Linear Hall sensors such as DRV5055 and TMAG5253 with an analog output are simple to use and are typically used for analog triggers and thumb-sticks in gaming controllers.

These sensors could be powered directly from a battery or from a regulated supply voltage such as 1.8 V or 3.3 V. To power cycle the sensor, the sensor's supply voltage could be turned off and on by the microcontroller, but in many cases it is not possible since that supply voltage might be also powering up other components in the board. In those cases a load switch could be used to power cycle the sensor. To eliminate additional components such as load switches and achieve the desired power efficiency, linear Hall sensors such as TMAG5253 are available with an EN pin, that is used for power cycling. The linear Hall sensors such as TMAG5253 also feature a very fast power on time (< 25 μs) that allows an external ADC to not only sample the signal faster, but also allows it to shutdown quickly to lower the system power consumption. Figure 2-1 below shows a typical diagram where the sensor’s EN pin is being controlled by the microcontroller. The EN pin can be controlled using a Pulse Width Modulated (PWM) signal, enabling the microcontroller to trade off the sampling frequency and power as needed in the system.

Figure 2-2 shows the timing diagram where the sensor is power cycled using the EN pin. The sensor is turned on for active time, t_active, where the sensor provides an output that is proportional to the external magnetic field and turned off for the time, t_shdn to conserve power. Equation 1 shows the average current consumption of the device, where I_CC,ACTIVE refers to the active current during operation and the I_CC,SHDN refers to the shutdown current.

As an example, TMAG5253 has an active current of 2.1 mA during active mode and less than 10 nA during shutdown mode. If the sensor is power cycled with active time of 50 us and shutdown for 100ms, then this results in an average current consumption of 1.06 μA.