JP6963252B2 - Chopper type DC / DC converter and space chopper type DC / DC converter - Google Patents

Description

The present invention relates to a DC / DC converter (DC voltage converter), and more particularly to a chopper type DC / DC converter suitable for POL (Point of Load) applications and suitable for space electronic devices.

A general-purpose chopper-type DC / DC converter for vehicle mounting and the like is disclosed in, for example, Japanese Patent Application Laid-Open No. 2006-340582 "DC / DC converter and power supply device for vehicles" of Patent Document 1. In FIG. 1 of Patent Document 1, the MOSFETs Q1 to Q4 in the first input system (11) and the MOSFET Q5 in the second input system (12) are switched by a control device (21) common to both input systems. The first input system (11) generates an isolated output, the second input system (12) generates a non-insulated output, and either the insulated output or the non-insulated output is selected to select the output unit (10). ) Chopper type DC / DC converter that supplies DC power to the outside is shown. The control device (21) is a switching control means for turning on / off switching elements such as MOSFETs and transistors, and is widely known as a DC / DC converter control IC (integrated circuit). This control device (21) controls ON / OFF of the switching element by a PWM (Pulse Width Modulation) method or a PFM (Pulse Frequency Modulation). In the present application, a switching control means for controlling ON / OFF of a switching element is referred to as a DC / DC converter control IC (or "control IC" for short).

Such a chopper-type DC / DC converter is also put into practical use as a space POL DC / DC converter. Electronic components mounted on space electronic devices such as rockets and satellites have the performance to withstand radiation, vacuum environment, low and high temperature environments, and vibration environment at the time of rocket launch in order to perform sound operation in outer space. Must have. For this reason, it is difficult to use general-purpose electronic components that are generally used, and unique electronic components that have been certified to be resistant in the space environment after undergoing advanced environmental tests are used.

In space DC / DC converters, there is a great demand for isolated DC / DC converters that reduce the effects of failures that occur in other circuits and that can easily block noise mixed in from other circuits. On the other hand, high-performance semiconductors such as microcontrollers and ASICs require DC / DC converters that operate at low voltage and large current, so they are located near the semiconductor so that they can meet the demand for low voltage and large current. The POL (Point of Load) non-isolated DC / DC converter to be arranged is currently used in space electronic devices.

Japanese Unexamined Patent Publication No. 2006-340582

As mentioned above, space electronic components have been put into practical use after undergoing extremely advanced environmental resistance tests. Non-insulated space POL DC / DC converters have already been certified and put into practical use as space electronic components. Therefore, it is desired to realize an insulated DC / DC converter by utilizing the design assets and parts (control IC, etc.) of the current non-insulated space POL DC / DC converter. FIG. 2 is a circuit diagram showing a DC / DC converter capable of isolated output, which was devised by utilizing a current space POL DC / DC converter. In FIG. 2, the non-isolated space POL DC / DC converter is shown as the POL application circuit A, and the circuit that enables the insulation output by adding to the POL application circuit A is shown as the additional circuit B, each surrounded by a broken line. There is.

In the POL application circuit A, 1 is a control IC (PWM-IC), Q1 and Q2 are MOSFETs, T1 is a transformer, n1 is the primary winding of the transformer T1 (number of turns: n ₁ ), and n2 is the secondary winding of the transformer T1. (Number of turns: n ₂ ). Further, R1 and R2 are, divide the voltage _{V 1} of the non-isolated output min, feeds back the output voltages _{V 1} resistor to the control IC (PWM-IC) 1. The control IC (PWM-IC) 1 controls the pulse width of the pulse signal that turns ON / OFF the MOSFETs Q1 and Q2 by feeding back the _{output voltage V 1, that is, controls the duty ratio of the pulse signal and outputs the output voltage.} The V ₁ and the output voltage V ₂ are stabilized to predetermined values, respectively. The control IC (PWM-IC) is also referred to as a non-insulated space PWM-IC.

More specifically, the control IC (PWM-IC) 1 controls MOSFET Q1 ON / OFF with a pulse of a predetermined frequency, _{and the input voltage input to the input terminal VIN} is set to the primary winding of the transformer T1 according to the width of the pulse. Send to line n1. The transformer T1 acts as a reactor in the DC / DC converter. During the period when the MOSFET Q1 is OFF, the magnetic energy stored in the transformer T1 generates a counter electromotive force in the primary winding n1 in the same direction as the ON period of the MOSFET Q1. In the path of the parallel circuit of the diode D5, the primary winding n1, the resistors R1 and R2, and the parallel circuit of the capacitor C2, a current flows in the same direction as the ON period of the MOSFET Q1. If a load is connected between the output terminal + 3.3V _{OUT and RTN, a load current I 1} flows in addition to the parallel circuit of the resistors R1 and R2 and the capacitor C2. In the additional circuit B, the diode D4 and the capacitor C3 form a rectifier circuit.

