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Negative voltage generation with DCV010512D

jean-michel herve
Prodigy 40 points
Other Parts Discussed in Thread: DCV010512D

I designed a board with 2x DCV010512D to generate +24V and -24V. For the +24V, no pb it works fine.

But for the -24V, I mesured ~-4V:

I connected the input on 0/+5V.

The +Vout is used as ground reference and -Vout as -24V.

I loaded the outputs with 1uF capacitor and 10kohm  resitor between 0V and +Vout pins and also between 0V and -Vout.

I connected Sync_in pin of the 2 chip as is discribed in the datasheet (I tried also to disconnected it with the same behavior).

Someone can help me, please?

  • 0
    TI__Mastermind 38230 points

    The DCV01XXXXD, dual converter when configured for 24V , whether it is (+)24V or (-)24V must have the  two ceramic capacitors (1-2.2uF) connected to (Vout (0)) common from each output polarity. The attachment identifies  in figure 2 this configuration .

    Questions on thisapplication are:

    1. What is the voltage potential difference between Vin ground  and Vout ground?

    Example, is the voltage  on the primary or secondary ground greater than 42V AC

    2. What is  the  power source (5V) current capability during power -up ?

    Tom

     

    Pages from DCP01xxxxxProduct specification fig2 dual output.pdf
  • 0 in reply to Tom Guerin
    Prodigy 40 points

    1602.24V_generation.pdf

    The capacitor put on the board are ceramic ones.

     

    1. What is the voltage potential difference between Vin ground  and Vout ground?

    The potential voltage between Vin_ground at 0V, Vout+= -6.5V , Vout- = 0V and Vout_0V= 3.3V (in fact I have a sine wave between 3.1 and 3.5V) .

    2. What is  the  power source (5V) current capability during power -up ?

    I have and external power supply. It's Lab supply From Agilent. I tried another supply with the same result.

     

    Note: I attached the schematic of my design. The top chip is dedicated for the +24V and the other one is for -24V.

     

    Jean-Michel

  • 0 in reply to jean-michel herve
    TI__Mastermind 38230 points

    Hi Jean- Michel:

    I reviewed the schematic .

    1. I would initially evaluate the load on the (-)24V including the 10kΩ resistors?

    The absolute maximum current is 41mA for the + or (-) 24V application .

    Contact me at e-mail address of tguerin@ti.com

    I can call you to discuss this application

    tom

  • 0 in reply to Tom Guerin
    TI__Mastermind 38230 points

    Jean-Michel additional  data to the above reply.

    I reviewed and restested this +24V and (-) 24 V application as received from you.

    The +24V and -24V DCP010512DBP function normally with a 35mA load on each ±24V bus.the average voltage at the maximum load is about ±22.9V at 35-40mA load each voltage .

    1. One suggestion is to ohm out the  load on the -24V regulator. and compare this resistance data( Note watch polarity of the meter probes)  to the +24V regulator, pin to pin measurement.s .

    A. Pin 6 to pin 7 ohms  in both directions

    B. Pin 5-to pin 7 both directions

    C pin 5 to pin 6 both directions.

    D. Then measure the resistance between -24V pin 7 and +24V pin 6 for additional loading.

    Best regards

    Tom