What is XENSIV™ PAS CO2 sensor – Battery Powered Demo Board? - KBA234294
Community Translation: XENSIV PAS CO2センサー－バッテリ駆動のデモボードとは何ですか？ - KBA234294
1. General Idea
The “XENSIV™ PAS CO2 sensor – Battery-Powered Demo Board” is a fully functional board that demonstrates the potential of Infineon’s PAS sensor and the DPS368 Pressure sensor. This hardware is based on an ESP32-WROOM and a custom-made shield. The demo board is battery-powered and charged up with a single USB connection.
2. Characteristics of the setup
2.1 Demo board
- Battery charger controller
- Buck-Boost converter for stable 3.3 V supply
- +12 V Step-Up converter for PAS sensor
- 1x XENSIV™ PAS CO2 sensor
- 1x Pressure/Temperature sensor (DPS368)
- Battery voltage monitoring
2.2 Block diagram
Figure 1 Block diagram of XENSIV™ PAS CO2 sensor Battery-Powered Demo Board
3. Photos from the setup
Figure 2 Shield view with PAS sensor (TOP) and Pressure sensor (Bottom)
3.2 PCB dimensions
- 55 mm x 28 mm
4 Demo board detailed description
4.1 Battery charger
The battery charger circuit is based on the BQ24166 IC from Texas Instruments. This circuit is a 2.5 A, dual-input, single-cell switch mode Li-Ion battery charger with Power Path Management.
Figure 3 Schematic diagram of Battery charger
Figure 4 Shield view with Battery charger
4.2 Buck-Boost converter
In order to have stable 3.3 V, no matter if the battery voltage is greater or smaller than 3.3 V, the TPS63070 (Texas Instruments) IC as used. This circuit is a 2 V to 16 V Buck-Boost converters with 3.6 A Switch Current.
Figure 5 Schematic diagram of Buck-Boost converter
Figure 6 Shield view with Buck-Boost converter
4.3 Step-Up converter
The Step-Up converter is used to generate the 12 V needed by the PAS Circuit.
This circuit is based on the LT3580 from Analog Devices (Linear Technologies) and this is a Boost/Inverting DC/DC converter with 2 A switch, soft-start, and synchronization.
Figure 7 Schematic diagram of Step-Up converter
Figure 8 Shield view with Step-Up converter
4.4 Battery voltage monitoring
In order to check the battery voltage, the TPS3803-01 (Texas Instruments) IC was used. This IC is a simple voltage detector.
The circuit is done to detect a battery voltage lower than 3.4 V and trigger a RESET line that is read by the uC.
Figure 9 Schematic diagram of Battery voltage monitoring
Figure 10 Shield view of Battery voltage monitoring
4.5 Indicative LEDs
The shield incorporates 4 different LEDs.
- Battery charging (Green LED)
- Power good indicator (External power) (Green LED)
- Human interface (Blue LED)
- Low battery (Red LED)
4.6 External battery
A rechargeable battery, CC/CV, 3.7 V, Lithium Polymer, 1.4 Ah is used in this project.
Figure 11 External battery
5 How To
For connecting the demo board setup, please follow the next steps:
- Plug the ESP32 board together with the shield as shown in the following picture:
- The antenna of the ESP32 gets on the opposite side of the PAS Sensor.
- Do not rotate the PCB 180°.
Figure 12 Orientation of the ESP-WROOM-32 board
2. Connect the battery to the demo board as shown in the following picture:
- White: NTC sensor
- Black: GND
- Red: VDD
Figure 13 Connections with the external battery
6 Getting started
To communicate with the sensor, check out the following GitHub link and program the relevant registers to get started with the kit.
C++ library for Infineon's XENSIV™ PAS CO2 sensor miniaturized sensor -
The link provides more information on supported frameworks and reference sensor board.
7 Relevant links
Knowledge Base Articles