DCE001‐*

DC/DC Converter
Application Manual1Consideration Needed for Safety Design
While our company has made significant effort to improve the quality and reliability of our products,
semiconductor application products cannot be completely free from faults and malfunctions.
Therefore, extreme care needs to be taken for safety design – for example, redundancy design, fire
spread prevention design, and malfunction prevention design – so that fault or malfunction of oursemiconductor application products will not result in an incident such as a fatal accident, fire
accident, and social problem.

Important Notes for Use of This Document‐ This document aims to help you choose and purchase our appropriate products which meet yourapplications. Regarding the technical information provided on this document, the implementation
and use of intellectual property rights and other rights which have been possessed by our company
are not granted by the document.
‐ Our company shall not be liable to a damage which attributes to the use of the product data,
figures, tables, programs, algorithms, and circuit application examples which are presented in thisdocument and to violation of rights possessed by third parties.
‐ The product data, figures, tables, programs, algorithms, and all other information presented inthis document are those which were the latest when the document was generated. These aresubject to change without notice for reasons such as improvement of characteristics. Therefore,
before purchasing our products, check the latest information with our sales representative.
‐ When using technical information shown in the product data, figures, and tables in this document,
perform thorough evaluation from the perspective of the entire system besides the technicalinformation itself, and judge on your account whether the technical information is applicable. Our
company shall not be liable to the applicability of our products.
‐ The products described in this document have not been designed and produced for use withequipment or system which is operated in an environment which involves human lives. If intending
to use the products, for special purposes – for example, transportation, medical applications,aerospace, nuclear power control, and submarine relay equipment or systems, contact our sales
representative.
‐ Reprint or reproduction of this document needs our written permission.
‐ For any inquiry about the contents written in this document, contact our sales representative.

ISAHAYA ELECTRONICS CORPORATION

2Contents■ Feature of ISAHAYA ELECTRONICS DC/DC Converter◇ Features

・・・・・・・・・・・4p◇ Product Range

・・・・・・・・・・・4p◇ Product Tree

・・・・・・・・・・・4p■ Important Notes for Use
1. Connection Terminals

・・・・・・・・・・・5p

2. Connection Methods
2.1. Basic Connections
2.2. Serial/Parallel Connections
2.3. Peripheral Connections

・・・・・・・・・・・5p
・・・・・・・・・・・5p
・・・・・・・・・・・5~7p

3. Functions
3.1. Overcurrent Protection
3.2. Overvoltage Protection
3.3. Isolation Voltage

・・・・・・・・・・・7p
・・・・・・・・・・・7p
・・・・・・・・・・・8p

4. Mounting
4.1. Mounting Method
4.2. Pattern Layout
4.3. Heat Radiation

・・・・・・・・・・8p
・・・・・・・・・・8p
・・・・・・・・・・8p■ How To Read Data Sheets◇ Block Diagram

・・・・・・・・・・・9p◇ Maximum Rating・・・・・・・・・・・9p◇ Electrical Characteristics

・・・・・・・・・・10p◇ Measurement Circuit

・・・・・・・・・・10p◇ Typical Characteristic Curve Examples

・・・・・・・・・・11p

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ISAHAYA ELECTRONICS DC/DC Converter【Features】■ Broad product lineup
The wide variety of available products includes isolation types, non‐isolation types, low‐voltage input types, and high‐voltage input types.
■ Extensive inverter‐peripheral products
Especially products for inverter control and products for inverter‐peripheral product control allow extensive selections.
■ Lineup of small, high‐isolation‐voltage products
Despite the small size, the isolation voltage is 2,500Vrms.
■ Lineup of high‐voltage wide input products
Isolation‐type DC/DC converter series which is able to input up to 1,000VDC is available.
【Product Range】
Besides the main products – isolation‐type DC/DC converters such as IGBT drive gate power supply and IPM control power
supply–, peripheral‐equipment control power supply and high‐voltage input type pre‐regulators are available. A wide range ofpower supply have been commercialized through the employment of the single inline (SIL) structure, dual inline (DIL) structure,
TWIN structure, and the combinations of these structures resulting in a small‐unit structure.
Input Voltage
(VDC)
1000
800

SIL + TWIN
Small‐Unit Structure
SIL Structure400
DIL Structure

200

TWIN Structure

1

10

100

Output Capacity (W)【Product Tree】
For 100AC System
For 200AC System
High‐Voltage Input
For 400AC System
Isolation Type (DC/DC converter)

High-Voltage Wide-Input TypeLow‐Voltage Input
For 200AC System
High‐Voltage Input
For Common Use for 100V and
200VAC System

Non‐Isolation Type (DC/DC converter)
Low‐Voltage Input

4Important Notes for Use
1. Connection Terminals
Depending on the product shape, the connection terminals of the DC/DC converter are lead pins, connectors, and terminal
blocks. For the terminal numbers and terminal names, see the data sheet of the relevant product. When making connections,
properly identify the indicated terminal placement, so that product damage and deterioration due to wrong connections are
avoided. Be careful that energization with wrong connections made may result in a short‐circuit fault.

