JPS6070967A - Dc power source circuit - Google Patents

Abstract

PURPOSE:To prevent the damage of a switch and to enhance the efficiency by providing a main coil of a driven reactor between the anode side of a diode for emitting energy and the switch, and feeding back the energy stored in the coil to an input power source. CONSTITUTION:A main coil 10b of a driven reactor is inserted between the anode side of a diode 4 for emitting energy and a switch 3, thereby suppressing di/dt when the switch 3 is closed. The energy stored in the main coil 10b of the driven reactor is fed back to an input power source 1 through another coil 10c of the driven coil during the ON period of the switch 3.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a DC power supply circuit for stabilizing DC voltage supplied by human power or converting it into another DC voltage and supplying the converted DC voltage to a load side. It is related to.

[Prior art]

Figures 1 and 2 show a booster type circuit that boosts the input DC voltage, which is a type of conventional power supply circuit.
is an input DC power supply, 2 is a load, 3 to 6 are components forming the booster circuit, 3 is a switch for storing energy in the reactor 6, and 4 is the energy stored in the reactor 6 when the switch 3 is turned off. This is a diode for discharging the voltage to the capacitor 5 and the load 2. Also,
The circuit shown in FIG. 2 is an improved version of the circuit shown in FIG. A secondary coil closely coupled to the primary coil 6a of the storage reactor 6, 7.8 a diode, 9 a capacitor for energy bypass when the switch 3 is off, 10
is a reactor for expanding the discharge time constant of the capacitor 9.

Also i3. i4 is the current flowing through the switch 3 and diode 4, 3 is the voltage across the switch 3, 1
9 is a current that is charged and discharged into the capacitor 9.

Next, the operation will be explained. First, in FIG. F, when switch 3 is turned on, current flows through reactor 6 and energy is stored. At this time, load 2 has capacitor 5.
More energy is being supplied to the diode 4, and a reverse voltage is applied to the diode 4, turning it off.

Next, when switch 3 is turned off, the energy stored in reactor 6 is released to load 2 and capacitor 5 through diode 4. The output voltage is when switch 3 is on/off.
This type of circuit, which is determined by the off-ratio, is the most common booster circuit, and the operating waveforms of each part are shown by broken lines in FIG.

Next, the operation of the circuit shown in FIG. 2, which is obtained by adding a circuit for reducing the loss when the switch 3 is turned off to the circuit shown in FIG. 1, will be described. Younger brother, if we look at the on period of switch 3 from time tO to t1 in Figure -4, the primary coil 6 of reactor 6
An input voltage is applied to a through the switch 3, and a back electromotive force of 0 is generated on the side marked with . Therefore, the secondary coil 6b
A voltage of 10 on the sign side is induced, and the charge in the capacitor 9 is discharged to the load 2 with a time constant determined by the inductance of the reactor 10 and the capacitance of the capacitor 9, and prepares for energy absorption when the switch 3 is turned off.

Next, when the switch 3 is turned off at time t1, the current flowing through the primary coil 6a of the reactor 6 decreases while flowing through the diode 7 and capacitor 9 connected in parallel with the switch 3. At this time, the polarity of the voltage generated in the secondary coil 6b of the reactor 6 is -. It works as expected. As a result, the voltage V3 across the switch 3 when the switch 3 is off is
dv/dt becomes extremely small, and the surge S caused by leakage inductance as shown in Fig. 4 can be eliminated.
The switching loss becomes extremely small, and the load curve when the switch 3 is off also becomes like a capacitor load. At time t2, the capacitor 9 completes charging, and the energy stored in the reactor 6 is released through the energy release diode 4.

In the case where the operation mode is generally called capacitor input mode (a mode in which the energy stored in the reactor is completely charged and discharged in each cycle, and there is a period in which no current flows through the reactor), the second
The circuit shown in the figure operates without problems, but in the case of the so-called choke input mode (mode in which the reactor current is continuous), when the switch 3 is turned on, during the reverse recovery time of the energy discharging diode 4, the dashed line in FIG. As a result, d i /d t of the switch 3 becomes large, and the loss when the switch 3 is turned on becomes large, resulting in damage to the switch 3.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and by inserting the main coil of a secondary reactor between the anode side of the energy emitting diode and the switch, when the switch is turned on, By suppressing di/dt and feeding back the energy accumulated in the main coil of the slave reactor during the switch-on period to the input power supply through another coil of the slave reactor, even in choke input mode operation, The purpose of the present invention is to provide a DC power supply circuit that can reduce loss and prevent damage to switches.

