I have been working on designing a dual polarity power supply of no more than 20 volts or so @ 1 to 2 amps to use at my workbench at home for some time.
I found the page showing the DCP02 series and I particularly like the DCP020515DP and the DCP021212DP. The data sheet shows a fairly simple installation requiring a good connection to the input power and decoupling capacitors. I was wondering if there are some more detailed circuit ideas and applications for the DCP02 series.
The DCP02XXXX are low current unregulated ,DCP020515DP and the DCP021212DP. very low current 2W converters. The average maximum current for each polarity is about 1W/ 12V wide ranging Vout or 83mA per polarity or 1W/15V 66mA per polarity. the voltage can range between 11.5V to 25V unloaded per polarity These low current converter application exceeds the maximum 1A to 2A current as required .
In reply to Tom Guerin:
Thanks Tom! I forgot to mention that I want to use the DCP02’s to power some op-amps used a voltage followers to boost the input impedance to a DATAQ D-194. I would also like for this power supply to be able to run several things at once. I am using a 24V center-tapped transformer rated at 2 amps and that works out to 48 watts. I have been studying the data sheets on the DCP02’s, UA78xx’s, LM317’s, and LM337’s. They talk about the advantages of using designs that incorporate voltage regulation at the load instead of central regulators having bus-bars.
I have decided on using an LM317 in a shunt configuration able to handle several amps using power transistors as series pass elements. (Fig. 14, page 12 of the LM317 datasheet.) and setting it for 24 volts (VP is 34V). From there I will use DCP02’s for dual polarity to power op-amps and UA78xx’s, LM317/337’s to power whatever else I put on it.
I would like to know if TI has a dual polarity IC able to handle more than 2 watts.
In reply to David Poston:
There are no other dual output devices in the PLUg-in Power line with more than 2W
The DCP022415D is capable of 2W , maximum 1W per polarity .The DCPcan be parallelled for more current per the specification Figure 9. Each dual out put must have configured capacitors as per the figure 8 in the specification . However, the inrush current per each DCP is 1x750mA .
My telephone number is 630-836-2828.
You said that the inrush current per each DCP is 750 mA. Is this current same for all DCP02 family such as DCP021515? Also, I would like to know how much time DCP021515 can support 750 mA as inrush current? Moreover, is it possible to connect the capacitor such as 47 uF at the output of DCP021515? Is there any maximum limitation in installing output capacitor?
In reply to Arash Khoshkbar Sadigh:
The in-rush current is totally dependent upon the dv/dt of the power source.The DCP series regardless of input or output voltages can have in-rush current of up to 750mA. The Input power source can be foreced into current limit during power-up duration. The power source , when in current limit,which is the DCP longer on duration until it is at normal operating voltage. This delay may eventually overstress the DCP and possible thermal damaged can occur.
One recommendation to eliminate the in-rush current is to:
It may require adding a soft start control circuit delaying the start-up of the DCp021515 for 7 msec or until the 15V bus is actively high.This delay will prevent the activation of the 15V bus current limit . Additional input capacitance 100uf may be required to hold-up the 15V bus during the DCP021515Uactive switching transition .This circuit can be added to the input sync. pin,.
I added in an attachment for delaying the start-up of the input voltage 15V, 12V DCP series converters.
Can you also let me know whether it is possible to add capacitor such as 33 or 47 uF at the output of DCP020515DP or DCP021212DP? Is there any maximum limitation of capacitance in installing output capacitor?
The use of a 33uF or 47uf ceramic can affect the operation of the DCP series products. I recommend no more than 10uF low ESR ceramic capacitance on each bus.
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