Summary
The SSP8011A-A is a low-cost, low-power single-channel capacitive touch sensing IC.
Built-in voltage regulator circuit, few peripheral components, only a few components can achieve touch sensing.
Provides 2 output modes, high/low output optional.
Reset after a maximum of 9S.
The sensitivity of the touch-sensitive keys can be adjusted as needed by adjusting the external resistance and capacitance.
Product characteristics
- Single channel capacitive touch sensing button；
- Working voltage: 2.2V~5.5V;
- Ultra-low power consumption: 1.3μA @VDD=3V;
- The longest response time: Low power mode < 140mS; Normal mode is less than 70ms;
- The sensitivity of the keys can be freely adjusted by external resistance and capacitance;
- Switch mode and button mode, output state high or low level can be selected;
- The maximum duration of continuous pressing is 9S to enter the initial power-on mode.
Pins and parameters
Typical Applications
Application circuits
Application in helmet wearing sensing
The customer is developing a helmet module with wearing detection, and the specific requirements are quite strict:
- The capacitance of the human body can still be sensed at a distance of 1 cm from the hair.
- ABCD 4-point detection, high cost requirement, convenient to add detection points.
- Ultra-low power consumption for continuous operation, one CR2450 can last for more than 1 year.
Helmet sensing point map
We put the touch chip separately on a small board, use a larger area as the sensing area, plug into the four areas of ABCD, use the three-core wire to lead to the MCU control board, when the human body capacitance is sensed, the corresponding signal pin generates a high level.
SSP8011A-A circuit board
After actual testing, adjusting the C3 value can set the sensing distance to about 1cm, which meets the requirements.
The figure below shows the power consumption of a single SSP8011A-A during continuous monitoring, which is approximately 1.6μA.
Simultaneous detection at ABCD 4 points, with a total power consumption of 10μA. The MCU remains in STOP mode and will only wake up to process data when the IO of the 4 capacitor detection boards changes.
When 3 or more points are triggered, the helmet is considered to be worn.
When the helmet is removed, all capacitor boards will output a low level, which can trigger an alarm,
After measurement, the power consumption of the entire detection module is less than 12μA, and the CR2450 battery is enough to use for one year.
Brief Summary
- The SSP8011A-A chip is used in the helmet wear detection scheme, achieving wear detection within an average of 1.6μA per point.
- The cost has a great advantage over the infrared beam scheme.
- Easy to expand, more convenient to add detection points.
- Adjustable sensing distance, suitable for a variety of head shapes.
- Power consumption is relatively average, there is no impulse current, and it is friendly to lithium batteries.
