JPH03226232A - Dc power supply device - Google Patents

Abstract

PURPOSE:To reduce power loss remarkably by a method wherein the input curcent of an AC power supply is converted by a voltage reducing capacitor into current delayed in the phase thereof and is supplied to a voltage smoothing capacitor. CONSTITUTION:When the input voltage of the point A of an AC power supply 9 is higher than the voltage of another point B, an electric current having a phase delayed with respect to the phase of a power supply voltage is conducted through both circuits of a constant voltage diode 3 and a voltage smoothing capacitor 5 as well as an auxiliary diode 4 by the operation of a voltage reducing capacitor 2, then, the current is conducted through the point B through the voltage reducing capacitor 2 and a noise blocking resistor 1. In this case, a voltage V5, impressed on the voltage smoothing capacitor 5, becomes the voltage of V3-V4, in which the forward voltage drop V4 is subtracted from the voltage V3 of the constant voltage diode 3. After the voltage smoothing capacitor 5 is charged to the voltage V5, the current is conducted through the constant voltage diode 3.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a DC power supply device for household equipment equipped with an electronic control circuit such as a microcomputer.

2. Description of the Related Art In recent years, devices equipped with microcomputers have been used, and in order to supply low-voltage DC power to the control circuits, commercial AC power is rectified and stepped down.

Conventionally, this type of DC power supply device had a configuration as shown in FIG. That is, the operation of the device 8 is controlled by the control section 6 connected to an operation instruction controller (not shown). A DC power supply section 10 is inserted between the control section 6 and the AC power supply 9. The DC power supply unit 10 is composed of an auxiliary diode 4, a capacitor 6, a resistor 7, and a voltage regulator diode 3.
The auxiliary diode 4 rectifies the current to flow an AC half-wave current, and the resistor 7 lowers the voltage to provide a low voltage power source.

In addition, the constant voltage diode 3 is connected to an auxiliary diode 4 and a resistor 7.
The capacitor 6 smoothes the AC half-wave voltage limited by the constant voltage diode 3.

The operation of the DC power supply device configured as described above will be explained below.

First, when the input voltage at point A of AC power supply 9 is higher than point 8, current flows from point A through voltage regulator diode 3 and capacitor 6;
Since the voltage is limited to the required voltage, the capacitor 6 is also charged to the same voltage. And the current is resistance 7,
It flows to point B via the auxiliary diode 4, but at this time,
The current is limited by the resistor 7, and the voltage regulator diode 3
This prevents excessive current from flowing through the

Next, when the input voltage at point A of AC power supply 9 is lower than point B, the current is blocked by auxiliary diode 4 and does not flow, and control section 6 operates with the power charged in capacitor 5.

Problems to be Solved by the Invention However, in the conventional configuration described above, since the voltage is dropped by the resistor 7, the power loss Pw at the resistor 7 is determined by the relationship between the input voltage V of the AC power supply 9 and the resistance value R7 of the resistor 7. When expressed as Py,=V/2R7, this becomes the total amount of heat generated in the resistor 7. In particular, when the voltage V is used at 200 V, the power loss Pw increases, the power consumption of the DC power supply unit 10 increases, and electronic components such as microcomputers are heated up by radiant heat and thermally deteriorated. had.

In addition, as another method for stepping down the input voltage V, a transformer can be used, but the cost and weight of the transformer is high, making it difficult to employ it in lightweight home appliances.

The present invention solves the above-mentioned conventional problems, and aims to provide an inexpensive and lightweight DC power supply device that can reduce power loss and heat generation during voltage drop.

Means for Solving the Problems In order to achieve this object, the DC power supply device of the present invention is a DC power supply device inserted between a control unit that controls equipment and an AC power supply, in which current is passed through a voltage drop capacitor. It has a constant voltage diode that rectifies and limits the voltage, an auxiliary diode that rectifies the current, and a voltage smoothing capacitor that is charged with a constant voltage from the constant voltage diode and the auxiliary diode, and the voltage drop The voltage smoothing capacitor is configured to convert the input current of the AC power supply into a phase-delayed current and supply the converted current to the voltage smoothing capacitor.

Effect: With this configuration, the phase of the current flowing through the power supply circuit lags behind the applied voltage, so that the power consumed as loss in the power supply circuit is reduced.

EXAMPLE Below, an example of the present invention will be described based on FIG. Here, parts that are the same as those in the conventional example are given the same numbers and detailed explanations will be omitted.

As shown in the figure, a DC power supply section 1o is inserted between the AC power supply 9 and the control section 6. The DC power supply unit 1° has a noise blocking resistor 1, a voltage drop capacitor 2, and an auxiliary diode 4 (cathode side) connected in series to one end B of the AC power supply 9.
A constant voltage diode 3 (cathode side) is connected to a branch between the voltage drop capacitor 2 and the auxiliary diode 4.

