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COSEL Power Supply, Noise Filter 2025 Product Catalog
DC-DC Converters POL TypeInstruction Manual3.6 Softstart/Start-up sequence!The adjustment of the rise time is possible by connecting C SEQ .!With the voltage to input into SEQ pin, you can control a start sequenceof plural power supplies.(a) The same timeRC+VOUT ARC+VOUT BOFFONCSEQSEQRCGNDVP.S. AGNDRASEQP.S. BGNDFig.3.7 Example of soft start circuit+VOUT A+VOUT BV RC A!When the voltage is applied to the terminal SEQ, the output voltagetracks this voltage until the output reaches the set-point voltage.SEQ terminal voltage vs output voltage is calculated the followingformula.Avoid SEQ terminal voltage is set below the set voltage output byRtrm, the output voltage does not rise to set output voltage. Maximumapplicable voltage of terminal SEQ is Vin.When the functionis not used, open terminal SEQ.(b) The same voltage+VOUT ARCP.S. AGNDVRA+VOUT BRCSEQP.S. BGNDtC SEQ [mF] = (0.284÷Vo[V] - 0.06)×T[ms](0.6V [ Vo [ 2.0V)C SEQ [mF] = (0.284÷Vo[V] - 0.047)×T[ms](2.0V < Vo [ 3.63V only BRFS30)VOUTSettingSEQVOUT(c) The time lag+VOUT ARCP.S. AGND+VOUT A+VOUT BV RC A+VOUT BRCSEQP.S. BGNDtFig.3.8 SEQ > Vout settingV+VOUT A+VOUT BV RC AVOUTSettingSEQVOUTtFig.3.10 Example of sequence control!If this function is unnecessary, please make SEQ pin open.!It is not possible to shorten the rise time when not using this function.Fig.3.9 SEQ < Vout setting (not recommended)3.7 Power good!By using PGOOD, it is possible to monitor power supply whethernormal operation or abnormal operation.!PGOOD circuit is designed as shown in Fig.3.11.Sink current of PGOOD is 10mA max.BRFS/BRDS-19