2. Connection Methods
2.1 Basic Connections
To use the DC/DC converter, basically the connections shown in Figure 2.1 have to be made. For peripheral components needed
for the product, see the data sheet for the product.
The DC/DC converter can be used only through DC input. Directly connecting to AC input causes the product to malfunction, andthus never connect to AC input directly.
If attempting to use AC input, connect a rectification smoothing circuit to the input portion as shown in Figure 2.2. Because theinput voltage range of the DC/DC converter is the one after rectification smoothing, use within the input voltage rating of the
DC/DC converter.
Input (+)

Input (+)

Output (+)

DC power

Load
Input (–)

AC power

Output (+)

Rectificationsmoothing

Load
Input (–)

Output (–)

Figure 2.1 Input/Output Connection Method

Output (–)

Figure 2.2 For AC Input Connections

2.2 Serial/Parallel Connections
Basically, the DC/DC converter does not allow serial connections and parallel connections. If considering such connections for the
product, contact our sales representative.
Input (+)

Output (+)

Input (+)

Output (+)
LoadInput (–)

Output (–)

Input (–)

Output (–)

LoadInput (+)

Output (+)

Input (+)

Output (+)

Input (–)

Output (–)

Input (–)

Output (–)

Figure 2.3 Serial Connections

Figure 2.4 Parallel Connections

2.3 Peripheral Connections
1) Input‐side connections■Electrolytic Capacitor‐ To stabilize the operation of the DC/DC converter, put an electrolytic capacitor between the input (+) and input (–).
‐ For the capacitance of the electrolytic capacitor, check with the measurement circuit on the data sheet of the relevant product.
‐ Place the electrolytic capacitor as close to the product as possible.
Input (+)

Output (+)＋

DC power

Load
Input (–)

Output (–)

Figure 2.5 Input‐Side Capacitor Connection

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Important Notes for Use■ FuseSome DC/DC converters contain fuses but the others do not contain them. No matter whether a fuse has been contained,
attach a fuse to the input (+) to secure safety.
When the fuse has brown out, the product may have malfunction. Therefore, do not energize the product after replacing thefuse.
■ Prevention of Reverse Connections
In a case where voltage of reverse polarity may be applied to the input side, add a protection circuit as shown in Figure 2.6.
Output (+)

Input (+)
DC power

Load
Input (–)

Output (–)

Figure 2.6 Fuse addition/reverse connection prevention example■ Reduction of Mains Terminal Interface Voltage
The DC/DC converter does not contain a filter circuit. To reduce mains terminal interface voltage, connect an external filter circuit.
Input (+)
DC power

Output (+)

Filtercircuit

Load
Input (–)

Output (–)

Figure 2.7 Filter Circuit Connection2) Output‐side connection■ Electrolytic Capacitor‐ To stabilize the operation of the DC/DC converter, put an electrolytic capacitor between the output (+) and output (–).
‐ For the capacitance, check with the measurement circuit on the data sheet of the relevant product.
‐ Choose an electrolytic capacitor which has good harmonic characteristics.
‐ When choosing an electrolytic capacitor, be careful with the ripple current rating.
‐ Place the electrolytic capacitor as close to the product as possible.
Input (+)

Output (+)＋

DC power
Input (–)

Load

Output (–)

Figure 2.8 Output‐Side Capacitor Connection■ Resistor/Capacitor
Some models allow output voltage to be changed with an external resistor. Check with the measurement circuit on the data sheetof the relevant product.
Input (+)

Output (+)
Output voltage
setting terminal

DC power
Input (–)

Resistor

Load

Output (–)

Figure 2.9 Voltage setting resistor connection example

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Important Notes for Use3) Other peripheral connections■ CoilSome models require a coil to be placed. Check with the measurement circuit on the data sheet of the relevant product.
Depending on the placement of the coil, the characteristic may change. See the pattern layout in Section 4.2.

