COSEL CO.,LTD. : Caution For Safety And Products

Frequently Asked Questions

Q. How to protect DC-DC converter against reverse voltage?

Avoid the reverse polarity input voltage. It will break the power supply. It is possible to protect the unit from the reverse input voltage by assembling the external diode. Please refer to the following.

Fig. 1.1 Example of reverse input voltage protection circuit vol.1

Fig. 1.2 Example of reverse input voltage protection circuit vol.2

Fig. 1.3 Example of reverse input voltage protection circuit vol.3

Table 1.1 Feature of reverse input voltage protection circuit

Fig.#	Operation during applied reverse polarity voltage	Advantage	Disadvantage	Cost
1.1	Normal operation	* Normal output * No component required for reocovery	* Not detectable reverse connection * Diode power loss constantly	High
1.2	No output	* Detectable of reverse connection * No component required for reocovery	* No output after reverse connection * Diode power Loss constantly	Low
1.3	No output Fuse open	* Detectable reverse connection * No diode power loss	* Fuse replacement required for recovery * Overcurrent for an instant	Medium

♦ Discontinued product

♦ Technical Data

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Cosel is one of the world's leading power supply manufacturers offeringhigh-quality, ultra small size AC-DC power supplies,DC-DC converters of the state-of-the-art technologies, and effective andeasy-to-use noise filters.

Cosel is one of the world's leading power supply manufacturers offering
high-quality, ultra small size AC-DC power supplies,
DC-DC converters of the state-of-the-art technologies, and effective and
easy-to-use noise filters.