JPS5858907B2 - power supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power supply device having a DC-DC converter with high conversion efficiency.

DC power supply voltage ■1 is the DC voltage required for wireless equipment, etc.■
2, a switching type DC-DC converter is used as shown in FIG.

Such a conventional DC-DC converter has a conversion efficiency of about 80 factors.

In addition, unmanned wireless relay stations that use solar cells as a floating charging power source for secondary batteries have been realized.Solar cells have the advantage of requiring almost no maintenance compared to engine generators, etc. Since these devices are very expensive, efforts are being made to reduce the power consumption of wireless relay devices, thereby reducing the capacity of secondary batteries and solar cells.

As a power source for such a wireless relay device, a conventional switching type DC-DC converter is still not efficient enough.

The present invention aims to provide a power supply device with improved DC voltage conversion efficiency, and also uses a microwave FET as a load.
The object of the present invention is to provide a power supply device using a (field effect transistor) amplifier.

Examples will be described in detail below.

FIG. 2 is a block diagram of an embodiment of the present invention, in which 1 is a solar cell, 2 is a backflow blocking diode, 3 is a secondary battery, and 4 is a block diagram of an embodiment of the present invention.
is a power switch, 5 is an isolated switching DC-DC converter, a, b are input terminals, c, d are output terminals, e is a control terminal, 6 is a DC-DC converter, 1 is a voltage detection circuit, 8 is a protection circuit , 9 is a wireless device having a microwave FET amplifier, and R1 and R2 are voltage dividing resistors.

The isolated switching DC-DC converter 5 has an output terminal d and an input terminal a connected, and applies the voltage between the output terminal C and the input terminal S to the wireless device 9 as an output voltage 2. The voltage (2) is divided by resistors R1 and R2 to obtain a control voltage, and the control voltage is applied to the control terminal (e) to stabilize the output voltage (2).

Voltage ■1 of the secondary battery 3 is applied to input terminals a and b, and ■
, <v2, but the voltage converted by the isolated switching DC-DC converter 5 is (V2 Vl), and the voltage V is added to the converted output voltage to obtain the output voltage. v2.

Therefore, the total conversion efficiency η is Letting its own conversion efficiency be η′, DC converter 5 becomes.

For example, if V=6V, V2=12V, and η780, then η-90%.

That is, the conversion efficiency η is greater than the conversion efficiency η′ of the conventional DC-DC converter.

The secondary battery 3 is connected to a reverse current blocking diode 2 by the solar cell 1.
Floating charged via power switch 4
By turning on, the voltage v of the secondary battery 3 increases as described above.
1 is converted into a voltage v2 and supplied to the wireless device 9.

If this voltage (2) is taken as the drain voltage of the microwave FET amplifier, it is necessary to apply the gate voltage before the drain voltage is established.

Therefore, the output voltage of the DC-DC converter 6 for generating the gate voltage is detected by the voltage detection circuit 7, and the contact of the protection circuit 8 is turned off.

That is, when the contact of the protection circuit 8 is on, the voltage 1 applied to the input terminals a and b is applied to the control terminal e of the isolated switching DC-DC converter 5 as a control voltage, so that the isolated switching DC-DC The output voltage (2) of the DC converter 5 is controlled to be low.

When the output voltage of the DC-DC converter 6 is established, the contact of the protection circuit 8 is turned off by the voltage detection circuit 7, and the output voltage 2 is divided by the resistors R1 and R2 to become the control voltage. The switching DC-DC converter 5 operates normally and can apply the drain voltage of the microwave FET amplifier.

FIG. 3 shows the circuit configuration of an example of an isolated switching DC-DC converter, in which 51 is a resistor, 52 is a Zener diode, 53 is a comparator, 54 is a pulse generation circuit,
55, 56 are switching transistors, 57 is a capacitor, 58 is a transformer, 59.60 is a diode, 61
is an inductance, and 62 is a capacitor.