Input (+)

Output (+)＋＋

DC power
Input (–)

Load

Output (–)

Figure 2.8 Connection of External Coil

3. Functions
3.1. Overcurrent Protection
The characteristics of the DC/DC converter during overcurrent occurrence differ depending on the product. The operations are shownin the figures below:
Overcurrent
Overcurrent
Overcurrent
Rated current setting value
Rated current setting value
Rated current setting value

Figure 3.1 Fold‐back Current
Limiting Characteristic

Figure 3.2 Drooping Characteristic

Figure 3.3 Fold‐Forward Current
Limiting Characteristic

The setting has been made so that overcurrent protection starts to function when current becomes 1.1 times larger than the rated
current. The operation differs depends on each characteristic at larger than the overcurrent setting value.
‐ For the fold‐back current limiting characteristic, both of the output voltage and output current decrease when overcurrent flows.
‐ For the drooping characteristic, the output voltage decreases when overcurrent flows. The output current remains uniform near theovercurrent setting value.
‐ For the fold‐forward current limiting characteristic, the output voltage decreases but the output current increases.
The fold‐back current limiting characteristic and the drooping characteristic are acceptable. However, the fold‐ forward current limiting
characteristic does not allow current restriction and thus it must be avoided: especially in short‐circuit status, the product may bedamaged.
Any of these characteristics allows automatic recovery when overcurrent status is ended.
Typically, the DC/DC converter contains an overcurrent protection function. However, avoid continuous use of the converter at the timeof overcurrent flow or in short‐circuit status, to prevent product damage and life reduction.
For the presence/absence of an overcurrent protection function and the characteristic at the time of overcurrent flow, check with thedata sheet of the relevant product.
3.2. Overvoltage Protection
Some DC/DC converters contain an overvoltage protection function. Check with the data sheet of the relevant product. Because of thelatch mode, recovery is made regarding overvoltage protection when input voltage is applied again.
The overvoltage protection function serves to protect the product so that overvoltage is not applied to the load when high voltage is
generated at the output side due to malfunction of internal components (etc.). Therefore, overvoltage operation check at acceptanceinspection and application of voltage which exceeds output voltage from the output side has not been assumed. Avoid such check anduse because the product is exposed to stress and may be damaged.

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Important Notes for Use
3.3. Isolation Voltage
The isolation voltage of isolation‐type DC/DC converters differs depending on the product. Check with the data sheet of the relevant
product.
When an isolation voltage test is conducted at an occasion such as acceptance inspection, increase and decrease the voltage gradually.

4. Mounting
4.1. Mounting Method
Depending on the product shape, the connection terminals of the DC/DC converter are lead pins, connectors, and terminal blocks.
For the soldering of the lead pins, see the flow conditions and soldering conditions described in other relevant sections.
Regarding connector and terminal block attachment, information (type name) on the connectors and terminal blocks is shown on thedata sheet of the relevant model. Use the matching connectors, screws, and terminals.

4.2. Pattern Layout
The size of lead pins differs depending on the product. Check with the outline diagrams on the data sheet or the outline diagram forthe relevant model. When designing, be careful with the appropriateness of the hole diameter.
Separate the input side and the output side, makes the line short, and be careful not to make a loop.
For a product to be attached with an external coil, the placement of the coil may affect the characteristics. Therefore, as the layout in
Figure 4.1 shows, place the coil at the opposite side of the electrolytic capacitors and GND line across the product.
Also, for the peripheral circuit, be careful not to make the GND line pass near the coil.
Coil
Input terminal GND terminal

Output terminal

8

DC/DC converter

Coil connection terminal

Input‐side electrolytic capacitor

Output‐side electrolytic capacitor

Figure 4.1 Placement of External Coil4.3. Heat Radiation
Regarding the DC/DC converter, natural cooling has been assumed. While the attachment orientation is not specified, avoid mounting theconverter in a sealed place or onto a unit which is not subjected to air convection flow. When using, be careful with the ambient
temperature of the DC/DC converter.
For some models, usable current is restricted by operating ambient temperature. See the derating characteristics on the data sheet of therelevant product.

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How To Read Data Sheets【Block Diagram】
Block diagrams show product circuits for each functional block. They provide the following information:‐ Terminal numbers and terminal names‐ Functions and circuit methods of main components‐ Isolation components (transformer, opto‐coupler, etc.) in isolation circuit
Terminal number

Block Diagram

Isolation part (Transformer)*1

Main component

Circuitfunction

Terminal nameConstant
voltage circuitBase drive
circuitMain component

NC pin*2Overcurrent
protection
circuitOpto‐coupler

Circuit function

9
Isolation part

*1 The black circles of the transformer indicate the polarity.
*2 Do not make any electrical connections to the NC pin and TETS pin. Electrical connections may result in product malfunction.

【Maximum Rating】
When the rating values shown in the table below are exceeded, the product may be damaged.

