JPH09103071A - Time-division parallel operation type step-up chopper circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To pull up output power to double without increasing the peak current of a switching element, and to reduce a ripple current by conducting flip-flop operation by the signal output of Q and the signal output of Q' and preventing overlapping on a time series. SOLUTION: The block of two pairs of choke coils 3, 4, switching elements 5, 6 and rectifier diodes 7, 8 is connected to one input electrolytic capacitor 1, and the output side is used as one output electrolytic capacitor 9. Parts having the two signal outputs of Q and Q' as flip-flop outputs in a step-up control circuit 2 are connected to the switching elements 6, 6 respectively, and recycling, in which the switching element 6 on the Q' side is turned off when the switching element 5 on the Q side is turned on and the switching element 5 on the Q side is turned off when the switching 6 on the Q' side is tuned on, is continued. Accordingly, output power is pulled up to double, and a ripple current can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention divides a current flowing when a switch element is ON in time series when operating a step-up chopper circuit in parallel, so that the current flows to a switching element when the output is expanded in an isolated operation. The improvement of the boost chopper circuit that suppresses the heat loss by suppressing the maximum value of the peak current, and also suppresses the increase of the ripple current of the input electrolytic capacitor and the output electrolytic capacitor to achieve a small size and high output as a whole. Is.

[0002]

2. Description of the Related Art In order to boost a required DC voltage from a DC voltage lower than that, a boost chopper circuit is used in an independent operation. FIG. 2 shows an example of a conventional step-up chopper circuit. The principle of this circuit is that magnetic energy is accumulated in the choke coil 12 during the ON time of the switching element 14 and this energy is released during the next OFF time to lower the input. The output voltage required is taken out from the voltage, but when the output voltage is fixed from the same input voltage and the output voltage that can be taken out is doubled, the input and output electrolytic capacitors 1 and 9 and the choke coil are used. 12, the switching element 14, and the rectifying diode 13 are required twice, so that the volume of the power source becomes large. In the figure, reference numeral 11 is a boost control circuit.

Therefore, in order to obtain a high output power in a smaller volume, it is necessary to suppress the ripple current of the input / output electrolytic capacitor, suppress the peak current flowing in the switching element, and suppress the size of the heat radiation fin. There is.

[0004]

In the single operation of the boost chopper circuit, the ripple current of the input / output electrolytic capacitor is proportional to the peak current flowing when the switching element is ON, and is influenced by the ratio of ON time and OFF time. . Therefore, if the output is expanded in the same circuit, the ripple current of the electrolytic capacitor may increase and the life may be shortened. Therefore, it is necessary to increase the capacitance and voltage to increase the ripple current withstand capability.

Further, in the isolated operation of the step-up chopper circuit, the peak current flowing when the switching element is ON flows in proportion to the input current, and if the output power is doubled, the input current is doubled. Since the peak current also doubles, the power loss of the switching element is I ²
It increases four times with R. Therefore, it is necessary to double the output power and quadruple the number of elements in parallel in order not to increase the loss.

[0006]

Two sets of choke coils, switching elements, and rectifying diode blocks are connected to one input electrolytic capacitor, and one output electrolytic capacitor is provided on the output side. Next, a step-up control circuit having two signal outputs Q and Q ', which are flip-flop outputs, is connected to the switching elements respectively, and when the switching element on the Q side is ON, switching on the Q'side is performed. Turn off the element, then switch the switching element on the Q'side to O
The output power can be doubled without increasing the peak current of the switching element by continuing the cycle of turning off the switching element on the Q side during N, and the discharge time ratio from the input electrolytic capacitor can be increased. Since it becomes longer, the ripple current can be reduced.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Two sets of choke coils, a switching element, a rectifying diode, and a boost control circuit having two signal outputs which are flip-flop outputs are used.
Two signal outputs are respectively connected to two sets of switching elements, and when one switching element is ON, the other switching element is turned OFF, and when the other switching element is ON, one By operating the two sets in parallel so as to continue the cycle of turning off the switching element, the output power can be doubled without increasing the peak current of the switching element, and the ripple current can be reduced.

[0008]

1 is a diagram showing an embodiment of a boost chopper circuit according to the present invention, in which 1 is an input electrolytic capacitor connected in parallel on the input side, and 2 is a boost control circuit having two outputs Q and Q '. is there. 3 is a Q side choke coil, 4 is a Q'side choke coil, 5 is a Q side switching element, 6 is a Q'side switching element, 7 is a Q side rectifying diode, and 8 is a Q '.
Side rectifying diodes, 3 and 4, 5 and 6, 7 and 8 are
The peak current values are balanced by combining those with the same electrical rating and electrical performance.

Reference numeral 9 is an output electrolytic capacitor connected in parallel on the output side, and 10 is an output voltage dividing resistor, which is required from the input voltage obtained by feeding back the voltage obtained here to the boost control circuit 2. The value of the resistor 10 is set so that the output voltage to be obtained is obtained.

The signal output of Q and the signal output of Q'perform a flip-flop operation, and two sets of boost chopper circuits are operated in parallel so that they do not overlap in time series.

[0011]

As described above, according to the present invention, when the step-up chopper circuits are operated in parallel, the peak current flowing through the switching element is divided by dividing the current flowing when the switching element is ON in time series. Of the input electrolytic capacitor and the output electrolytic capacitor are prevented from increasing, and the overall size and size of the output can be increased.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a time-division parallel operation type boost chopper circuit of the present invention.

FIG. 2 is a diagram showing an example of a conventional boost chopper circuit.

[Explanation of symbols]

 1 Input Electrolytic Capacitor 2 Boost Control Circuit 3 Q-Side Choke Coil 4 Q'Side Choke Coil 5 Q-Side Switching Element 6 Q'Side Switching Element 7 Q-Side Rectifier Diode 8 Q'Side Rectifier Diode 9 Output Electrolytic Capacitor 10 Output Voltage Divider Resistor

Claims (1)

[Claims] 1. An input electrolytic capacitor, a boost control circuit having two outputs Q and Q ', a Q side choke coil, a Q'side choke coil, a Q side switching element, and a Q'side switching element. Q side rectifying diode, Q'side rectifying diode, output electrolytic capacitor,
A time-division parallel operation type step-up chopper circuit comprising an output voltage dividing resistor, wherein the Q signal output and the Q'signal output perform a flip-flop operation and do not overlap in time series.