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Infineon has introduced the PSoC 4100T Plus , a new 32-bit microcontroller that fuses system control with ultra-low-power capacitive sensing. Traditional touch sensing solutions often rely on external components or consume excessive energy during polling cycles.
PSoC 4100T Plus.
By embedding advanced analog signal processing and capacitive digitization into the microcontroller core, Infineon hopes the new solution will benefit embedded systems that require touch and gesture detection without compromising power budgets.
Capacitive Sensing for Power-Conscious Embedded Designs
The PSoC 4100T Plus (datasheet linked) is a 32-bit microcontroller platform built around a 48-MHz Arm Cortex-M0 core. To support this compute, the device provides up to 128 KB of flash with a tightly coupled read accelerator that achieves 85% of single-cycle SRAM access speeds. It also offers 32 KB of SRAM and 8 KB of supervisory ROM for boot and configuration routines.
The integrated power system supports a voltage input range from 1.71 V to 5.5 V and operates across three power modes (active, sleep, and deep sleep)—switching clocks and subsystems to minimize consumption.
With a focus on capacitive sensing in power-constrained embedded systems, the MCU integrates Infineon’s fifth-generation Capsense MSCLP block, which uses a ratio-metric analog architecture to deliver a high signal-to-noise ratio (>5:1) and advanced proximity sensing. The MSCLP subsystem autonomously scans channels and detects touch during deep sleep mode at just 8 µA, and tracks active touches with a typical draw of 300 µA.
Block diagram of the PSOC 4100T Plus.
Peripheral subsystems include six TCPWM blocks with quadrature decoding and dead-band control and a 12-bit, 1-Msps SAR ADC with an eight-channel sequencer. It also includes smart I/O fabric to allow Boolean logic functions on GPIO signals. The system also includes two runtime-configurable SCBs supporting I2C, SPI, or UART and three dedicated UARTs with eight-deep FIFOs.
The clocking architecture includes a ±1% internal main oscillator (IMO) adjustable from 24 MHz to 48 MHz, a 40-kHz internal low-power oscillator (ILO), and a 32-kHz watch crystal oscillator. The MCU enables up to 53 GPIOs across multiple package options and is supported by the ModusToolbox ecosystem, which provides BSPs, middleware, and industry-standard development tools.
Infineon Leverages Capsense Tech
Infineon’s Capsense technology is a capacitive sensing system built into PSoC microcontrollers to support high-resolution proximity and touch detection with low power operation. It uses both self-capacitance and mutual-capacitance techniques. Self-capacitance is based on the change in capacitance between a sensor pad and ground, while mutual capacitance is based on the variation between a transmitter and receiver electrode pair. The system measures changes in femtofarad-level capacitance to detect the approach or presence of a conductive object. These changes are digitized by a capacitance-to-digital converter and processed as “raw counts,” which the firmware compares against a baseline to determine activation events.
Electric field lines coupling to a human finger.
The Capsense subsystem incorporates a hardware-based sigma-delta modulator (CSD) and advanced analog front-end filtering, integrated into a multi-scan converter low-power (MSCLP) architecture. This architecture enables always-on capacitive sensing while consuming less than 8 µA in deep sleep mode. It also supports autonomous wake-up on touch without waking the CPU. Capsense achieves a signal-to-noise ratio greater than 5:1 by using dynamic baseline tracking and digital filtering techniques such as IIR and CIC2 filters.
To support directional detection and large proximity ranges, the system allows designers to implement loop or trace sensors with optimized shield electrode placement. Shielding minimizes parasitic capacitance and environmental coupling.
Expanding Touch in Embedded Applications
With wearable devices requiring both longer battery lives and touch-based user interfaces, an integrated solution like the PSoC 4100T Plus may be a powerful new tool for engineers. The PSoC 4100T Plus is now available through Infineon and authorized distribution channels.