DC / DC converter of FIG. 2 has a + _{3.3V OUT} terminal of the output voltage _{V 1,} and a _{+ 5V OUT} terminal of the output voltage _{V 2.} Since the + 3.3V _OUT terminal is electrically connected to the input terminal V _IN , the output voltage V ₁ is a non-isolated output. On the other hand, since the + 5V _OUT terminal is electrically cut off from the _{input terminal VIN} by the transformer T1 _{, the output voltage V 2} is an isolated output. That is, the DC / DC converter of FIG. 2 has both a non-insulated output and an insulated output.

In the case of the circuit system of FIG. 2, the exciting current flowing through the transformer T1 plays a role of transmitting electric power to the isolated output. Therefore, in order to extract power from the insulated output, it is necessary to pass a current through the non-insulated output as well. Looking at the ratio of the power that can be taken out as the non-insulated output and the insulated output, respectively, assuming that the currents output from the non-insulated output and the insulated output are I ₁ and I _{2 , the power W 1} (= V ₁ I) of the non-insulated output. _{The ratio (power ratio) between 1} ) and the isolated output power W ₂ (= V ₂ I ₂ ) is empirically about 1: 3, that is, if the non-insulated output power of _{the voltage V 1 is 3, the voltage V} The isolated output power of _{2 is approximately 1.} For example, if the total output power is 8 W (watt), the non-insulated output power is 6 W and the insulated output power is about 2 W. From the ratio of the electric power that can be taken out, it seems that the circuit method of FIG. 2 can be used in the case of a device that uses both an insulated output and a non-insulated output. However, even if only the insulated output is to be used, a dummy current needs to be passed through the non-insulated output as well, so that the circuit method of FIG. 2 is not desirable in terms of power efficiency. When the circuit method of FIG. 2 is adopted, the design of the transformer T1 is simply a turn ratio, so that the non-insulated output voltage V ₂ and the insulated output voltage V ₁ have a relationship as shown in the equation (1). ..
V ₂ = (n ₂ / n ₁ ) V ₁ (1)

Therefore, in order to solve such a problem, the present invention utilizes a non-isolated POL DC / DC converter for space, which has already been certified for space use and is currently in use, and requires a great deal of time and cost. It is an object of the present invention to provide a chopper-type DC / DC converter capable of insulating output having excellent power efficiency and which can be used for space without requiring such an environmental resistance test.

In order to solve the above-mentioned problems, the chopper type DC / DC converter and the space chopper type DC / DC converter according to the present invention mainly adopt the following characteristic configurations.

(1) The chopper type DC / DC converter according to the present invention is
One terminal of the DC power supply is connected to one terminal of the first capacitor, and the other terminal of the DC power supply is connected to the first capacitor via a series circuit including a first switch element and a primary winding. Connect to the other terminal, connect a rectifying element between one terminal of the first capacitor and the primary winding side terminal of the first switch element, and connect the voltage across the first capacitor. A control IC for controlling the voltage to be constant by controlling the switching of the first switch element based on the information is provided, a secondary winding electromagnetically coupled to the primary winding is provided, and the primary winding and the primary winding are provided. The secondary winding constitutes a transformer, a first diode for rectifying and smoothing the voltage generated in the secondary winding and a second capacitor are connected, and the first switch element is alternately controlled to be ON or OFF. A chopper-type DC / DC converter in which the first diode is alternately turned OFF or ON, and the first load device is connected in parallel with the second capacitor.
A second diode is inserted in series with the first capacitor side of the primary winding, and a second diode is inserted between the primary winding side terminal of the second diode and one terminal of the first capacitor. The control IC is characterized in that the second switch element is connected and the second switch element is switched in synchronization with the first switch element.
(2) The chopper-type DC / DC converter for space according to the present invention is the chopper-type DC / DC converter according to (1) above.
An insulated output can be obtained by using a non-insulated space PWM-IC applied to a space POL DC / DC converter as the control IC and using the reactor in the space POL DC / DC converter as the transformer. It is a feature.

