PMRO-Dx, an environmental sensor measurement chip based on DDCM core technology

According to MEMS Consulting, recently, Prime Semi, a sensor semiconductor solution provider, announced the launch of PMRO-Dx, an environmental sensor measurement chip based on DDCM core technology. Based on the original differential delay chain array technology and making full use of the global team's nearly 30 years of high-performance analog and mixed-signal experience, PMRO-Dx provides the industry with the first highly integrated, high-performance, and cost-controlled single-chip solution.

PMRO-D1 integrates all functional components required for particle, gas or proximity measurement, including the drive of optical signal (LD or LED), transimpedance for converting echo (output as current through PD) into voltage and amplifying, two-stage programmable gain, analog-to-digital conversion, 16-bit microprocessor, and constant power, fan (or micropump) drive circuit, etc. Users only need to adapt the housing, optical transceiver (including lens) and fan on the basis of reasonable aerodynamic design to complete the complete hardware part of the particle sensor. The functional block diagram of PMRO-D1 is as follows.

Functional Block Diagram

The application block diagram of typical particulate matter (PM1, PM2.5, PM10) is as follows.

Typical particle application block diagram (external host is not required)

PMRO-D1 integrates the basic control unit for particle measurement and supports the following three operating modes:

- Single measurement;

- reference measurements;

- Continuous mode measurement.

Reference measurement is mainly used for benchmark measurement of PD dark current and amplifier offset. It can be performed by setting register bits without turning on LD or LED. The integrated analog front end has extremely high consistency and stability, which greatly reduces the calibration time and economic cost required for traditional separate solutions.

In continuous mode, the particle distribution histogram can be automatically measured and calculated by configuration. The measurement and calculation time is defined in the register and can be selected as 400ms or 100ms.

The continuous mode measurement process can be performed in sleep mode. This allows the measurement process to be performed only through UART requests without the need for software to run all the time. This is shown in the figure below.

Continuous mode measurement

In addition, the PMRO-D1's continuous measurement capability in sleep mode can significantly reduce program space, lower current consumption, and improve anti-interference performance.

In summary, compared with the traditional separate PM2.5 sensor measurement solution, PMRO-D1 has at least the following advantages:

- Single-chip hardware system, highly integrated;

- High performance of analog front end (transimpedance, programmable gain, mixed signal);

- Self-calibration and low power consumption supported by underlying logic;

- High flexibility in supporting LD and LED light sources;

- Further optimization of BOM and calibration time cost;

- Easy to use, fast time to market.

The package of PMRO-D1 is QFN24. The development tools currently available include the following:

- Chip sample: PMRO-D1;

- Evaluation kit: PMRO-D1-EK;

- JTAG programmer: PMRO-PROG.

Based on PMRO-D1, Palit Semiconductor will also establish a complete product matrix as soon as possible to support non-dispersive infrared (NDIR) gas sensors, including methane (CH4), carbon dioxide (CO2) and carbon monoxide (CO).