JPS6022799Y2 - DC voltage conversion circuit - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a DC voltage conversion circuit.

A conventional DC voltage conversion circuit will be explained with reference to FIG.

The power supply E1 is a negative power supply whose positive pole is grounded, and the power supply E2 is a positive power supply whose negative pole is grounded, and each has two transmission lines RLI.
, RL2.

Two transmission lines RL1. RL2 is connected to the oscillator O3C, and is connected to the power source El through transmission lines RLI and RL2.

Power is supplied to the oscillator from E2.

The AC output of oscillator O3C is connected to the primary winding of transformer T.

The voltage-converted alternating current on the secondary side is converted into direct current by the rectifier circuit RF and supplied to the load.

This conventional method requires a transformer for voltage conversion and input/output insulation, and has the disadvantage of being large in weight and packaging size.

The present invention eliminates such drawbacks and uses a transformer to convert a low-voltage power supply from a power supply that has a series resistance and is grounded on one side, such as in a remote power supply system that supplies power to equipment far away from the power source via a transmission line. The purpose is to obtain it easily and economically.

In other words, the power receiving side receives the power from the power feeding side via a transmission line with a capacitor charging circuit in which a photocoupler is inserted as a current detector, and further maintains continuity between the capacitor and the battery when the discharge current is large. A discharge circuit is constructed by connecting discharge switch circuits having characteristics in series, and the discharge switch circuit is closed after charging is completed under the control of the photocoupler to close the discharge circuit and perform discharge to charge the battery.

Then the capacitor discharges. When this is completed, the discharge switch circuit is turned off, and the above-described charging circuit is again configured.

In this way, it is possible to provide a DC voltage conversion circuit which can supply power from a power source by repeating charging and discharging and which can remotely achieve the above-mentioned purpose.

Hereinafter, the present invention will be explained in detail with reference to the figures.

Fig. 2 shows an example of a circuit according to the present invention, where B is a DC voltage conversion circuit, DC3W is a discharge switch circuit, R3 is a power supply, RL3 is a line resistance of a transmission line, and pcl
, pc2 is a photocoupler for current detection, TR is a transistor, Dl, D2, D3 are diodes, R1,
R2 is a resistor, C is a capacitor, BAT is a battery, and SW is a switch.

The power source E3 has a positive electrode grounded and a negative electrode connected to the transmission line.

In the DC voltage conversion circuit B, the cathode side of the photocoupler PCI is connected to the transmission path, and the anode side is connected to the emitter of the transistor TR of the discharge switch circuit DC3W, the emitter of the photocoupler PC1, the anode of the photocoupler PC2, and the resistor R1. .

Note that the resistor R1 may be replaced with a diode.

In the discharge switch circuit DC3W, the collector of the transistor TR is grounded, the emitter of the photocoupler PC2 is connected to the base, and the collector of the photocoupler PC2 is grounded.

Further, the base of the transistor TR is connected to the cathode of a diode D3, and the anode of the diode D3 is connected to the collector of a photocoupler PC1 and one end of a resistor R2.

The cathode of the photocoupler PC2 is connected to the other end of the resistor R1 and one end of the capacitor C.

The other end of the capacitor C is connected to the cathode of the diode D1 and the anode of the diode D2.
The anode of is grounded.

Furthermore, the anode of the diode D2 is connected to the positive electrode of the battery BAT, which is a load, and the negative electrode of the battery BAT is grounded.

Here, when the switch SW is turned on, the power source E on the power supply side
The current of 3 is as follows: earth - diode D1 - capacitor C - resistor R1 - photocoupler pc1 (anode - cathode) - transmission line RL3
- Switch SW - Power supply E3, and a charging circuit for capacitor C is configured.

The current flowing through the photocoupler pc1 (anode-cathode) turns on the photocoupler PCI (collector emitter).

Since no current flows through the photocoupler PC2, the photocoupler pc2 (collector emitter) is turned off, so that the base 'WIFE' of the transistor TR does not flow and the transistor TR is turned off.

In this state, the capacitor C is charged by the current from the power source E3.

As charging approaches the end, the current decreases, turning off the photocoupler PCI (collector emitter).

Then, a current flows to the base of the transistor TR via the ground, the resistor R2, and the diode D3, and the transistor is turned on.

When transistor TR is turned on, a current due to the charge charged in capacitor C flows through the following circuits: capacitor C - diode D2 - battery BAT - transistor TR (collector emitter) - photocoupler p
A charging circuit is created that charges the battery BAT through the path c2 (anode-cathode)-capacitor C.

Also, by turning on the transistor TR, the photocoupler pc1 (anode-cathode) is connected to the earth, the transistor TR (collector emitter), the photocoupler pc1 (anode-cathode), and the transmission line RL3.
A current flows through the path of - switch SW - power supply E3 and turns on, but due to the discharge current of capacitor C, photocoupler pc2 (collector emitter)
is turned on, so that the base current of transistor (2) is secured, and as long as this current is large, transistor TR continues to operate.

When the voltage of capacitor C decreases and approaches the voltage of battery BAT, photocoupler pc2 (anode-cathode)
The current flowing through the photocoupler PC2 (anode-cathode) is turned off.

At this time, since current is flowing through the photocoupler pc1 (anode-cathode) through the above path, the photocoupler pc1
1 (collector emitter) is on, transistor TR is off.

Here, the charging circuit of the capacitor C by the power source E3 is closed again, and charging is performed.

In this way, capacitor C is repeatedly charged and discharged, and battery BAT is charged.

As explained above, according to the present invention, a low voltage power source can be obtained from a power source having a series resistance (line resistance, etc.) using a simple and economical circuit without using a transformer.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a conventional DC voltage conversion circuit, and FIG. 2 shows a DC voltage conversion circuit according to the present invention. A, B...DC voltage conversion circuit, DC3W...
...discharge switch circuit, El, E2. E3...
...Power supply, RLl, RL2. RL3... Transmission line resistance, OSC... Oscillator, T...
Transformer, RF... Rectifier circuit, L... Load, R1, R2... Resistance, DI, D2. D
3...Diode, C...Capacitor, TR...Transistor, BAT...
Battery, PCL, PC2...Photocoupler,
SW...Switch.

Claims (1)

[Claims for Utility Model Registration] In a DC voltage conversion circuit that obtains a low voltage from a power source having a series resistance (line resistance, etc.) without using a transformer, the anodes of the first and second photocouplers PC1 and PC2 are connected to each other. The emitter of the transistor TR is connected to the anode and emitter of the first photocoupler and the anode of the second 7-photocoupler, and the collector of the first photocoupler and the second photocoupler are connected to the base via a diode D3. The emitter of the photocoupler is connected, and the collector is connected to the above diode D3 and the resistor R connected to the collector of the first photocoupler.
2 and the collector of the second photocoupler are connected, and this collector is connected to a power supply. Furthermore, a resistor R1 is connected in parallel between the anode and cathode of the second photocoupler, and the cathode of the first photocoupler is The anode is connected to the power source via a transmission path, and the anode is connected to the power source through a diode D1 whose polarity is set in a direction to conduct the charging current to the resistor R1 and the capacitor C. Furthermore, the diode D1 is connected to the diode D1. A diode D2 which is in the opposite direction and forms a series circuit with the battery BAT is connected in parallel, and the series circuit is connected to the collector of the transistor m to transmit the discharge current of the capacitor C, and the capacitor C is repeatedly charged and discharged. A DC voltage conversion circuit characterized by obtaining low voltage by