According to the present invention, the non-isolated POL DC / DC converter for space, which has already been certified for space use, is utilized without requiring a great deal of time and costly environmental resistance test. , A chopper-type DC / DC converter capable of insulating output with excellent power efficiency, which can be used for space, can be provided.

It is a circuit diagram which shows the chopper type DC / DC converter which is one Embodiment of this invention. It is a circuit diagram which shows the chopper type DC / DC converter which is configured by converting the reactor of the current non-isolated chopper type DC / DC converter for space into a transformer, and can obtain the isolated output. It is a circuit diagram of the chopper type DC / DC converter which summarized the main points of this invention. It is a circuit diagram which shows the main points of the chopper type DC / DC converter which is configured by converting the reactor of the current non-isolated chopper type DC / DC converter into a transformer. FIG. 5 is a circuit diagram showing an example in which a transformer in FIG. 1 is converted into a reactor to form a non-insulated buck-boost chopper type DC / DC converter.

Hereinafter, preferred embodiments of the chopper-type DC / DC converter according to the present invention will be described with reference to the accompanying drawings. The space chopper type DC / DC converter according to the present invention will be described as an example of the chopper type DC / DC converter in the following description. It goes without saying that the drawing reference reference numerals attached to the following drawings are added to each element for convenience as an example for assisting understanding, and the present invention is not intended to be limited to the illustrated embodiment. stomach.

FIG. 1 is a circuit diagram showing a chopper type DC / DC converter according to an embodiment of the present invention. In the chopper type DC / DC converter of FIG. 1, the control IC represented by reference numeral 1 will be described below as a PWM (Pulse Width Modulation) type IC, but the control IC is a PFM (Pulse Frequency Modulation). , Pulse frequency modulation) type chopper type DC / DC converter can also be implemented in the same manner by applying the present invention.

The chopper-type DC / DC converter, which is configured by converting the reactor of the current non-isolated chopper-type DC / DC converter for space into a transformer and can obtain an isolated output, has been described above with reference to FIG. The chopper-type DC / DC converter of FIG. 1 is realized by adding a small number of components to the circuit of FIG. The component shown in the circuit diagram of FIG. 1 surrounded by an elliptical or circular broken line and the inductor L1 are components added to the circuit of FIG.

In FIG. 1, 1 is a control IC, Q1, Q2 and Q3 are n-channel MOSFETs, T1 is a transformer, D1, D2, D3 and D4 are diodes (D2 is an inductor), C1, C2 and C3 are capacitors, and n1. Is the primary winding of the transformer T1 (number of turns: n ₁ ), n2 is the secondary winding of the transformer T1 (number of turns: n ₂ ), and L1 is an inductor for noise removal. Further, A'is a POL application circuit, and the above additional parts (parts shown by an elliptical or circular broken line and inductor L1) are added to the existing non-insulated space POL DC / DC converter (A in FIG. 2). The added circuit B is an additional circuit (same as in FIG. 2) in which the reactor in the existing non-isolated POL DC / DC converter for space is replaced with a transformer T1 so that an insulated output V _{OUT can be obtained.} A DC power supply is supplied between the input terminals V _IN and RTN, and a DC power supply is output _{from between the output terminal + 5V OUT} and the RTN.

The control IC 1 is a PWM (Pulse Width Modulation) type IC, and generates a PWM pulse from the input power supply by applying a PWM control signal to the gates of MOSFETs Q1, Q2 and Q3 and switching the input power supply. do. MOSFETs Q1 and Q3 are turned ON / OFF in synchronization. On the other hand, the MOSFET Q2 is turned ON / OFF in the opposite phase to the MOSFETs Q1 and Q3. That is, Q2 is controlled to OFF during the period when Q1 and Q3 are ON, and Q2 is controlled to ON during the period when Q1 and Q3 are OFF. Although the diode D5 is provided in parallel with Q2 in FIG. 2, the diode D5 is omitted in the embodiment of FIG. Also in the embodiment of FIG. 1, the diode D5 may be provided in parallel with Q2.

When the MOSFETs Q1 and Q3 are turned on _{, the current returns from the input power supply terminal VIN} to the return terminal RTN of the input power supply via the primary windings n1 and Q3 of the transformer T1 and Q1. In FIG. 1, (1) the current path when ON is drawn with a thick line. At this time, the current flowing through the primary winding n1 induces a counter electromotive force in the primary winding n1 and an induced electromotive force in the secondary winding n2 of the transformer T1. An induced electromotive force is induced in the secondary winding n2, but the voltage becomes a reverse voltage with respect to the diode D4, so no current flows in the secondary winding n2.

