Delta Electronics Series 240W manual Design Considerations, Features Descriptions

DESIGN CONSIDERATIONS

Input Source Impedance

The impedance of the input source connecting to the DC/DC power modules will interact with the modules and affect the stability. A low ac-impedance input source is recommended. If the source inductance is more than a few μH, we advise adding a 33 to 220μF electrolytic capacitor (ESR < 0.5 Ω at 100 kHz) mounted close to the input of the module to improve the stability.

Layout and EMC Considerations

Delta’s DC/DC power modules are designed to operate in a wide variety of systems and applications. For design assistance with EMC compliance and related PWB layout issues, please contact Delta’s technical support team. An external input filter module is available for easier EMC compliance design. Below is the example of using Delta latest FL75L10 A input filter tested with E48SB12020 to meet class B in CISSPR 22.

Schematic and Components List

C2	C1	E48SB12020	Load
Vin	FL75L10 A	Series
		C3

C1 is 100uF/100V, low ESR Aluminum cap;

C2 is 2.2uF ceramic cap;

C3 is 4.7nF ceramic capacitor;

FL75L10 A is Delta input EMI filter module.

Test Result

Test result is in compliance with CISPR 22 class B, which is shown as below:

Vin=48V, Io=20A, average mode

Soldering and Cleaning Considerations

Post solder cleaning is usually the final board assembly process before the board or system undergoes electrical testing. Inadequate cleaning and/or drying may lower the reliability of a power module and severely affect the finished circuit board assembly test. Adequate cleaning and/or drying is especially important for un-encapsulated and/or open frame type power modules. For assistance on appropriate soldering and cleaning procedures, please contact Delta’s technical support team.

FEATURES DESCRIPTIONS

Over-Current Protection

The modules include an internal output over-current protection circuit, which will endure current limiting for an unlimited duration during output overload. If the output current exceeds the OCP set point, the modules will automatically shut down, and enter in hiccup mode or latch mode, which is optional.

For hiccup mode, the module will try to restart after shutdown. If the overload condition still exists, the module will shut down again. This restart trial will continue until the overload condition is corrected.

For latch mode, the module will latch off once it shutdown. The latch is reset by either cycling the input power or by toggling the on/off signal for one second.

DS_E48SB12020_05222008

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