The anode side of the constant voltage diode 3 is connected to the other end A of the AC power supply 9.
Connected to the dots. Further, one end of a voltage smoothing capacitor 5 is connected to the anode side of the auxiliary diode 4, and the other end of the voltage smoothing capacitor 6 is connected to the other end point A of the AC power supply 9, and is controlled from both ends of the voltage smoothing capacitor 50. Part 6
It supplies electricity to.

The operation of the DC power supply device of this embodiment configured as described above will be explained below.

First, when the input voltage at point A of AC power supply 9 is higher than point B, the voltage drop capacitor 2 works to cause a current with a phase delayed with respect to the phase of the power supply voltage to reach constant voltage j, iode 3 and voltage smoothing. After flowing through both the circuits of the secondary capacitor 5 and the auxiliary diode 4, the voltage flows to point B via the voltage drop capacitor 2 and the noise blocking resistor 1.

At this time, the voltage v5 across the voltage smoothing capacitor 5 becomes a voltage (v3-v4) obtained by subtracting the voltage v3 of the constant voltage diode 3 by the forward voltage drop (4) of the auxiliary diode 4. After the voltage smoothing capacitor 5 is charged to the voltage v5, a current flows through the constant voltage diode 3. Note that the capacitance of the voltage drop capacitor 2 is sufficiently smaller than that of the voltage smoothing capacitor 6, and current can continue to flow until the voltage smoothing capacitor 5 is charged to the voltage v5.

Next, when the input voltage at point B of AC power supply 9 is higher than point A, the voltage flows in the opposite direction to the noise blocking resistor 1, voltage drop capacitor 2, and voltage regulator diode 3 in order, but the voltage smoothing capacitor 5 has an auxiliary diode 4, so the above current does not flow.

In this way, power can be supplied to the control unit 6 from the voltage smoothing capacitor 5 charged to the voltage v5.

Note that the noise blocking resistor 1 is configured such that external electrical noise superimposed on the AC power source 9, which is assumed to be in a shipping state, is transmitted to the control unit 6 via the voltage drop capacitor 2 with low AC impedance.
It is inserted to increase the AC impedance in order to prevent malfunction due to intrusion into the AC.

At this time, the power loss P1 in the noise blocking resistor 1 is calculated as follows: where the input voltage of the AC power supply 9 is V, the voltage stepped down by the voltage step-down capacitor 2 is V2, and the resistance value of the noise blocking resistor is R1, P1= (v−v2)2/R1.

Moreover, since the power loss P2 in the voltage step-down capacitor 2 is negligibly small, the power loss P2 in the DC power supply section 1o is
X can be considered as Pl.

Here, the voltage (V-V
In practical terms, 2) can be reduced to the first order of input voltage (2) of the AC power supply 9.

Furthermore, since the resistance value R1 of the noise blocking resistor 1 can be set to approximately the same as the resistance value R7 of the conventional resistor 7, when the loss PX of the DC power supply section 1o is compared with the loss P7 of the conventional example, PX dust ( V-■2) /R1 (v/10)/(R7/10) 1/s, (v/2R7) 175 P 7 , and the power loss Pw can be reduced to 115 of the conventional power loss.

As described above, according to this embodiment, a current that is delayed from the input voltage phase of the AC power source is passed through the voltage step-down capacitor 2, and is passed through the voltage smoothing capacitor 5 to be converted into the required DC voltage. Therefore, power loss in the power supply circuit can be reduced, and the amount of heat generated can be suppressed.

Effects of the Invention The present invention provides a voltage drop capacitor in the DC power supply section,
By passing a current with a phase lag from that of an AC power supply through a voltage smoothing capacitor, even when the AC power supply voltage is high, power loss can be significantly reduced compared to conventional systems, and the power consumption of the DC power supply can be reduced. At the same time, it is possible to realize an excellent DC power supply device that suppresses heat generation, prevents thermal deterioration of electronic components, and can be made cheaper and lighter than the one using a tranne.

[Brief explanation of drawings]

Fig. 1 is a block circuit diagram of a DC power supply according to an embodiment of the present invention, and Fig. 2 is a conventional DC power supply unit.
... Constant voltage diode, 4 ... Auxiliary diode, 6 ... Voltage smoothing capacitor, 6 ...
Control unit, 8...equipment, 9...AC power supply.

Claims (1)

[Claims] In a DC power supply device inserted between a control unit that controls equipment and an AC power source, a voltage drop capacitor, a voltage regulator diode that rectifies current and limits voltage, an auxiliary diode that rectifies current, and the aforementioned It has a voltage smoothing capacitor charged with a constant voltage by a constant voltage diode and the auxiliary diode, and the voltage drop capacitor converts the input current of the AC power supply into a phase-lag current and supplies it to the voltage smoothing capacitor. DC power supply.