When the MOSFETs Q1 and Q3 are turned off, the control IC1 turns on the MOSFET Q2. _{The power supply from the input power supply terminal VIN} is cut off by turning off Q1, but an induced electromotive force is induced in the primary winding n1 and the secondary winding n2 by the magnetic energy stored in the transformer T1. This induced electromotive force generates a voltage in the primary winding n1 in the direction of maintaining the current flowing in the primary winding n1 until then, and is in the path of the MOSFET Q2, the primary winding n1, the diode D1, and the inductance L1. A current is passed through the capacitor C2 to charge the capacitor C2. On the other hand, the induced electromotive force induced in the secondary winding n2 generates a voltage in the forward direction of the diode D4, and while charging the capacitor C3, outputs a DC power supply to the outside from between _{the output terminal + 5V OUT and the RTN.} .. In FIG. 1, (2) the current path at the time of OFF is drawn by a thick line.

Since the output terminal + 5V _{OUT and RTN are electrically separated from the input power supply terminals V IN} and RTN by the transformer T1, the power supply output from between the output terminal + 5V _OUT and RTN is an isolated output. When the MOSFETs Q1 and Q3 are ON, the induced electromotive force induced in the secondary winding n2 becomes a reverse voltage with respect to the diode D4, so no current flows through the secondary winding n2, but Q1 and Q3 are OFF. Due to the power charged in the capacitor C3 during the period, power is output from between the _{output terminal + 5V OUT and RTN.} Therefore, the isolated output output from between the output terminal + 5V _OUT and RTN is DC power.

As described above, in the chopper type DC / DC converter of FIG. 1, DC power (isolated output) is output from between _{the output terminal + 5V OUT and RTN by the action of the transformer T1.} The voltage input between the _{input terminals V IN} and RTN in the circuit of FIG. 1 _{is defined as V IN} , the voltage output between the output terminal + 5 V _OUT and RTN is defined as V _OUT, and the PWM control output from the control IC. pulse ON time of a signal and _{t on,} when the OFF time of the pulse and _{t off, V OUT} is determined by the following equation (2).
_{V OUT = (n 2 / n} 1) · (t on / t off) V IN (2)
As shown in equation (2), the voltage _{V OUT} of the isolated outputs can be arbitrarily controlled by the ratio of the ON time _{t on} and OFF time _{t off} in the PWM control signal.

A series circuit of resistors R1 and R2 is connected in parallel with the series circuit of the capacitor C2 and the inductor L1, and the potential at the junction of the resistors R1 and R2 is fed back to the control IC1. The control IC1 controls the pulse width of the PWM control signals (signals applied to the gates of Q1, Q2, and Q3) to keep the potential at the junction point constant. Since the potential at this junction corresponds to the voltage across the capacitor C2, the control IC1 controls the switching of Q1 based on the voltage information across the capacitor C2 to keep the voltage across the capacitor C2 constant. It can be said that it is in control.

A resistor R3 is connected between the gate terminal of the MOSFET Q1 and the gate terminal of the MOSFET Q3, a Zener diode D2 is connected between the source terminal and the gate terminal of the MOSFET Q3, and the diode D3 is connected in parallel with the resistor R3. A PWM control signal divided by the resistor R3 and the Zener diode D2 is applied to the gate terminal of Q3. The Zener diode D2 prevents an overvoltage from being applied to the gate terminal of Q3 and protects the gate terminal. The diode D3 acts to increase the turn-off speed of the MOSFET Q3.

An inductor L1 acting as a low-pass filter for noise removal is inserted in series with the diode D1 between the diode D1 and the capacitor C2. The inductor L1 reduces the surge of the current flowing into the capacitor C2, and improves the regulation of the isolated output output from between _{the output terminal + 5V OUT and the RTN.} The inductor L1 may be ferrite beads or amorphous beads.

In the chopper-type DC / DC converter of FIG. 1, output terminals are provided at both ends of the capacitor C2, and a load device can be connected with the output terminals as non-insulated output terminals. However, the chopper-type DC / DC converter of the embodiment of FIG. 1 has a MOSFET Q3. Q3 is turned ON / OFF in synchronization with MOSFET Q1. Therefore, since the exciting current of the transformer T1 can flow through Q3 while Q1 is ON, it is not necessary to provide a non-insulated output end and connect a load device there.

