STEVAL-IHT001V1 STMicroelectronics, STEVAL-IHT001V1 Datasheet - Page 9

• Manufacturer Part Number: STEVAL-IHT001V1
• Description: EVAL BOARD THERMO CONTROL REFRIG
• Manufacturer: STMicroelectronics

Specifications of STEVAL-IHT001V1

• Design Resources: STEVAL-IHT001V1 Gerber Files STEVAL-IHT001V1 Schematic STEVAL-IHT001V1 Bill of Materials
• Main Purpose: Reference Design, ARM7 Thermostat for Fridge or Freezer
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: ACS102-6, ACS110, ACST6, ST7LITE39F2
• Primary Attributes: Compressor, Defrost & Light Controls
• Secondary Attributes: Graphical User Interface
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-5514

UM0277
2.3.2
2.3.3
ST7LITE39F2 microcontroller
The MCU used in the thermostat kit is the ST7LITE39F2. It belongs to the ST7LITE39F2
MCU family. It embeds a large number of features at the minimum cost. The peripheral
hardware requirements are then reduced to the minimum:
●
●
In case of MCU firmware change, four options have to be set:
●
●
●
●
Capacitive power supply
To reduce the board price as much as possible, a capacitive power supply is used on the
board. The maximum average current sunk by the board is about 30mA for 4ms gate current
pulse widths (see
for the board to work correctly under typical application conditions (nominal capacitor value,
230V RMS line voltage).
Table 2.
For higher or lower currents, the C3 capacitor can be changed.
allowed average current versus the different C3 capacitor values for typical application
conditions (nominal capacitor value, 230 V
(nominal C3 capacitor value -10%, 198 V
For more information about the design of the capacitive power supply please refer to
Application Note AN1476.
MCU
LEDs
Gate average
current necessary
to control AC
switches
Others (Push
Button, NTC
supply, Buzzer)
Total
No crystal oscillator or external resonator is used. Indeed, the internal RC-oscillator of
the ST7LITE39F2 is used to generate the clock.
No external RESET circuit is used, due to the internal circuit of the ST7LITE39F2.
Software watchdog activation
RC oscillator selection
PLL disabled
Low Voltage Detection selection
Devices
Maximum average current sunk by the board
Table
2.5mA
2.7mA
21mA
4.3mA
30.5mA
Average current
consumption
2). In this case, a 1µF C3 capacitor value should be used in order
Maximum supply current in Run Mode.
LEDs switch ON/OFF alternatively on each AC mains
polarity in order to reduce the current consumption.
R
Switches Q1 (Compressor) and Q2 (Defrost) cannot be
switched ON at the same time. The gate average current is
only defined according to the Q2 (Defrost) and Q3 (Light
Bulb) gate current.
V
R
V
R
(I
f
V
CPU
Buzzer supply current
DD_Max
DD_Max
9
5
15
F
= R
= 390Ω±5% and 4ms gate currents pulses widths
RMS
= 1.6V @ I
= 200Ω±5%
RMS
= 1MHz and V
10
line voltage), for a 50Hz mains frequency.
= 5.5V, R
= 5.5V, R
= R
line voltage) and worst application case
11
F
= 750Ohms±1%
= 4mA, V
DSON_MCU
NTC
= 4mA)
DD
@0°C = 16Ω, R
= 5.5V
Comments
DD_Max
Table 3
= 25Ω, R
Functional description
= 5.5V and
lists the maximum
14
4
= 130Ω±5%,
= 10kΩ±5% and
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