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INA233: Asking for INA233 response time

SHH
Mastermind 32206 points
Part Number: INA233

Hi Team,

Customer is designing INA233 and the setting are as below.

Rshunt is10mohm.

 

0xD4 => 0x0200 (1mA/step)

0x4A => 0x2710

0xD0 => 0x4825

0xD2 => 0x00FB

 https://e2e.ti.com/support/amplifiers/f/14/t/877650

Based on previous post suggestions, 0xD0 register change from 0x4827 to 0x4825. However the response time on INA233 is over 100ms. Would you please provide comment how to shorten the response time on INA233 on Exp1? And how customer can make the response more consistent?

 

Exp1:

Customer capture the waveform as below.

CH0:SCL (MCU polling INA233 every 10ms)

CH1: SDA (MCU polling INA233 every 10ms)

CH2: MCU GPIO (if the I2C read back value change, it will pull low)

CH3: MCU GPIO (if the external dummy resistor load plug in, MCU will detect the plug event)

 

From CH3 dummy load plugging to CH2 pull low, it took around 133ms. Customer expect the read back time from INA233 should be less than 30ms.

 

Exp2:

Customer also do 6 times capture here by e-load and use scope to capture the waveform

CH1: current monitor by current probe.

CH2: the MCU GPIO event will goes low once the INA233 read back value is changed. (MCU code is changing to change to GPIO from high to low only)

The question here is that the time duration between six. the variation is from 113~222ms.

 

BR,

SHH

  • 0
    TI__Mastermind 34250 points

    Hi SHH,

    The variation observed depends on how the INA233 is instructed to do the measurement.

    Currently the averaging number of samples equals to 128 and conversion time equals to 1.1mS. This works out to be 141mS of effective conversion time. Therefore the variation observed should be anywhere between 0mS and 141mS. And the “system response time” equals to 2X effective conversion time or 282mS (due to asynchronous nature between external load and INA233 operation). Apply both criteria to the measurements, and you’ll see the device is performing within spec.

    Based on the 6 scope shots provided, the largest variation among them is 222mS-113mS=109mS, which is less than 141mS. In addition all “response time” is within 282mS.

    To reduce the variation, and to shorten the overall “response time”, please set 0xD0 => 0x4025, customer should observe dramatic improvement.

    Regards, Guang