In the chopper-type DC / DC converter of FIG. 2 described above, an exciting current is supplied to the transformer T1 by connecting a load device between _{the output terminal + 3.3 V OUT and the RTN and passing a load current.} On the other hand, in the chopper type DC / DC converter of the embodiment of FIG. 1, since the exciting current can flow through the MOSFET Q3, a non-insulated output end is provided and a load device is not connected to the non-insulated output end. _{In other words, a load device can be connected between the output terminal + 5V OUT} , which is the isolated output end, and the RTN without consuming power in the additional device at the non-insulated output end, and the insulated output can be provided to this load device. Therefore, the chopper type DC / DC converter of the embodiment of FIG. 1 can output electric power only from the insulated output terminal, and is provided with a non-insulated output terminal to consume power in a load device between the non-insulated output terminals. Since it is not necessary, it has an excellent feature that it can provide an isolated output with high power efficiency.

In the chopper type DC / DC converter for insulation type that does not generate non-insulation output, the insulation output is detected by the photocoupler and the output of the photocoupler is fed back to the control IC to stabilize the insulation output voltage. There are many things. However, photocouplers are generally susceptible to radiation damage, and those having radiation resistance are expensive and have problems in obtaining them.

On the other hand, in the chopper type DC / DC converter of the embodiment of FIG. 1, a series circuit of resistors R1 and R2 is provided on the capacitor C2 side of the diode D1 which is a non-insulated output, and the potential of the connection point of the resistors R1 and R2 is set. The voltage is fed back to the control IC1 as the voltage corresponding to the voltage between the terminals of the capacitor C2 (corresponding to the non-insulated output) to stabilize the voltage between the terminals of the capacitor C2 corresponding to the non-insulated output, and at the same time, the isolated output (output terminal + 5V _OUT). Since the voltage between and RTN) is stabilized, an insulated output of a predetermined voltage can be stably obtained without using a photocoupler. As described above, the chopper-type DC / DC converter of the embodiment of FIG. 1 has an excellent feature that the insulation output can be stabilized without using a photocoupler. Therefore, the chopper-type DC / DC converter of the embodiment of FIG. 1 is suitable for space use.

The chopper-type DC / DC converter of the embodiment of FIG. 1 includes parts (Q3, R3, D2, D3, D1) in the range shown by the dashed lines of an ellipse and a circle in FIG. It is realized by adding the additional circuit B of FIG. 2 as it is to the POL application circuit A'in which the inductor L1 is added. Although the diode D5 in FIG. 2 is missing in FIG. 1, as described above, the diode D5 may be provided in the embodiment of FIG. 1 as well. Further, although the inductor L1 which is not in the circuit of FIG. 2 is provided in the embodiment of FIG. 1, noise is reduced by inserting the inductor L1 to improve the regulation, and the inductor in the circuit of FIG. 1 is also provided. The present invention can be carried out even if L1 is omitted.

FIG. 3 is a circuit diagram of a chopper-type DC / DC converter that summarizes the main points of the present invention. FIG. 3 summarizes the main functions of the chopper-type DC / DC converter of FIG. 1, which is an embodiment of the present invention. The chopper type DC / DC converter of FIG. 3 includes a control IC 1, a DC power supply 10, a first switch element Q1, a second switch element Q3, a rectifying element D6, a first diode D4, and a second diode. It has a diode D1, a primary winding n1, a secondary winding n2, a first capacitor C2, and a second capacitor C3. The primary winding n1 and the secondary winding n2 form a transformer T1. The first load device 30 is connected to the isolated output end of the chopper type DC / DC converter of FIG. The second load device 20 is connected to the non-isolated output end of the chopper type DC / DC converter of FIG.

