15:29 SHENZHEN SUNYUAN TECHNOLOGY CO., LTD.
VBXXXXS/D-1W DC-DC CONVERTER
whawsw.aDabteaaSthfereetq4uUe.cnocmy that will superimpose itself over the ripple of the two converters, this can be reduced by using an external
capacitor at the paralleled output. The preferred method of connecting converters in parallel is via series inductors on the output (see
figure 3). This configuration not only has a lower loss of voltage than the diode method, but by suitable choice of inductor and an
additional external capacitor, the beat frequency can be significantly reduced, as will the ripple from each converter. Suitable values
are given in the table below (see table 1), these typically reduce the beat and ripple frequencies by a factor of 10.
One of the main features of the majority of Sunyuan components DC-DC converters is the high galvanic isolation capability. This
allows several variations on circuit topography by using a single DC-DC converter. The basic input to output isolation can be used to
provide either a simple isolated output power source, or to generate different voltage rails and /or dual polarity rails. These
configurations are most often found in data processing, instrumentation and other noise sensitive circuits where it is necessary to
isolate the load and noise presented to the local power supply rails from that of an entire system. Usually local supply noise appears
as common mode noise at the converter and does not pollute the main system power supply rails. The isolated positive output can be
connected to the input ground rail to generate a negative supply rail if required. Since the output is isolated from the input the choice
of reference for the output side can be relatively arbitrary, for example an additional single rail can be generated above the main
supply rail or offset by some other DC value.
Regulated converters need more consideration than the unregulated type for mixing the reference level. Essentially the single supply
rail has a regulator in its positive output rail only, hence referring the isolated ground will only work if all the current return is
through the DC-DC and not via other external components, such as diode bias, resistor feed. Have an alternative return path can
upset the regulation and the performance of the system may not equal that of the converter. In one word, the isolation features are to
generate two completely independent power supply but also united perfectly through the modern technology. This has been widely
used in the application of mixed circuits, A/D, D/A and other circuits that are sensitive to noise.
All Sunyuan isolated DC-DC Converters have a fixed characteristic frequency at which the device operates. This fixed frequency
allows filtering that is relatively simple compared to pulse-skipping types. In a pulse-skipping converter a large range of frequencies
are encountered as the device adjusts the pulse interval for loading conditions.
TEMPERATURE DERATING GRAPH
Safe Operating Area
40 71 85
Operating Temp (Celsius)
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Printed in P.R.C January 2007 Page 3 of 4