[Embodiments of the invention]

An embodiment of this invention will be described below. In FIG. 3, 10b and 10c are a secondary coil and a tertiary coil respectively coupled to the primary coil 10a of the time constant expansion reactor 10, and the secondary coil lOb is connected to the anode side of the energy emitting diode 4. It is connected in series between the switches 3, and the tertiary coil 1'Oc is connected in parallel to the input power source 1, and both coils 10b and IOC are connected so that their polarities are in the directions indicated by the marks. 11
is an energy feedback diode for returning the energy accumulated in the secondary coil 1°b when the switch 3 is on to the input power source 1 through the tertiary coil 10c when the switch 3 is off.

Next, the effects will be explained.

First, during the period when the switch 3 is on (time point 10-11), current flows through the switch 3 and energy is stored in the reactors 6a and 10b. At this time, Akudoru 10
Since a voltage of 10 is induced on the side marked with c, the diode 11 is off.

Next, when the switch 3 is turned off, the current in the reactors 6a and 10b flows through the diode 7 and the capacitor 9, charging the capacitor 9, and the side marked with - becomes - in the reactor 10c, as in the case of FIG. , the diode 11 is turned on, and the energy stored in the reactor 10b is fed back to the input power source 1. And the voltage of switch 3 is (output voltage) + (voltage drop of diode 4) + (
The voltage across the reactor 10b rises to 5.0, and the energy in the reactor 6a is transferred to the capacitor 5. Discharged to load 2. Here, in order to suppress the voltage applied to switch 3,
Normally, it is better to increase the ratio of reactors 10c and 10b.

Next, when switch 3 is turned on, diode 4
The reverse current ir from the capacitor 5 due to the reverse recovery time is suppressed by the reactor 10b, and the discharge time constant of the capacitor 9 due to the capacitor 9 and the reactor 10a is also sufficiently large, so as shown in FIG.
d i /d t of the current i3 when the switch 3 is on can be made sufficiently small.

Therefore, according to the circuit of this embodiment, even in the choke input mode where current flows continuously through the reactor, it is possible to reduce the loss when the switch 3 is turned on and off, and the switch 3 can be prevented from being damaged. I can't even close it.

In the above embodiment, a separate coil of the time constant expansion reactor was used as the reactor for suppressing the reverse current of the diode, but this may be configured with a completely different core.

〔Effect of the invention〕

As described above, according to the present invention, in a DC power supply circuit in which the current flowing through the main reactor is turned on and off by a switch, and the input DC voltage is stabilized and supplied to the load, a diode and a capacitor are connected in parallel to the switch. A current bypass circuit consisting of a series circuit with the secondary coil of the main reactor is provided, and the main coil of the secondary reactor is inserted between the above switch and the anode side of the energy emitting diode, so that when the switch is turned on, the main coil of the secondary reactor is By suppressing the flowing d i / d t and using a separate coil of the secondary reactor to return the energy accumulated in the main coil of the secondary reactor to the power supply, both on loss and off loss during switching are minimized. It can be made smaller and the stress on the parts can be reduced.
Improves reliability and reduces loss at the same time.

This has the effect of providing a DC power supply circuit with low heat generation.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing a general booster circuit, Fig. 2 is a circuit diagram of a booster circuit equipped with a circuit for reducing loss at switch-off, and Fig. 3 is a direct current circuit diagram according to an embodiment of the present invention. A circuit diagram showing the power supply circuit, and FIG. 4 is an explanatory diagram of its operation. 1... Input DC power supply, 2... Load, 3... Switch, 4... Energy release diode, 6... Main reactor, 6a... Primary coil, 6b... Secondary Coil, 7...Diode, 8...Diode (discharge circuit), 9...Capacitor, 10...Reactor (
discharge circuit), 10b...secondary coil (main coil of the slave reactor), 10c...tertiary coil (another coil of the slave reactor). In the drawings, the same reference numerals indicate the same or equivalent parts. Agent Masuo Oiwa 0 Figure 1 JP-A-Sho GO-70967 (4) Figure 4

Claims (1)

[Claims] (11) A DC power supply circuit that stabilizes the human-powered DC voltage and supplies it to the load, with a switch that cuts off the current flowing to the primary coil of the main reactor and turns off the circuit, and a switch between the primary coil of the main reactor and the load. an energy release diode connected in series for releasing the energy accumulated in the primary coil to the load side when the switch is turned off;
A series circuit including a diode, a capacitor, and a secondary coil connected to the primary coil of the main reactor in a direction to lower the potential of the capacitor when the switch is turned off, which is connected in parallel to the switch, and the switch. a discharge circuit that discharges the energy of the capacitor during the on-period of the switch; a main coil of a secondary reactor connected between the anode side of the energy release diode and the switch;
A DC power supply circuit comprising: a separate coil of the slave reactor which is coupled to the main coil of the slave reactor and returns energy accumulated in the main coil of the slave reactor to the power source when the switch is turned off.