In the chopper type DC / DC converter of FIG. 3, one terminal of the DC power supply 10 is connected to one terminal of the first capacitor C2, and the other terminal of the DC power supply 10 is connected to the first switch element Q1 and the primary winding. It is connected to the other terminal of the first capacitor C2 via a series circuit composed of the wire n1, and is between one terminal of the first capacitor C2 and the terminal on the primary winding n1 side of the first switch element Q1. A control IC1 is provided in which the rectifying element D6 is connected and the voltage is controlled to be constant by controlling the switching of the first switch element Q1 based on the voltage information across the first capacitor C2, and the primary winding n1 is provided with a control IC1. An electromagnetically coupled secondary winding n2 is provided, and the primary winding n1 and the secondary winding n2 form a transformer T1. A chopper-type DC / DC converter that is connected to the capacitor C3 and the first load device 30 is connected in parallel with the second capacitor C3.
A second diode D1 is inserted in series on the first capacitor C2 side of the primary winding n1, and between the terminal on the primary winding n1 side of the second diode D1 and one terminal of the first capacitor C2. The second switch element Q3 is connected, and the control IC1 is characterized in that the second switch element Q2 is switched in synchronization with the first switch element Q1. The rectifying element D6 corresponds to the MOSFET Q2 of FIG. 1, and can be realized by a diode, or may be configured by a parallel circuit of the MOSFET Q2 and the diode D5 shown in FIG.

FIG. 4 summarizes the main functions of the chopper type DC / DC converter shown in FIG. The circuit shown in FIG. 2 is a chopper-type DC / DC converter that is configured by converting the reactor of the current non-isolated chopper-type DC / DC converter for space into a transformer so that an isolated output can be obtained. Is as described above. The chopper type DC / DC converter of FIG. 4 includes a control IC 1, a DC power supply 10, a first switch element Q1, a rectifying element D6, a first diode D4, a primary winding n1, and a secondary winding. It has a wire n2, a first capacitor C2, and a second capacitor C3. The primary winding n1 and the secondary winding n2 form a transformer T1. The first load device 30 is connected to the isolated output end of the chopper type DC / DC converter of FIG. The second load device 20 is connected to the non-isolated output end of the chopper type DC / DC converter of FIG.

In the chopper type DC / DC converter of FIG. 4, one terminal of the DC power supply 10 is connected to one terminal of the first capacitor C2, and the other terminal of the DC power supply 10 is connected to the first switch element Q1 and the primary winding. It is connected to the other terminal of the first capacitor C2 via a series circuit consisting of wire n1, and is between one terminal of the first capacitor C2 and the terminal on the primary winding n1 side of the first switch element Q1. A control IC1 is provided in which the rectifying element D6 is connected and the voltage is controlled to be constant by controlling the switching of the first switch element Q1 based on the voltage information across the first capacitor C2, and the primary winding n1 is provided. An electromagnetically coupled secondary winding n2 is provided, and the primary winding n1 and the secondary winding n2 form a transformer T1. It is connected to the capacitor C3, and the first load device 30 is connected in parallel with the second capacitor C3. The chopper-type DC / DC converter of FIG. 3 described above is different from that of FIG. 4 described above in the following points. That is, in the circuit of FIG. 3, a second diode D1 is inserted in series on the first capacitor C2 side of the primary winding n1, and the terminal on the primary winding n1 side of the second diode D1 and the first capacitor. Although the control IC1 has a configuration in which the second switch element Q3 is connected between one terminal of C2 and the second switch element Q2 is switched in synchronization with the first switch element Q1. On the other hand, the circuit of FIG. 4 lacks these configurations.

FIG. 5 is a circuit diagram showing an example in which the transformer in the chopper type DC / DC converter of FIG. 1 is converted into a reactor to form a non-insulated buck-boost type chopper type DC / DC converter. As shown in this figure, a non-insulated buck-boost type chopper type that can take out a non-insulated output from between _{the output terminals V OUT} and RTN by using the transformer T1 in FIG. 1 as the reactor n1 and removing the additional circuit B in FIG. A DC / DC converter can be realized.

As described above, the POL application circuit A in FIG. 2 is an existing non-insulated space POL DC / DC converter. Therefore, the POL application circuit A'in FIG. 1 is a non-insulated DC / DC converter realized by adding a small number of components to the existing non-insulated space POL DC / DC converter. In particular, in the embodiment of FIG. 1, the control IC 1 which is an important component is a non-insulated space PWM-IC in an existing non-insulated space POL DC / DC converter. Then, in the embodiment of FIG. 1, the isolated output is obtained by using the transformer T1 as the reactor in the non-isolated space POL DC / DC converter. As described above, in the chopper-type DC / DC converter of the embodiment of FIG. 1, the non-insulated space PWM-IC, other core components, and circuit configuration of the existing non-insulated space POL DC / DC converter are used as they are. However, the isolated output is obtained by changing the output reactor in the non-isolated POL DC / DC converter for space to a transformer.

