DRV421_15 Datasheet, PDF (26/44 Pages) Texas Instruments – DRV421 Integrated Magnetic Fluxgate Sensor for Closed-Loop Current Sensing

DRV421
SBOS704A – MAY 2015 – REVISED JULY 2015
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7.3.10 Error Flag
The DRV421 features an error output (ER pin) that is activated under multiple conditions. The error flag is active
when the output voltage is not proportional to the primary current; during a power fail or brownout; during a
demagnetization cycle; or when the magnetic field on the fluxgate is greater than 1.7 mT (saturation of the
fluxgate). Saturation is usually caused by either the consequence of an overload current (see the Overload
Detection and Control section) or due to a power up in the presence of a primary current (see the Search
Function section).
The error flag resets as soon as the error condition is no longer present and the circuit has returned to normal
operation. The error flag is an open-drain logic output. Connect the error flag to the overrange flag for a wired-
OR; for proper operation, use an external pull-up resistor. The following conditions result in error flag activation
(ER asserts low):
1. For 80 µs after power-up
2. If a supply-voltage brownout condition (V_DD < 2.4 V) lasts for more than 20 µs
3. If the sensed magnetic field is > 1.7 mT because:
– Overload control is active
– Search function is active
4. Demagnetization cycle is active (see the Magnetic Core Demagnetization section)
7.4 Device Functional Modes
The DRV421 has a single functional mode and is operational when the power-supply voltage is greater than 3 V.
The maximum power supply voltage for the DRV421 is 5.5 V.
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