Delta Electronics DNT04 Test Configurations, Design Considerations, Input Source Impedance, Vi ⋅

TEST CONFIGURATIONS

	TO OSCILLOSCOPE
	L	VI(+)
BATTERY	2	100uF
	Tantalum
		VI(-)

Note: Input reflected-ripple current is measured with a simulated source inductance. Current is measured at the input of the module.

Figure 23: Input reflected-ripple test setup

COPPER STRIP

Vo

	10uF	1uF	SCOPE	Resistive
tantalum		ceramic		Load

GND

Note: Use a 10µF tantalum and 1µF capacitor. Scope measurement should be made using a BNC connector.

Figure 24: Peak-peak output noise and startup transient measurement test setup.

				CONTACT AND
				DISTRIBUTION LOSSES
		VI	Vo
	II				Io
SUPPLY						LOAD
		GND

CONTACT RESISTANCE

Figure 25: Output voltage and efficiency measurement test setup

Note: All measurements are taken at the module terminals. When the module is not soldered (via socket), place Kelvin connections at module terminals to avoid measurement errors due to contact resistance.

η = (Vo ⋅ Io) ⋅100 %

Vi ⋅ Ii

DS_DNT04SIP3A_09262007

DESIGN CONSIDERATIONS

Input Source Impedance

The power module should be connected to a low ac-impedance input source. Highly inductive source impedances can affect the stability of the module. An input capacitance must be placed close to the modules input pins to filter ripple current and ensure module stability in the presence of inductive traces that supply the input voltage to the module.

Safety Considerations

For safety-agency approval the power module must be installed in compliance with the spacing and separation requirements of the end-use safety agency standards.

For the converter output to be considered meeting the requirements of safety extra-low voltage (SELV), the input must meet SELV requirements. The power module has extra-low voltage (ELV) outputs when all inputs are ELV.

The input to these units is to be provided with a adequate time-delay fuse in the ungrounded lead.

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