CPAP Machines

CPAP Machine Solutions from Texas Instruments

Reference Designs


CPAP or Continuous Positive Airway Pressure is a method of respiratory ventilation used mainly for the treatments of sleep apnea at home. During sleep, the muscles tend to naturally relax causing the upper airway to become narrow. This reduces the amount of oxygen in the blood and causes arousal from sleep.

Pressure sensors play an important role for respiration equipment by converting physical values such as airway pressure and flow into a differential signal. The air and flow sensors generate signals to help the microprocessor regulate the motor to adjust/maintain the desired pressure as the person inhales or exhales. Often, the sensors are very cost-effective with large offset and offset drift causing the signals to be off scale, temperature variant and non-linear. Amplifiers with low offset voltage and drift over time and temperature are ideal for signal conditioning.

The actual controlling of the DC Motor can be done by monitoring at least two of the three current phases and the DC bus voltage feeding the motor drive bridge. For the phase currents, two approaches can be used: high-side or low-side. Direct phase measurement or high side, requires high speed difference amplifiers or current shunt monitors and is generally more accurate. The low-side approach measures near the half bridge ground connection and uses more simple amplifiers which can be less costly but also less precise. The DC Motor is driven by discrete FETs. TI's DRV family offers an integrated driver and bridge with thermal protection that is smaller, more precise and much more efficient that is highly recommended.

The microprocessor performs multiple operations including sampling the pressure signals and computing a desired airway pressure and flow level to communicate with the motor. To achieve these operations efficiently and in real-time, a high-speed, low-power, highly-integrated microprocessor should be used. A high-quality DSP can be used for such applications and will also provide the patient with an ultra quiet operation.

Application notes & user guides

Application Notes (4)

Title Abstract Type Size (KB) Date Views
PDF 240 KB 24 Jul 2015 1792
HTM 9 KB 28 Feb 2013 5974
HTM 8 KB 08 Jun 2009 487
HTM 8 KB 20 Jan 1999 646

Selection & solution guides

Selection Guides (2)

Title Abstract Type Size (KB) Date Views
PDF 9.09 MB 02 May 2013 3476
PDF 11.49 MB 05 Aug 2010 705

Solution Guides (1)

Title Abstract Type Size (KB) Date Views
PDF 2.3 MB 20 Nov 2015 37269

Tools & Software

Name Part # Company Software/Tool Type
DRV10983 Three-Phase Brushless Motor Driver Evaluation Module DRV10983EVM Texas Instruments Evaluation Modules & Boards
HDC1080EVM Low Power Humidity and Temperature Sensor Evaluation Module HDC1080EVM Texas Instruments Evaluation Modules & Boards
PGA900 Evaluation Module PGA900EVM Texas Instruments Evaluation Modules & Boards

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