DC891A

Demonstration circuit 891 is a high current capacitive charging circuit featuring the LT3750EMS. It is a DC/DC flyback converter used to charge large capacitors to high voltages. The circuit implemented on the board is a simple example of how to charge a 400uF capacitor to 300V in approximately one second, depending upon the line and load conditions. An output capacitor discharge circuit is included on the board for the convenience of the user. This discharge circuit can be disabled by the user or permanently enabled at the expense of a minor degradation in the charging profile. The LT3750 is a current-mode flyback controller optimized for charging large value capacitors to a predetermined target voltage. This target voltage is set by the turns ratio of the flyback transformer and just two resistors in a simple, low voltage network, so there is no need to connect components to the high voltage output.

• Input voltage range from 6 to 20VDC (Vout = 0 to 320V)
• Output target voltage 300 + 5%VDC at Vin = 6 to 20VDC
• Average input charging current of 2.2A (Vin = 0 to 20V, Cload = 400uF )

Warnings

Lethal voltages are present on the DC891 circuit board. do not operate the assembly unless you are trained to handle high voltage circuits.

Notes

ADI products are only authorized (and sold) for use by the customer and are not to be resold or otherwise passed on to any third party