JPS6132911B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a regulator circuit, and in particular to a DC-
This relates to a switching regulator circuit using a DC converter.

In such a type of switching regulator circuit, a DC input voltage is converted into a rectangular pulse-shaped AC voltage using a switching element and a transformer, and the AC voltage is rectified to obtain a desired DC voltage. It is. Furthermore, in recent years, so-called PWM switching regulators, which have good efficiency by varying the pulse width of the above-mentioned pulsed AC voltage according to load conditions, have been used as high-speed switching regulators for audio equipment.
Used in Fi amplifiers, etc. however,
Such a circuit has the disadvantage that its structure is complicated and expensive.

An object of the present invention is to improve this type of regulator circuit, and to provide a highly efficient regulator circuit with a simple circuit configuration.

The present invention will be explained below with reference to the drawings.

FIG. 1 is a circuit diagram showing an embodiment of the present invention,
Transistors Q ₁ and Q ₂ as switching elements are connected in series to both ends of the primary winding L ₁ of the converter transformer T, and the common emitter connection point is grounded. The input DC voltage +B is applied to the base of each transistor through the primary windings L ₂ and L ₃ and further through the resistor R ₁ , and both windings
The common connection point of L ₂ and L ₃ is grounded via resistor R ₂ . Further, a voltage +B is applied to the middle point of the primary winding _L1 .

The middle point of the secondary winding L ₄ of the transformer T is grounded, and the AC voltage in the form of a rectangular pulse wave whose frequency is proportional to the input voltage is applied to both ends A-A' of the secondary winding _{L 4} . The circuit configuration is well known and the explanation of its operation will be omitted.

Silicon controlled rectifying elements (hereinafter referred to as SCR) 1 and 2 are provided as shown in the figure to perform full-wave rectification of the alternating voltage across A--A' of the secondary winding _L4 . That is, the anode of SCR1 is connected to terminal A, the cathode to the terminal of smoothing capacitor _C1 in the next stage, and the anode of _SCR2 to terminal A', and the cathode to the terminal of smoothing capacitor _C1 . The smoothed output of capacitor C ₁ is supplied to load 3 .

Furthermore, in order to create a control voltage to be applied to the control gate electrodes of SCRs ₁ and 2, diodes 4 and 5 are used for full-wave rectification of the alternating current voltage at the winding terminals A-A'.
A resistor R ₃ and a smoothing capacitor C ₂ are connected to smooth this rectified output, and a voltage regulator diode 6 that makes this smoothed output a constant voltage is provided in parallel with the capacitor C ₂ . .
This constant voltage output is connected to the SCR via resistors _R4 and _R5 .
The configuration is such that the voltage is applied to each of control terminals 1 and 2, respectively.

The operation of the circuit shown in FIG. 1 will be explained using FIG. 2. Figure 2 a shows the voltage waveform between both ends A-A' of the secondary winding, and b shows the current waveform of SCR1.
The dashed dotted line is the current waveform of SCR2, and C is the terminal voltage waveform of smoothing capacitor _C1 .

First, before time t ₁ (see Figure 2), capacitor C ₂ is charged, and its smoothed output voltage Vr
is held approximately constant, and the capacitor
C ₁ is the voltage caused by the SCR that was conducting before the relevant time t ₁ .
Assume that it is charged to V ₂ . In such a state, at time t ₁ , a positive voltage V ₁ is applied to the anode of SCR 1.
is applied, but if the difference between the charging voltage V ₂ of the capacitor C ₁ and the gate voltage Vr is not more than 0.7 V (gate-cathode voltage of SCR), SCR 1 will not conduct. Here, while SCR1 is non-conductive, smoothing capacitor _C1 is discharged via load 3 with a time constant τ determined by load 3. When the difference between this terminal voltage and the gate voltage Vr becomes the above-mentioned 0.7V or more, the SCR1 becomes conductive for the first time. This state is the period t ₁ to t ₂ , and during this period the terminal voltage V ₁
is rectified by diode 4 and connected to capacitor C ₂
The terminal voltage of is refreshed to Vr. At time t ₂
Since SCR1 turns on, the smoothing capacitor is charged again and rises to _V2 .

When the voltage between terminals A and A' is reversed at time _t3 , SCR1 is turned off and positive voltage _V1 is applied to the anode of SCR2. However, SCR2
The cathode voltage of , that is, the terminal voltage of capacitor C ₁ is V ₂ , which does not have a potential difference of 0.7 V or more with respect to Vr, so SCR 2 maintains an off state. Therefore, the terminal voltage V ₂ of the capacitor C ₁ is discharged by the load 3, and at the time t ₄ when the difference between this voltage and the gate voltage Vr becomes 0.7 V or more, the SCR 2 is turned on.

It can be seen that this operation is repeated corresponding to the period of the voltage waveform between the winding terminals A-A'. Here, the time t ₁ to _{t 2} or t ₃ to _{t 4} when both SCRs are non-conductive
The length of is determined by the magnitude of load 3. The reason is that when the load 3 becomes heavier, the discharge time constant τ of the capacitor C becomes smaller, and the voltage V ₂ becomes smaller than the gate voltage Vr.
It will fall below −0.7V faster and therefore
The on time of SCR is proportional to the weight and weight of the load. Also
When the SCR conducts, the cathode voltage is suppressed to a voltage 0.7V lower than the control voltage Vr, so the control voltage Vr is maintained at an approximately constant voltage by the diodes 4 and 5, the capacitor C ₂ , and the Zener diode 6. Therefore, the cathode voltage of the SCR, that is, the load supply voltage, is also suppressed to a constant voltage of Vr - 0.7V. In addition, the control voltage Vr is SCR1,
2 is off, high voltage across terminals A-A'
Since V ₁ is rectified and made into a constant voltage, the control voltage Vr can be higher than the output voltage (load supply voltage).

As described in detail above, according to the present invention, power is supplied to the load according to the load condition with a simple configuration, so the advantage is that efficiency can be improved and it is possible to obtain a roughly constant output voltage. There is.

In the above embodiment, a switching regulator circuit using a DC-DC converter method was explained, but a power supply output that generates a rectangular AC voltage waveform is directly applied between A and A' in FIG. It is clear that the circuit of the present invention is not limited to the switching regulator circuit, since the same effect can be obtained with any other circuit.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a waveform diagram explaining the operation of FIG. 1. Explanation of symbols of main parts, 1, 2...SCR,
4, 5...Diode, 6...Zener diode, _C1 , _C2 ...Capacitor, T...Transformer,
Q ₁ , Q ₂ ...transistor.

Claims (1)

[Scope of Claims] 1. A control rectifier that rectifies a predetermined alternating current voltage and has a control terminal, a smoothing means that smoothes the rectified output of the control rectifier and supplies it to a load, and a rectifier that rectifies the alternating current voltage and has a control terminal. A regulator circuit comprising a holding means for holding the voltage at a constant voltage, and applying the constant voltage to a control terminal of the control rectifying element to substantially constant the output of the smoothing means. 2. The holding means includes a rectifying element that rectifies the AC voltage, a capacitor that smoothes the rectified output of the rectifying element, and a constant voltage element that makes the smoothed output a constant voltage. A regulator circuit according to range 1.