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DRV10983-Q1: Massive power reduction required:

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Replies: 4

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Part Number: DRV10983-Q1

We have been using the DRV10983-q1 and the DRV10983-SQ parts for a little over a year now, but we don't like the 10mA Quiescent current.  Ti have some great micro power devices that might be used in place of the 3.3V supply. We are thinking about the TPS62110 or TPS 60370 as we like the idea of operation beyond 125'C.  We have a canbus device to keep operational SN65HVD233 and a small microprocessor, so we only need 1mA @  3.3V .  But we would like to shut-down the DRV10983 into hibernation until we need it, this is about once a month so it will spend most its life sleeping.  What is the best way to operate the DRV10983 without using the inefficient internal power supply, and how much can i reduce the 10ma by?

Thanks in advance for your help.

Victor

  • Hi Victor,

    Thanks for posting your question in E2E.  DRV10983 enters standby mode when the motor is not spinning. In standby mode, the device provides a supply current of 3 mA by running the step-down regulator. Below table in the data sheet explains more on Standby mode.

     

    Just make sure the sleepDis bit in EECtrl register is not set as this prevents the device from entering into Standby mode.

    Regards,

    Vishnu

  • In reply to Vishnu Balaraj:

    Thank you for your help. In temps of hardware should we power with external power regulator and remove inductors, just leave decoupling capacitor on 3.3V,1.8V,5V?

    Regards

    Victor

  • In reply to VICTOR BEST:

    Victor,

    DRV10983 includes a hysteretic step-down voltage regulator that can be operated as either a switching buck regulator using an external inductor or as a linear regulator using an external resistor as seen in below schematic.

      

    Since you need low quiescent current, it is better to operate the regulator in buck mode as the quiescent current in this mode is 3 mA  compared to operating in linear mode which is 9 mA. You can leave the decoupling capacitors as it is. Since you need a 3.3 V regulated output voltage, set the register bit VregSel to 1. 

    Regards,

    Vishnu

  • In reply to Vishnu Balaraj:

    Using DRV10983Q1 EVM dev board and GUI software the following behavior is observed;(with Q part fitted).

     

    1. Apply VBAT with SPEED input logic high -> IC wakes with approx. 10-11mA supply current (note that a valid operating config is stored in the EEPROM and SpdCtrl register set to 0x0000.
    2. Set SPEED pin low                                   -> IC goes to sleep with <<1mA current
    3. Set SPEED pin high from external 3V3     -> IC wakes up with similar 10-11mA current.
    4. Set Speed Control Override                       -> No change to current (note that checking the box on the UI writes 0x8000 to register 0x30 and then reads back the register 6ms later)
    5. Reset Speed Control Override                   -> The current appears to change to about 7-8mA (note that this action writes 0x0000 to register 0x30 and then reads back the register 6ms later)
    6. Set SPEED pin low                                     -> No effect, although this is nominally the same state as step 2.
    7. Power cycle VBAT                                      -> IC wakes as step 1 and repeating steps 2 & 3 have the same effect if tried here.
    8. Enter Speed value of 10 in UI                     -> No change
    9. Set Speed Control Override                        -> Tiny increase in current.
    10. Reset Speed Override                                 -> IC goes to sleep with <<1mA current
    11. Set SPEED pin high from external 3V3      -> IC wakes up with similar 10-11mA current.
    12. Enter Speed value of 8 in UI                       -> No change
    13. Set Speed Control Override                        -> Tiny increase in current.
    14. Reset Speed Override                                  -> No effect

     

    Questions to ask;

     

    -          Does reading the register 0x30 6ms after writing 0x8000 to it break the condition of tEN_SL_SB condition to put the IC to sleep that is defined in Table 1 of section 8.3.5 of the datasheet?

    -          Why would having a value of at least 10 make any difference to trying to sleep the IC when the datasheet states that SpdCtrl[8:0] should be set to zero?

    -          Is there a simple UI program that can be used with the USB2ANY box that would allow a user to define simple strings of I2C writes (e.g. 0xA4 0x80 0x00 0x00 to set the IC to sleep)?