JPS62216012A - Stabilized power supply device with high efficiency - Google Patents

Abstract

PURPOSE:To secure the high efficiency and also high responsiveness to the variation with a stabilized power supply device, by connecting a series regulator to the output side of a switching regulator and giving the feedback control to the switching regulator. CONSTITUTION:A series regulator 2 is cascaded to the output side of a switching regulator 1 and the AC input is first supplied to the regulator 1 for rectification and pulse width control. Then the AC input thus rectified and controlled is supplied to a load 3 after the control of voltage through the regulator 2. Here a feedback circuit 4 controls the regulator 1 so that the input voltage level of the regulator 2 is increased or decreased when the difference between the input and output voltage levels of the regulator 2 is reduced less or increased more than the prescribed drop voltage level respectively to attain the desired efficiency of conversion.

Description

[Detailed description of the invention] 9 ■ The present invention relates to a highly efficient stabilized power supply device.

Switching regulators and series regulators are generally used to stabilize the voltage supplied to electronic devices.

However, although switching regulators have high efficiency, their load response is slow, so ripple noise tends to remain in the output voltage, and series regulators have excellent ripple suppression performance, but have low conversion efficiency and are tolerant of input fluctuations. The problem is that the range is narrow.

1-Miko This invention was made in view of the above points, and aims to improve the stability of supply voltage and conversion efficiency against fluctuations in input voltage and load.

In order to achieve the above object, the present invention connects a dropper type series regulator to the output side of a switching regulator, detects the input/output potential difference of the series regulator, and performs feedback control of the switching regulator.

This is designed to keep the drop voltage in the series regulator approximately constant.

Hereinafter, a detailed explanation will be given based on one embodiment of the present invention.

FIG. 1 is a block circuit diagram showing an example of a highly efficient stabilized power supply device embodying the present invention.

1 is a switching regulator, which is a voltage stabilizing circuit that stabilizes the output voltage by controlling the pulse width of switching control elements such as transistors and SCRs (silicon-controlled rectifiers) inserted in the power supply circuit. It obtains DC output from a commercial power supply (AClooV),
A DC-DC converter may also be used.

Note that this switching regulator 1 receives external
! The output voltage is controlled by the I+ control signal.

2 is a dropper type (analog type) series regulator, which inserts a control transistor in series with the power supply circuit, detects the error of the output voltage with respect to the reference voltage, and feeds it back to the base of the transistor, so that the drop voltage can be converted into an analog type regulator. It is controlled by the formula.

This power supply device has a series regulator 2 connected in cascade to the output side of a switching regulator. AC input is first input to the switching regulator 1 for rectification and pulse width control, and then passed through the series regulator 2 to the load after adjusting the voltage. We are trying to supply it.

Furthermore, the control aBF of the series regulator 2 output terminal and the switching regulator 1! A feedback circuit 4 including an error amplifier is provided between the series regulator 2 and the output voltage Vo (V
i-Vo), and the switching regulator 1 is controlled by a feedback signal Vf according to the difference.

This feedback circuit 4 has a resistor R1*R for obtaining a voltage vi' proportional to the input voltage Vi of the series regulator 2', which is the output voltage of the switching regulator 1, as shown in FIG.
2 and resistors R3 and R to obtain a voltage Vo' proportional to the output voltage Vo of the series regulator 2.
4 and a voltage dividing circuit including a variable resistor VR, an error amplifier 5 which inputs the voltages vi' and Vo', and outputs a feedback signal Vf according to the difference therebetween, and its feedback resistor Rf.

Next, the operation of this embodiment configured as described above will be explained.

Input voltage Vi of series regulator 2 in Fig. 1
When the difference (Vi-Vo) between The feedback circuit 4 controls the switching regulator 1 by a feedback signal Vf according to the input/output voltage difference so as to lower Vi.
control.

The set value of this drop voltage can be adjusted by adjusting the variable resistor VR shown in FIG. Also.

The output voltage to the load is set using the reference voltage setting adjustment in series regulator 2! Performed by first baseman.

Therefore, according to this embodiment, the output voltage of the series regulator 2 can be substantially reduced, and at the same time,
The input/output voltage difference, that is, the drop voltage, can also be kept substantially constant at a desired value, and the loss in the series regulator 2 can be minimized.

