Cost optimized method to generate 12V and 3.3V from 5V for XENSIV™ PAS CO2 sensor - KBA234207
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In most applications that require CO2 sensing, a 12-V power supply is required for the MEMS heater (IR emitter) that is inside the XENSIV™ PAS CO2 sensor. However, embedded applications generally do not incorporate a 12-V supply. Therefore, you need to convert a 5-V supply to 3.3V and 12V for the MCU and MEMS sensor respectively. To achieve this, Infineon offers a Sensor2Go kit, and an adapter board that includes a buck-boost converter to convert a 5-V supply to 3.3V and 12V (see Figure 1).
Figure 1. XENSIV™ PAS CO2 Sensor2Go kit
Connecting XENSIVTM PAS CO2 mini board with the XENSIV™ PAS CO2 Sensor2Go kit
The Sensor2Go kit provides a combination of a motherboard having a power management circuit and a mini board as shown in Figure 2. The Sensor2Go kit is powered via USB; 5V from the USB is stepped down to 3.3V and stepped up to 12V to ensure appropriate input voltage for the XENSIV™ PAS CO2 device.
Figure 2. Connection between Sensor2Go kit and mini board
The Sensor2Go kit has a form factor of 35mm x 23mm and has an input voltage range of 3.3V to 5.5V. The Sensor2Go kit board is inexpensive; the approximate cost of the board is ~1.5$ (see Table 1).
Table 1. Approximate BOM of the Sensor2Go kit board
Part number |
Component description |
Supplier |
Quantity |
Unit. Cost |
Cost |
PCB |
Gultech |
1 |
$0.1600 |
$0.1600 |
|
06033C104JAT2A |
Capacitor - 0603 - 100nF 25V 5% |
AVX |
2 |
$0.0132 |
$0.0264 |
VJ0603A471JXACW1BC |
Capacitor - 0603 - 470pF 50V 5% |
Vishay (VIT) |
1 |
$0.0091 |
$0.0091 |
C2012X7R1E475K125AB |
Capacitor - 0805 4.7µF 25V 10% |
TDK |
2 |
$0.0500 |
$0.1000 |
08053D106KAT2A |
Capacitor - 0805 10µF 25V |
AVX |
1 |
$0.0912 |
$0.0912 |
VLCF5020T-100MR87 |
Coil - 10µH 1.56A 20% |
TDK |
1 |
$0.2000 |
$0.2000 |
CR0603-FX-4701ELF |
Resistor - 0603 - 4.7kΩ 0.1W 1% |
Bourns (BNS) |
1 |
$0.0025 |
$0.0025 |
TLV61046ADBVT |
Output voltage boost converter |
Texas Instruments |
1 |
$0.5645 |
$0.5645 |
TLS202B1MBV33HTSA1 |
Fixed linear voltage post regulator |
Infineon |
1 |
$0.3882 |
$0.3882 |
Total |
$1.5418 |
The schematic of the boost converter is as shown:
Figure 3: Boost converter schematic (5V to 12V)
The schematic for the power supply (buck converter) is as follows:
Figure 4: Power supply for MCU (5V to 3.3V)