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Cost optimized method to generate 12V and 3.3V from 5V for XENSIV™ PAS CO2 sensor - KBA234207

Cost optimized method to generate 12V and 3.3V from 5V for XENSIV™ PAS CO2 sensor - KBA234207

ArunKumarChoul
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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). 

ArunKumarChoul_0-1636541689242.png

 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.

ArunKumarChoul_1-1636541807444.png

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 - 4.7k 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:

ArunKumarChoul_2-1636542148442.png

Figure 3: Boost converter schematic (5V to 12V)

The schematic for the power supply (buck converter) is as follows:

ArunKumarChoul_3-1636542217034.png

Figure 4: Power supply for MCU (5V to 3.3V)

 

 

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