■ Input voltage: Designates the maximum voltage which can be input to the product. If the rating is exceeded, the product may
be damaged.
■ Output current/load current: Designates the current value which allows safe operations. If the rating is exceeded, the productmay be overheated and damaged. For a product which contains an overcurrent protection function, the function starts to workwhen the current becomes 1.1 times larger than the rated current.
■ Operating ambient temperature: Designates the ambient temperature which assures the product’s specifications and allows
safe product operations.
For models which need derating of the output current, see the derating characteristics. Note that this condition assumes natural
cooling.
■ Storage temperature: Designates temperature which assures appropriate storage in non‐running status. If storing for an
extended period of time, the following conditions are recommended: 5 to 30C and 40 to 60%RH.
9■ Isolation voltage: Designates a value assured for isolation voltage between primary and secondary.

How To Read Data Sheets【Electrical Characteristics】
The values designate specifications which indicate the performance of the product. The specifications are based on the measurement
circuit described later and assume ordinary temperature (Ta = 25 C).
Electrical Characteristics (VIN = 24V, Ta = 25C unless otherwise specified)■ Input voltage: Designates the range which assures safe operations. Even if a recommended range is not indicated and the indicatedmaximum input voltage value is the same as the maximum rating, use of the product with voltage below the maximum rating is
recommended.
■ Output voltage: Designates an output voltage value and its precision. The value is based on the specified input voltage and loadcondition. For the load condition, the minimum current may have been specified. In this case, note that the precision is assured
regarding output voltage under the condition of the minimum current.
In the case of multiple outputs, the value is written for each output. In the case where the load condition of multiple outputs has been
specified, the condition is followed.
■ Input regulation: Designates static input fluctuation and indicates the maximum value of the fluctuation of output voltage which is
generated when the input voltage is slowly changed within the extent of the specifications.
■ Load regulation: Designates static load fluctuation and indicates the maximum value of the fluctuation of output voltage which is
generated when the output current is slowly changed within the extent of the specifications.
■ Ripple voltage: Represents elements which synchronize with input frequency and switching frequency that are superimposed onto
output voltage, and indicates the maximum value which is resulted when the electrolytic capacitor shown in the measurement circuit
diagram has been connected. Noise content is not included in the specifications.
■ Efficiency: Designates the ratio of the output power and input power. For multiple outputs, the value designates the ratio relative
to the total power of the individual outputs.
【Measurement Circuit】
This is a connection circuit for measurement of electrical characteristics. The circuit shows external components which are needed forindividual terminals (e.g., input side and output side). Referring to the circuit is also recommended in terms of peripheral components
at the time of unit incorporation.
For the selection of peripheral components, see Section 2.3 Peripheral Components.
<For measurement><For measurement><For measurement>
Ammeter
Load device
Input power supply

Load<External component>
Input‐side electrolytic capacitor<External component>
Output‐side electrolytic capacitor<For measurement>
Voltmeter

10How To Read Data Sheets【Typical Characteristic Curve Examples】
These are graphs which show the characteristics of individual products. Except for derating characteristics, typical examples
are shown.
Output Voltage‐Output Current Characteristics

Output Voltage Vo (V)Output Current Io (mA)

Derating Characteristics

Ambient Temperature Topr ( C)

Output Current Io (mA)

Efficiency‐Output Current Characteristics

Efficiency‐Input Voltage Characteristics

Efficiency

Efficiency(%)

A graph regarding output voltage‐output current characteristics
show operations at the time of overcurrent flow. Note that thevalue which triggers current restriction differs depending on
specifications.

(%)

A graph regarding derating characteristics shows the restrictionof the load current relative to the ambient temperature. Use
the product with values within the range enclosed by the line.

Input Voltage VIN (V)Output Current Io (mA)

A graph regarding efficiency‐input voltage characteristics shows
the change of the efficiency relative to the input voltage.

Output Voltage‐Input Voltage Characteristics

Input Current‐Input Voltage Characteristics

Output Voltage Vo (V)Input Current IIN (mA)

A graph regarding efficiency‐output current characteristics shows
the change of the efficiency relative to the output current.

Input Voltage VIN (V)A graph regarding output voltage‐input voltage characteristics
shows input voltage at which output voltage becomes constant. The
output voltage becomes constant at voltage which is below the
input voltage range shown for electrical characteristics. However,
use the product within the input range of the electricalcharacteristics.

Input Voltage VIN (V)A graph regarding input current‐input voltage characteristics
shows the input current relative to the input voltage. Use as a
guide to determine the supply capacity of the input power supply.
The input current is not included in rush current which flows at
the time of initiation.

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