The voltage of the secondary battery 3 applied to the input terminals a and b is divided by the resistor 51 and the Zener diode 52 to become a constant reference voltage, and the reference voltage and the control voltage applied to the control terminal e by the comparator 53 are divided. The comparison output is applied to the pulse generation circuit 54.

The pulse generation circuit 54 includes a switching transistor 55.
It generates pulses to be applied to the base of 56, and is connected to the reference voltage and control voltage. [The pulse width, pulse period, pulse amplitude, etc. are controlled so that the pressures become equal, and the switching transistors 55 and 56 are alternately turned on and off.

As a result, an AC voltage is induced in the secondary winding of the transformer 58, which is rectified by the diode 59, 60, smoothed by a smoothing circuit including an inductance 61 and a capacitor 62, and a DC voltage is output from output terminals c and d. .

The output terminal d is connected to the input terminal a as described above, and the voltage between the output terminal C and the input terminal A is applied to the wireless device 9 as the output voltage v2.

Note that the DC-DC converter 6 that generates the gate voltage is also an isolated switching DC-D converter that generates the drain voltage.
The configuration can be similar to that of the C converter 5.

In addition, the contacts of the protection circuit 8 are isolated switching DC-DC
It can also be provided on the input terminal side of the converter 5.

Moreover, the wireless device 9 as a load can also be a load of any other configuration.

As explained above, the present invention provides isolated switching D
Since the sum of the output voltage of the C-DC converter 5 and the input voltage applied to input terminals a and b is applied to the load, the overall conversion efficiency is higher than that of the conventional example, and the capacity is small. Even when the secondary battery 3 is used as a power source, there is an advantage that sufficient power can be converted to a predetermined voltage and supplied to the load.

Therefore, it is very effective in practical use as a power supply device for operating a wireless relay device using the secondary battery 3 which is floatingly charged by the solar cell 1.

In addition, a detection means such as a voltage detection circuit 7 for detecting the gate bias voltage of the FET amplifier of the load is provided, and before the gate bias voltage reaches a normal value, the isolated switching DC-D
When the input voltage V1 is applied to the control terminal e of the C converter 5 and a normal value is detected, a protection circuit 8 is provided that controls switching so that the input voltage 1 is not applied, so that the gate bias voltage After becomes a normal value, the drain voltage is applied due to the normal operation of the isolated switching DC-DC converter 5.

Therefore, there is an advantage that normal operation of the FET amplifier can be guaranteed.

Since a voltage proportional to the output voltage (2) is applied to the control terminal e, the drain voltage of the FET amplifier can be stabilized.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a power supply device consisting of a conventional DC-DC converter, Figure 2 is a block diagram of an embodiment of the present invention, and Figure 3 is a circuit diagram of the main parts of an isolated switching DC-DC converter. be. 1 is a solar cell, 2 is a reverse current blocking diode, 3 is a secondary battery, 4 is a power switch, and 5 is an isolated switching DC-
6 is a DC-DC converter, 7 is a voltage detection circuit, 8 is a protection circuit, and 9 is a wireless device.

Claims (1)

[Claims] 1 Connect one input terminal and one output terminal of an isolated switching DC-DC converter, and connect the other input terminal and the other output terminal to the isolated switching DC-DC converter.
The isolated switching DC-DC converter is connected so that the sum of the output voltage of the C converter and the input voltage applied to the input terminal is applied as the drain voltage of the FET amplifier of the load, and a voltage proportional to the voltage applied to the load is applied to the isolated switching DC-DC converter. means for detecting the gate bias voltage of the FET amplifier;
Before detecting that the gate bias voltage of the T amplifier has reached a normal value, apply the input voltage to the control terminal, and when it is detected that the gate bias voltage of the T amplifier has reached a normal value, apply the input voltage to the side terminal. A power supply device characterized in that it is equipped with a protection circuit that performs switching control to prevent overloading.