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DRV110: DRV110

Bijendra Verma
Prodigy 40 points
Part Number: DRV110

I have assembled the schematic of DRV110 to work on supply of 110V dc to connect to coil of a solenoid.

Though the assembled PCB is working with expected peak and hold currents but there is following problems.

1). If I use the OSC resistance = 0 ohms, I get a freq of 20KHz at the MOSFET.      BUT the MOSFET gets heated up.

On the other hand when

2). If I use the OSC resistance = 2M ohms, I get a freq of 1.8 KHz at the MOSFET.  Now the MOSFET is warm but now there is a lot of humming noise from the solenoid.

3). If I use the OSC resistance = 30M ohms (experimental, though not recommended), I get a freq of 164 Hz at the MOSFET.  Now again the MOSFET is cool but now again there is a lot of humming noise from the solenoid.

Please ask me for any design data  required to resolve the problem.

Looking forward to any help to resolve the problem.

Regards,

  • 0
    Prodigy 40 points

    PS:    To clarify further, I need to help for the problem such that there should be no noise and MOSFET should not heat up.

  • 0 in reply to Bijendra Verma
    TI__Expert 6330 points

    Hi,

    I have notified our expert regarding this topic. Please expect a response by 9/20/19.

    Thanks,

    Aaron

  • 0
    TI__Expert 4940 points

    Hi,

    Seems to me that's a MOSFET slow  Tr/Tf issue based on your experiment. At high frequency the % of time during transition is higher and the MOSFET will heat up.

    The typical DRV110 max gate drivability is +/-15mA

    Regards,

    Costin

  • 0 in reply to Costin Cazana
    Prodigy 40 points

    Hi Costin,

    Thanks for your response. I am using MOSFET  STP13N80K5. It has the following Tr and Tf data. Tr/Tf = 1 in this case.                         

    Symbol

    Parameter

    Test conditions

    Min.

    Typ.

    Max.

    Unit

    td(on)

    Turn-on delay time

    VDD= 400 V, ID = 6 A, RG = 4.7 Ω, VGS = 10 V

    (see Figure 21: "Test circuit for resistive load switching times" and Figure 26: "Switching time waveform")

    -

    16

    -

    ns

    tr

    Rise time

    -

    16

    -

    ns

    td(off)

    Turn-off delay time

    -

    42

    -

    ns

    tf

    Fall time

    -

    16

    -

    ns

     

    Do you suggest any other MOSFET for the following voltage and resistance.

    The solenoid working voltage is 220V.

    Coil dc resistance = 48 ohms

    Coil inductance (with armature placed at position resembling fully operated condition) = 1.36 Henry

     

    2). Also please suggest how can I reduce the duty cycle.

    I get a fixed duty cycle of about 90%, for any value of Rs that I may use.

    Present value of Rs=0.1 ohms and series resistance (from Rs to IC sense pin 9 = 20K).

    Other values are as under:

    R peak= 39K

    R hold= 500K

    C keep= 1 uF

    Looking forward to any help.

    Thanks again for your support.

     

  • 0 in reply to Costin Cazana
    Prodigy 40 points

    Hi Costin,

    Thanks for your response. I am using MOSFET  STP13N80K5. It has the following Tr and Tf data. Tr/Tf = 1 in this case.                         

    Symbol

    Parameter

    Test conditions

    Min.

    Typ.

    Max.

    Unit

    td(on)

    Turn-on delay time

    VDD= 400 V, ID = 6 A, RG = 4.7 Ω, VGS = 10 V

    (see Figure 21: "Test circuit for resistive load switching times" and Figure 26: "Switching time waveform")

    -

    16

    -

    ns

    tr

    Rise time

    -

    16

    -

    ns

    td(off)

    Turn-off delay time

    -

    42

    -

    ns

    tf

    Fall time

    -

    16

    -

    ns

     

    Do you suggest any other MOSFET for the following voltage and resistance.

    The solenoid working voltage is 220V.

    Coil dc resistance = 48 ohms

    Coil inductance (with armature placed at position resembling fully operated condition) = 1.36 Henry

     

    2). Also please suggest how can I reduce the duty cycle.

    I get a fixed duty cycle of about 90%, for any value of Rs that I may use.

    Present value of Rs=0.1 ohms and series resistance (from Rs to IC sense pin 9 = 20K).

    Can we get a duty cycle of about 50%.

    Other values are as under:

    R peak= 39K

    R hold= 500K

    C keep= 1 uF

    Looking forward to any help.

    Thanks again for your support.

  • 0 in reply to Bijendra Verma
    TI__Expert 4940 points

    Hello,

    The solenoid current Tr/Tf is set by : the solenoid inductance and resistance, supply voltage and target Ipeak and Ihold.

    This time constant is significantly slower that MOSEFET Tr/Tf. Most of the power across the MOSFET is dissipated during transition. Since Tr/Tf is not affected by frequency, at high PWM frequency MOSFET power is higher. Based on worst condition MOSFET Tj you may need a heat sink or/and bigger MOSFET

    The duty cycle is also set by system di/dt/. DRV110 internal comparator has hysteresis, a slow ramping voltage across Rs due to slow current will forced DRV110 Out on until comparator input reaches the turn off threshold

    Another issue is Rpeak and Rhold both are outside recommended values.

    Rpeak should be > 67kohm or grounded

    Rhold should be <333kohm

    Regards,

    Costin