Board Immunity Performances; Hardware And Software Features To Increase Immunity; Software Features; Surge Tests Results - STMicroelectronics STEVAL-IHT005V2 User Manual

Board immunity performances

6 Board immunity performances
6.1

Hardware and software features to increase immunity

Software features

Software features to improve board immunity are

Filtering procedure for button and potentiometer control

Software watchdog
Hardware features to improve board immunity are

Input varistor

ACS-ACST technology and Transil™ as an option for T1635H-6T

47 nF input X2 capacitor
 Noise suppressor circuits are implemented (10 nF X2 capacitor and 75  resistor)

R-C-R filter on gate implemented (RG/2, 10 nF, RG/2)
Layout golden rules for immunity improvement

Power tracks far from signal tracks

V
SS

Noise suppressor and R-C-R gate filter close to AC switches and Triacs

Input MCU pins have implemented filter capacitor 10 nF

Any branch in the V
6.2

Surge tests results

Standard IEC 61000-4-5 tests were performed with surge level of 2 kV, which is required for
home appliances. Mains voltage used for the tests was 230 Vrms/50 Hz.
The ACST16 device is protected against overvoltage spikes up to 2 kV with implemented
crowbar technology. See the ACST16 datasheet for further details.
ACS devices are protected against overvoltage spikes up to 2 kV with implemented crowbar
technology. See the ACS108-8S datasheet for further details.
The Z01 Triac is protected thanks to the noise suppressor circuit and high impedance of the
load (refer to the AN437 application note for snubber design).
The T1635H is protected with Transil P6KE400CA. This is a different implementation of the
crowbar technology. The purpose here is to propose overvoltage protection with a crowbar
technology. This method presents the advantage of not aging contrary to the varistor
technology.
14/27
map
map has implemented a capacitor to decrease the V
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DocID024503 Rev 1
UM1631
variation
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