 instantaneously rises to 2.3V and the voltage across the capacitor C11 drops to the lowest state (0V) after rising to the reference voltage (0.75V) is not shown in FIG. (The voltage value may be set differently according to the characteristics of the power switching unit.)

In the waveform shown in FIG. 3B, since the resistance component R11 of the power switching unit 62 is connected to the feedback terminal F / B, the same waveform is also detected at the feedback terminal F / B. Accordingly, the switching element Qsw in the power switching unit 62 operates while maintaining a constant voltage (T1) in FIG. 3 (e) and maintains an off state in the period (.T2) where the voltage drops. .

The operation of the power supply unit shown in FIG. 1 will be described as a whole with reference to the operation characteristics of the above-described parts and the signal waveform thereof.

As shown in FIG. 3 (b), since the switching element Qsw of the power switch 62 is kept in the period T1 in which the voltage rises in the signal waveform, the primary winding unit at this time ( In the 20, energy is accumulated by the power delivered through the external power input unit 10, and when the switching element Qsw is turned off after a predetermined time T1 has elapsed, the primary winding unit 20 has accumulated. The energy moves toward the secondary winding, so that induced voltage is generated in the secondary transformer coils L1, L2, and L3, which charges the capacitors C1, C2, and C3 of the secondary winding.

After the predetermined time T2 in which the switching element Qsw is turned off has elapsed, energy is accumulated in the primary winding unit 20 again. At this time, the secondary winding unit capacitors C1, C2, and C3 ) Is discharged, the internal voltage is transmitted to the primary output terminals (Vint1, Vint2), at the same time the change in the output voltage is detected by the output voltage detector 50, the light is emitted from the photo coupler (PC1).

While the secondary side and the first and second windings 30 and 40 and the output voltage detector 50 are in operation, the power supply stabilization circuit 60 is also deactivated. In the feedback controller 61, the photo coupler PC2 is operated. ) Is operated by the light transmitted from the output voltage detection unit 50 to transfer the current discharged from the capacitor C3 to the feedback terminal F / B of the power switching unit 62. The potential gradually rises. When the potential of the feedback terminal F / B reaches the reference voltage Vref again, the switching element Qsw of the power supply switching unit 62 is turned off, and the energy accumulated in the primary winding unit 20 again becomes 2 Each will move to the secondary winding.

The operation made as described above is repeatedly executed while power is applied through the external power input unit 10, and the power stabilization circuit 60 is controlled by using a feedback characteristic to maintain a stable state of the power delivered to the internal circuit. The signal frequency of the feedback terminal (F / B) of) is slightly changed depending on the intensity of the light emitted from the output voltage detector 50 to maintain the stabilization of the power supply. However, since the frequency is usually 30 kHz or more, energy is transferred from the primary winding unit 20 to the secondary winding unit, and the energy is fed back according to the intensity of the energy delivered to the secondary side to adjust the energy transfer state again. Will be done.

In the above operation waveform of the power switching unit 62 driving the primary winding unit 20, that is, the longer the period during which the switching element Qsw is turned on, Since a large amount of energy is stored in the transformer coil Lp, when energy is transferred to the secondary side, a large amount of current flows through the secondary windings 30 and 40, resulting in increased power consumption and stability of the generated internal voltage. Will fall. Therefore, it is important to increase the waveform frequency of the feedback terminal F / B driving the power switching unit 62 so as to operate the power supply stabilization circuit 60 faster.

However, in the power stabilization circuit 60 shown in FIG. 1, since the current is supplied to the feedback terminal F / B only through the second photo coupler PC2, the feedback terminal F / B is connected to the reference voltage Vref. There is a slow bloc.

Accordingly, an object of the present invention is to implement a power supply stabilization circuit operating at a high frequency in order to improve the characteristics of the secondary winding unit outputting the internal power supply and to reduce power consumption.

In order to achieve the above object, the present invention improves that the feedback terminal in the conventional power supply stabilization circuit is supplied with current only by the second port coupler, thereby connecting the feedback terminal to the power supply switching element of the power supply stabilization circuit, The power supply stabilization circuit has been implemented to increase the signal frequency at the feedback terminal by supplying a large amount of current by the port coupler and the switching element in the period of increasing voltage.

Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the present invention.

Figure 4 shows a power supply unit including a power stabilization circuit according to the present invention, the rest of the parts except for the power stabilization circuit according to the present invention is the same as shown in Figure 1 the configuration and operation method of the power stabilization here Only the circuit will be described in detail.

The power stabilization circuit 60 ′ shown in FIG. 4 has a feedback control section 61 and a feedback terminal F / B connected to the feedback control section 61 having the same structure as that of FIG. A power supply switching unit 62 'connected to the emitter end of Qsw) is provided.

