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Driver for +24V/30W cartridge heater

Chris van der Aar
Intellectual 570 points
Other Parts Discussed in Thread: DRV8847, TPS92520-Q1, DRV110, DRV103, DRV8803, DRV8860, DRV120

For controlling the temperature of a cup filled with liquid ethane we have to control the temperature between -160C and -180C. Therefore we will use a temp sensor and a cartridge heater to maintain the temperature of the ethane around -160C.  The heater is a small cartridge type (resistance wire in a small 1/8"tube) and will work at +24V/30W max. So we are looking for a controller (preferably with I2C interface because we want this to control by a PC with USB to serial bridge) that can handle this. Maybe you have a suggestion for a suitable controller? Or do you think a LED driver would be better for this function compared with a motor/solenoid driver?


Regards

Chris van der Aar

NTS-Group

Eindhoven, The Netherlands

  • 0
    TI__Guru** 114905 points

    Hi Chris,

    There are no motor drivers with I2C available at 24V.

    The closest match with IC2 is the DRV8847 which has a recommended max voltage of 18V.

    May we ask a few additional questions to help your selection:

    1) How do you want the device to control the current?
       a) By controlling the inputs?
       b) By controlling the current (using current regulation)?

    2) How do you intend to connect the heater cartridge?
       a) One end connected to GND with the motor driver in half bridge mode?
       b) One end connected to supply with the motor driver in half bridge mode?
       c) A full bridge configuration?

    3) Any other requirements that may allow us to narrow your choices?

  • 0 in reply to Rick Duncan
    Intellectual 570 points

    At this moment it looks that SPI is a better alternative for us because we have to measure temperature and most ADCs for this have SPI interface. We also have I2C on our board for other things but for this part I think we need SPI.

    We want to control the current by current regulation. For connecting the heater cartridge we have several options but I think one end connected to GND will be preferred.

    At this moment our customer uses a Watlow heater but we can always choose another type but it will be probably the same as this one:

    https://www.therm-x.com/watlow-firerod-cartridge-heater-c1a-9602.html  

    So I don't know if T.I.  has drivers for a +24V/30W heater with constant current control? Or do you think we could better choose a LED driver for this? For us it is important that we can control the temperature via a PC (with SPI interface or something similar) so we have to control the current through the heater based on the measured temperature (this will be measured by a temp sensor  and interface with probably SPI but we are in feasibilty phase now).

    Regards


    Chris van der Aar

    NTS-Group

    Eindhoven, The Netherlands

  • 0 in reply to Chris van der Aar
    TI__Guru** 114905 points

    Hi Chris,

    The DRV8881E with AutoTune (No SPI) may work in your application. Assuming the FIREROD is mostly resistive, adding an inductor in series with the outputs would help regulate the current.

    LED Drivers may be a better choice. The TPS92520-Q1 has a SPI interface. I know little about this device. It if looks interesting, we can contact the group responsible for more information or possibly a better alternative.

  • 0 in reply to Chris van der Aar
    Intellectual 570 points

    Ok thanks. I just posted the same question in the power management forum and asked for a suitable (LED?) driver so probably one of the technicians over there will handle this further on.

    In the meanwhile I was also looking for a suitable solenoid driver for a +24V/10W solenoid because we also need to control a solenoid in our system. Therefore I found the DRV103 and DRV110. I think both devices will work but the DRV103 has a higher cost price compared with DRV110. The advantage of the DRV103 is of course that we don't need an external MOSFET for driving the solenoid. Are there any other advantages or disadvantages when comparing these devices? 

    Furthermore we need to control a +24V relay (around 300mA I guess but relay has to be selected). For that function I could of course use the same driver but I think there are cheaper options for controlling +24V relays? Do you have suggestions for controlling a +24V relay? 

    Regards

    Chris van der Aar

  • 0 in reply to Chris van der Aar
    TI__Guru** 114905 points

    Hi Chris,

    We will contact the group responsible for the DRV103 and DRV110 to answer your questions.

    With respect to relays, are you only controlling one? If you are controlling several, there are a couple of options to consider.

    The DRV8803 can control 4 relays, or the DRV8860 can control 8 with the added benefit of lowering the current once energized. The DRV8803 is simpler to operate. The DRV8860 requires some additional firmware to program the features.

  • 0 in reply to Chris van der Aar
    TI__Expert 4940 points

    Hi Chris,

    Main differences DRV103/DRV110:

    1. DRV110 solenoid current  is not internally limited, limited by the external FET

    2. DRV110 max freq is 27kHz vs 100kHz for DRV103

    3.DRV110 has independent Ipeak/Ihold control, lower power dissipation during Ipeak due to <100% duty cycle

    4. DRV110 duty cycle is internally adjusted

    5. DRV110 has higher Vin range due input Zener block

    6. DRV110 has undervoltage detection

    Regarding your second question, DRV120 is a good candidate if max current is ~200mA. Device is similar to DRV110 with internal FET

    Regards,

    Costin

  • 0 in reply to Rick Duncan
    Intellectual 570 points

    In relation to this DRV8803. We want to control 3 valves (+24V/2W and 3.3W inrush) and a solenoid (+24V/7W). In fact we could use the DRV8803 for this. However we would like to have some diagnostics so we can check if there is a load present at the output? Are there similar devices with this kind of diagnostics features?