ST STEVAL-IHT001V1, Руководство пользователя

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Functional description UM0277
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Figure 4. Defrost activation principle
Note: The ACS110-7SB2 switch can drive a fan instead of a defrost resistor in order to move the
air around the coils inside the refrigerator. This fan helps to increase the cooling efficiency,
and also speeds up the defrost process.
2.3 Hardware features
2.3.1 ACS and ACST devices
The STEVAL-IHT001V1 board embeds one ACS102-6TA, one ACS110-7SB2 and one
ACST6-7ST switches. The datasheet of these devices can be found in our web site (go to
www.st.com/thyristors).
Table 1 sums up the main differences between ACS and ACST
switches and traditional TRIACs.
Sum of Compressor ON times > DEFROST
ACTIVATION DELAY
Ö Defrost enabled
TEMP1
TEMP2
DEFROST
Compressor
Evaporator temperature evolution
∆
t
t
t
t
TEMP1
TEMP2
DEFROST
Compressor
Evaporator temperature evolution
∆
t
t
t
t
Evaporator temperature > TEMP1
Ö Defrost turn-on
After DEFROST DURATION (
∆
t)
Ö Defrost turn-off
Ö Compressor turn-on
Table 1. Differences between ACS/ACST and TRIACs
Device 1A TRIAC ACS102 1A TRIAC ACS110 6A TRIAC ACST6
Igt (mA) 5 5 10 10 10 10
Overvoltage Protection No Yes No Yes No Yes
(dV/dt) 20 V/µs 300 V/µs 50 V/µs 500 V/µs 100 V/µs 200 V/µs
(dI/dt) at turn-on 10 A/µs 20 A/µs 20 A/µs 50 A/µs 20 A/µs 100 A/µs