As described above, the chopper type DC / DC converter of the embodiment of FIG. 1 can share parts with the existing non-isolated space POL DC / DC converter, and can obtain an insulated output with a relatively minor change. can. Therefore, the chopper-type DC / DC converter of the embodiment of FIG. 1 selects additional parts from space parts or only additional parts without performing a large amount of time-consuming and costly environmental resistance test on all parts. It is extremely useful in practical use because it can be mounted on space electronic devices simply by conducting an environmental resistance test and conducting an environmental resistance test for the entire unit.

The configuration of a preferred embodiment of the present invention has been described above. However, it should be noted that such embodiments are merely exemplary of the invention and do not limit the invention in any way. Those skilled in the art can easily understand that various modifications can be made according to a specific application without departing from the gist of the present invention.

1 Control IC
10 DC power supply 20, 30 Load Q1, Q2, Q3 n-channel MOSFET
T1 Transformer D1, D2, D3, D4 Diode C1, C2, C3 Capacitor n1 Primary winding of transformer T1 (number of turns: n1)
Secondary winding of n2 transformer T1 (number of turns: n2)
L1 Inductor for noise removal

Claims (9)

One terminal of the DC power supply is connected to one terminal of the first capacitor, and the other terminal of the DC power supply is connected to the first capacitor via a series circuit including a first switch element and a primary winding. Connect to the other terminal, connect a rectifying element between one terminal of the first capacitor and the primary winding side terminal of the first switch element, and connect the voltage across the first capacitor. A control IC for controlling the voltage to be constant by controlling the switching of the first switch element based on the information is provided, a secondary winding electromagnetically coupled to the primary winding is provided, and the primary winding and the primary winding are provided. The secondary winding constitutes a transformer, a first diode for rectifying and smoothing the voltage generated in the secondary winding and a second capacitor are connected, and the first switch element is alternately controlled to be ON or OFF. A chopper-type DC / DC converter in which the first diode is alternately turned OFF or ON, and the first load device is connected in parallel with the second capacitor.
A second diode is inserted in series with the first capacitor side of the primary winding, and a second diode is inserted between the primary winding side terminal of the second diode and one terminal of the first capacitor. A chopper-type DC / DC converter characterized in that two switch elements are connected and the control IC switches the second switch element in synchronization with the first switch element. The first and second switch elements and the rectifying element are composed of MOSFETs.
The chopper-type DC / according to claim 1, wherein the control IC turns on / off the MOSFET of the rectifying element in a phase opposite to ON / OFF in switching of the MOSFET which is the first switch element. DC converter. The rectifying element is composed of a third diode.
The claim is characterized in that in a loop including the primary winding, the second diode, the first capacitor and the third diode, the forward directions of the second and third diodes are the same. The chopper type DC / DC converter according to 1. A series circuit of the first and second resistors is connected between the terminal on the first capacitor side of the second diode and one terminal of the first capacitor.
Claims 1 to 3 are characterized in that the voltage information across the first capacitor is the voltage between one terminal of the first capacitor and the connection point of the first and second resistors. The chopper type DC / DC converter according to any one of. A third resistor is connected between the gate terminal of the MOSFET which is the first switch element and the gate terminal of the MOSFET which is the second switch element, and the source terminal of the MOSFET which is the second switch element is connected. the zener diode is connected between the gate terminal, the third claims 1, characterized in that a diode is connected in parallel to the resistor of from chopper type DC / DC converter according to any one of 4. A claim characterized in that a low-pass filter for noise removal is provided in series with the second diode between the terminal on the first capacitor side of the second diode and the other terminal of the first capacitor. Item 4. The chopper type DC / DC converter according to any one of Items 1 to 5. The low-pass filter is an inductor, ferrite beads, or amorphous beads connected in series with the second diode between the first capacitor-side terminal of the second diode and the other terminal of the first capacitor. The chopper type DC / DC converter according to claim 6, wherein the Chopper type DC / DC converter is characterized in that. The chopper-type DC / DC converter according to any one of claims 1 to 7, wherein a non-insulated output is obtained by using the transformer as a reactor. The chopper type DC / DC converter according to any one of claims 1 to 7.
An isolated output can be obtained by using a non-isolated space PWM-IC applied to a space POL DC / DC converter as the control IC and using the reactor in the space POL DC / DC converter as the transformer. A featured chopper-type DC / DC converter for space.

Images