Pulse Density Modulation (PDM) is commonly used in the application of LRA (Linear Resonant Actuator) motors to control their vibration intensity and frequency. LRA motors are used for generating haptic feedback in various devices such as smartphones, gaming controllers, and haptic feedback devices.
To apply PDM to an LRA motor, a fixed-frequency high-frequency pulse train is typically used. The density of the pulses determines the vibration intensity, where a higher density of pulses results in stronger vibrations. By dynamically adjusting the number and width of the pulses, different vibration frequencies and intensities can be achieved.
Here’s a general outline of how PDM is applied to an LRA motor:
Driving the LRA Motor: The PDM signal, consisting of the pulse train with controlled density and width, is used to drive the LRA motor. The motor responds to the pulses by generating vibrations corresponding to the PDM signal.
By utilizing PDM, precise control over the vibration intensity and frequency of the LRA motor can be achieved. This allows for customized haptic feedback experiences, enhancing the user’s interaction with the device.
It’s worth noting that the exact implementation details may vary depending on the specific LRA motor and its associated control circuitry. Manufacturers often provide guidelines and specifications on how to apply PDM for their LRA motors, which can help optimize the performance and achieve the desired haptic effects.
In the context of LRA (Linear Resonant Actuator) motors, both Pulse Density Modulation (PDM) and Pulse Width Modulation (PWM) can be used for controlling the motor’s vibration. Here are the differences between PDM and PWM in LRA motor applications:
PWM: PWM control is relatively simpler to implement as it involves generating a fixed-frequency pulse train and adjusting the pulse widths based on the desired vibration intensity. PWM-based control circuits are commonly available and can be easily integrated into motor control systems.
In summary, PDM and PWM offer different approaches to control the vibration intensity of LRA motors. PDM provides higher control precision and potentially better energy efficiency by adjusting pulse density, while PWM offers a simpler implementation but with slightly lower control precision and potentially higher energy consumption. The choice between PDM and PWM depends on the specific requirements of the application and the desired trade-offs between control precision, energy efficiency, and implementation complexity.
No. | Port Name | Polarity | Description |
1 | RSTN | IN | Asynchronous Reset (low active) |
2 | CLK_Audio | IN | Clock |
3 | pdm_ck | IN | Pulse Density Modulate clock rate, If keep pmd_ck = 1, modulate clock = CLK_Audio |
4 | clr | IN | Synchronous reset (high active) |
5 | mute | IN | Output mute, set spk_p/spm_m to low |
6 | pdm_data | IN | Input data |
7 | spk_p | OUT | H-bridge MOS drive input signal |
8 | spk_m | OUT | H-bridge MOS drive input signal |
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