That is, the feedback controller 61 includes a transformer coil L3, a diode component D3, a capacitor component C3, and a phototransistor type second photo coupler PC2 whose operation is controlled according to the light intensity. . In addition, the power switching unit 62 'connects the peripheral pressure coil Lp to the ground voltage terminal in the manner of storing energy in the primary winding unit 20, and while the energy of the primary side is transferred to the secondary side. By disconnecting the transformer coil Lp from the ground voltage terminal, the switching element Qsw formed of the transistor structure and the operation of the switching element Qsw are internally operated to realize the transformer operation in the primary winding unit 20. It includes a feedback terminal (F / B) for receiving a signal transmitted from the feedback control unit 61 to control, the feedback terminal (F / B) is a second photo coupler (PC2) of the feedback control unit 61 ) And the transistor of the switching element Qsw having the transistor structure.

Therefore, the energy accumulated in the primary winding unit 20 is transmitted through the transformer coil L3 of the feedback control unit 61, and the switching element Qsw in the power supply switching unit 62 'operates by an internal signal. When the electric potential of the emitter terminal of the switching element Qsw and the feedback terminal F / B connected to the second photo coupler PC2 starts to increase, the switching element Qsw and the second photo coupler PC2 are started to increase. Since the current is supplied through the feedback terminal F / B, the reference voltage Vref is reached in a faster time than in the related art.

FIG. 5 shows signal waveforms of a feedback terminal in the conventional power stabilization circuit 60 shown in FIG. 1 and the power stabilization circuit 60 'according to the present invention shown in FIG. The voltage rising period t1 'in the waveform of the present invention shown in FIG. 5B is shorter than the voltage rising period t1 in the conventional waveform shown in (a), while the voltage remains at its lowest state. Since the period t2 in which the switching element of the power switching unit does not operate is constant, the waveform of the present invention shown in FIG. 5 (b) operates at a higher frequency.

As described above, when the signal frequency of the feedback terminal in the power stabilization circuit according to the present invention is increased, the entire power supply unit shown in FIG. 4 becomes faster in operation than in the prior art. And if the frequency f goes up

Lp ∝ 1 / f, Np ∝ Lp

As a result, the reactance Lp and the number of windings Np of the main transformer coil of the primary winding unit 20 are reduced, resulting in miniaturization of the transformer of the power supply unit, thereby reducing the cost. .

In addition, as the frequency increases, the amount of current flowing to the secondary side decreases as compared with the conventional one, and therefore, even when the first power supply voltage Vint1 having a high potential is outputted, the resistor R2 must withstand a large current. Compared with the low current flow, the resistance (R2) and the wattage (wattage) can be reduced.

Claims (4)

A primary winding unit to which an external power supply is supplied, a secondary winding unit for detecting an internal power supply voltage induced by the primary winding unit, and a change in voltage output from the secondary winding unit to detect and emit light. A power supply unit including an output voltage detection unit and a power stabilization circuit for controlling the operation of the primary winding unit in response to the output of the output voltage detection unit, the switching for connecting or disconnecting the primary winding unit to the ground voltage terminal. An internal circuit for internally outputting a device, a signal for controlling the operation of the switching device, and a feedback terminal for receiving a signal fed back from the output voltage detector and transferring the received signal to the internal circuit, thereby controlling the operation speed of the switching device. The driving power is output by receiving the energy of the primary winding through the power switching unit and the transformer coil Feedback is composed of a drive stage and a feedback stage connected to an output node of the drive stage, the operation of which is controlled according to the intensity of light emitted from the output voltage detector to transfer the current supplied from the drive stage to the feedback terminal of the power switching unit. And a control unit, wherein a feedback terminal of the power switching unit is connected in common to an output node of a switching element of the power switching unit and a feedback terminal of the feedback control unit. The power stabilization circuit of claim 1, wherein the power switching unit is implemented as a chip including each part. The driving unit of claim 1, wherein the driving stage of the feedback control unit outputs a transformer coil for outputting an induced voltage when energy stored in the primary winding unit is transferred, and for charging energy transferred by the induced voltage of the transformer coil. And a capacitor component connected between a node and a ground voltage terminal, and a diode component forwardly connected from the transformer coil to an output node which is one node of the capacitor component. The method of claim 1, wherein the feedback stage of the feedback controller is connected between the output node of the driving stage and the feedback terminal of the power switching unit, characterized in that it comprises a photo coupler whose operation is controlled in accordance with the intensity of light absorbed. High frequency power supply stabilization circuit.