Generally speaking, the efficiency of a switching regulator has little to do with the input/output voltage difference, but the conversion efficiency of dropper type series regulators deteriorates when the input/output voltage difference is large, so as mentioned above, this difference voltage can be used to adjust the desired conversion efficiency. By controlling it to a predetermined value necessary to obtain
High efficiency can be obtained.

Next, this highly efficient stabilization f! ! Third example of using the source device in the horizontal deflection circuit of a CRT display device
This will be explained with reference to the figures. Note that the same parts as in FIG. 1 are given the same reference numerals.

In this horizontal deflection circuit, first, the horizontal cylinder # circuit 5, which is composed of a PLL oscillation circuit, etc., inputs a horizontal synchronization signal transferred from the host side and generates a horizontal scanning signal, and the horizontal drive circuit S generates a horizontal scanning signal. A deflection current Ih having a sawtooth waveform is supplied to the deflection coil 7 in accordance with the supply voltage Vo from the stabilized power supply (output voltage of the series regulator 2) in accordance with the signal.

Note that the horizontal deflection width is determined by adjusting the output voltage Vo of the series regulator 2 and setting the current flowing through the horizontal deflection coil 7.

Also, the oscillation frequency of the switching regulator 1 is set to avoid beats with the horizontal deflection frequency.

Synchronization is performed at the horizontal deflection frequency or a frequency that is an integral multiple or a sub-integer of the horizontal deflection frequency, and the synchronization signal is supplied from the horizontal control circuit 5.

Generally, the load on the horizontal deflection circuit of a high-resolution CRT display device fluctuates at a high frequency of 60KH2 or more, so the loss fluctuates greatly due to the difference in input and output voltages of the stabilized power supply, causing heat generation.

This input/output voltage difference varies depending on input voltage fluctuations, horizontal deflection width, horizontal deflection coil inductance, etc., and the heat generation situation changes accordingly.

Conventionally, in order to maintain this margin, the input/output voltage difference had to be large, resulting in large losses.

However, according to this embodiment, the switching regulator 1. By using a stabilized power supply device consisting of a series regulator 2 and a feedback circuit 4, the difference between the input voltage Vi and the output voltage Vo of the series regulator 2 is fed back to the switching regulator 1 via the feedback circuit 4, as described above. Since the output voltage Vi of the switching regulator is controlled so that the difference between the input and output voltages of the series regulator 2 is kept at a substantially constant value, the loss in the series regulator 2 is reduced.

It can suppress fever.

In addition, by setting the oscillation frequency of the switching regulator 1 as described above, noise contamination on the image due to the beat between the horizontal deflection frequency and the oscillation frequency of the switching regulator 1 is eliminated, and stable and highly accurate horizontal deflection can be achieved with high efficiency. can be done.

Thus, the highly efficient stabilized mg device according to the present invention
This is particularly effective when used as a power supply device for a circuit whose load fluctuates at high frequencies.

As explained above, according to the present invention, by taking advantage of the advantages of a switching regulator and a dropper type series regulator, it has good responsiveness to input voltage and load fluctuations, high efficiency, and ripple suppression. It can provide a good high efficiency regulated power supply.

[Brief Description of the Drawings] Fig. 1 is a block circuit diagram showing an embodiment of the present invention, Fig. 2 is a circuit diagram showing a specific example of the feedback circuit in Fig. 1, and Fig. 3 is a block circuit diagram showing an embodiment of the feedback circuit of the present invention. CRT efficiency stabilization power supply device
FIG. 2 is a block diagram showing an embodiment used in a horizontal deflection circuit of a display device. 1...Switching regulator 2...Dropper type series regulator 3...Load 4...Feedback circuit 5...Horizontal control circuit 6...Horizontal drive circuit 7...Horizontal deflection coil Fig. 1 Figure 2

Claims (1)

[Claims] 1. A dropper type series regulator is connected to the output side of the switching regulator, and a feedback circuit is provided to detect the difference between the input voltage and the output voltage of the series regulator to feedback control the switching regulator, and to reduce the drop voltage in the series regulator. A highly efficient stabilized power supply device characterized in that the voltage is kept approximately constant.