11

AFE3010

www.ti.com

SBFS042 – JUNE 2020

Product Folder Links: AFE3010

Submit Documentation Feedback

Copyright © 2020, Texas Instruments Incorporated

7.3.7 Self-Test Function

The AFE3010 performs two different types of self-tests: periodic self-test and continuous self-test.

7.3.7.1 Periodic Self-Test

At system power up, the self-test starts after 60 cycles of power line signal, and retests within 60 cycles if the first

self-test fails. Five consecutive self-test fails drive the SCR and assert the ALARM signal blinking at 1-second

intervals (for 60-Hz systems). After the first self-test pass, the device fires ALARM for 250-ms period to indicate

the successful pass of the first self-test. During normal operating conditions, the self-test repeats every 180

cycles. Figure 10 shows the periodic self-test sequences and decision blocks. The device requires one cycle

from the AC power line to complete the periodic self-tests listed below:

1. Ground Fault Test: the AFE3010 generates a fault current through the FT pin. The device reads a test pass if

the AFE3010 detects the fault current through the transformer. If the fault current is not detected, the device

reads a test fail. This fail event triggers another self-test within next 60 cycles. After five consecutive fails, the

AFE3010 fires the SCR and sets the ALARM blinking at 1-s intervals (for 60-Hz systems). The ground fault

test covers the integrity check of the transformer, fault current generator components, feedback resistors,

and the AFE3010 fault detection circuits.

2. SCR Integrity Test: The AFE3010 performs SCR integrity test after completing the ground fault test. The

device induces a SCR anode signal transition with the help of SCR_TST pin. If the SCR anode signal low

transition is not detected, the AFE3010 reads a test fail. This fail event triggers another self-test within next

60 cycles. After five consecutive fails it fires the SCR and sets ALARM blinking at 1-s intervals (for 60-Hz

systems).

7.3.7.2 Continuous Self-Test

The AFE3010 performs the following continuous mode self-tests. If any of these tests fail, the device does not

wait to perform another self-test. Rather, the AFE3010 immediately fires the SCR and sets the ALARM blinking

as 1-s intervals (for 60-Hz systems).

1. Open Solenoid Test: The AFE3010 checks for transition of AC line signal at the PH and SCR_TST pins. If

the device does not detect a transition of the line signal at PH or SCR_TST pins for approximately 100 ms,

then the device reads a self-test fail.

2. Diode Bridge Test: if a diode is shorted in the diode bridge rectifier, the device is able to detect the variation

in supply current from the diode bridge. This detection is considered a self-test fail, and the AFE3010 fires

the SCR and sets the ALARM blinking at 1-s intervals (for 60-Hz systems).

3. Amplifier Short/ Open: The device monitors for sustained fault current conditions, even after the fault current

has been detected and SCR has fired. The primary purpose of this self-test is to detect a single-point failure

with the amplifier signal pins and associated components. If a failure is detected, the device fires SCR one

more time and LED starts blinking. In the event the load switch doesn't open after SCR is fired, this self-test

recognizes a failure and starts the LED blinking.