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CN-122029739-A - Class D amplifier device for haptic applications

CN122029739ACN 122029739 ACN122029739 ACN 122029739ACN-122029739-A

Abstract

The input signal may be converted to a first PWM signal and a second PWM signal at the PWM controller circuit. The first PWM signal and the second signal output may drive a driver circuit. The driver circuit may receive the high voltage supply from a boost converter or other power circuit. The driver circuit may include a high-side device and a low-side device. The output of the driver circuit may drive a filter circuit comprising a filter capacitor, an inductor, and a haptic actuator. The haptic actuator may produce a desired haptic response at the haptic actuator.

Inventors

  • R. Kostakai

Assignees

  • 微芯片技术股份有限公司

Dates

Publication Date
20260512
Application Date
20240412
Priority Date
20240410

Claims (16)

  1. 1. A class D amplifier device, the class D amplifier device comprising: a PWM controller circuit for receiving an input signal and generating a first PWM signal and a second PWM signal based on the input signal, the first PWM signal comprising a fixed frequency PWM signal and the second PWM signal being a non-overlapping version of the first PWM signal; A first plate of a first coupling capacitor, the first plate of the first coupling capacitor coupled to receive the first PWM signal; a first plate of a second coupling capacitor, the first plate of the second coupling capacitor coupled to receive the second PWM signal; A driver circuit including a high-side device coupled to the second plate of the first coupling capacitor and a low-side device coupled to the second plate of the second coupling capacitor, the driver circuit for driving the output node, and A filter circuit coupled to the output node, the filter circuit comprising: a filter capacitor; Inductor and A haptic actuator; Wherein the filter capacitor includes a first plate coupled to the output node and a second plate coupled to a common node, the inductor includes a first node coupled to the output node and a second node coupled to the first node of the haptic actuator, and the second node of the haptic actuator is coupled to the common node.
  2. 2. The device of claim 1, the high-side device comprising a metal oxide semiconductor field effect device (MOSFET).
  3. 3. The device of any of claims 1-2, the low-side device comprising a metal oxide semiconductor field effect device (MOSFET).
  4. 4. A device according to any one of claims 1 to 3, the high side device being for receiving a supply voltage from a boost converter for converting a battery voltage to a high voltage supply, the high voltage supply being greater than or equal to 10 volts.
  5. 5. The device of any of claims 1-4, the input signal comprising a burst sinusoidal signal, the burst sinusoidal signal being based on a desired haptic response.
  6. 6. The device of any one of claims 1 to 5, the haptic actuator comprising a piezoelectric actuator.
  7. 7. A system, the system comprising: A microcontroller for generating an input signal for generating a haptic response at a haptic actuator; A PWM controller circuit for receiving the input signal and generating a first PWM signal and a second PWM signal based on the input signal, the first PWM signal comprising a fixed frequency PWM signal and the second PWM signal being a non-overlapping version of the first PWM signal; A coupling circuit for coupling the first and second PWM signals to a driver circuit, the driver circuit including a high-side device and a low-side device, and the driver circuit for driving an output node, an A filter circuit communicatively coupled to the output node, the filter circuit for filtering the output node.
  8. 8. The system of claim 7, the coupling circuit comprising a first coupling capacitor coupled between the first PWM signal and the high-side device, and comprising a second coupling capacitor coupled between the second PWM signal and the low-side device.
  9. 9. The system of any of claims 7 to 8, the input signal comprising a burst sinusoidal signal, the burst sinusoidal signal being based on a desired haptic response.
  10. 10. The system of any of claims 7 to 9, the haptic actuator comprising a piezoelectric actuator.
  11. 11. The system of any of claims 7 to 10, the driver circuit to receive a supply voltage from a boost converter.
  12. 12. A method, the method comprising: receiving an input signal for generating a haptic response at a haptic actuator; Converting the input signal into a first PWM signal and a second PWM signal, the first PWM signal comprising a fixed frequency PWM signal and the second PWM signal being an inverted and non-overlapping version of the first PWM signal; coupling the first PWM signal to a first coupling capacitor and the second PWM signal to a second coupling capacitor; driving a driver circuit using outputs of the first coupling capacitor and the second coupling capacitor, and The output of the driver circuit is filtered with a filter circuit.
  13. 13. The method of claim 12, the input signal comprising a burst sinusoidal signal, the burst sinusoidal signal being based on a desired haptic response.
  14. 14. The method of any of claims 12 to 13, the driver circuit comprising a high-side device and a low-side device.
  15. 15. The method of claim 14, the high-side device to receive a supply voltage from a boost converter.
  16. 16. The method of any of claims 12-15, the haptic actuator comprising a piezoelectric actuator.

Description

Class D amplifier device for haptic applications Priority The present application claims priority from commonly owned U.S. provisional patent application No. 63/543,859 filed on 10/2023, the entire contents of which are hereby incorporated by reference for all purposes. Technical Field The present disclosure relates to a class D amplifier for haptic applications. Background The haptic driver may drive the haptic actuator with an electrical signal to produce a mechanical response. In haptic applications, signals applying different voltages and frequencies may cause different mechanical responses. These different mechanical responses may be perceived by the user as button presses, switch toggles, or other physical responses. The use of haptic drives and haptic actuators to generate a physical response may be referred to as haptic technology. Haptic technology may be utilized to generate a vibratory alert or other physical response in a mobile device, including but not limited to a cellular telephone or game controller. Haptic technology may be utilized in automotive applications as part of a steering wheel or console interface on a touch screen. In battery-powered applications with haptic actuators having large capacitive loads, system power consumption becomes an important factor. For example, driving arbitrary modes on a large capacitance haptic actuator from a Li-ion battery at high voltage becomes a challenge. Portable haptic applications with large capacitive actuators having capacitances exceeding 1uF require significant drive power at high voltage operation. The haptic actuator may require a driving voltage exceeding 100V. Boosting such a drive voltage from a 4V battery input after taking into account the power supply losses, which is typical, would result in very low efficiency and render the method impractical. There is a need for a device that can drive a haptic actuator with high voltage with improved efficiency. Disclosure of Invention Examples herein implement systems and methods for driving a haptic actuator with a class D amplifier. According to one aspect, a class D amplifier device includes a PWM controller circuit. The PWM controller circuit receives an input signal and generates a first PWM signal and a second PWM signal based on the input signal. The first PWM signal may be a fixed frequency PWM signal and the second PWM signal may be a non-overlapping version of the first PWM signal. A first plate of the first coupling capacitor may be coupled to receive the first PWM signal and a first plate of the second coupling capacitor may be coupled to receive the second PWM signal. The driver circuit may include a high-side device coupled to the second plate of the first coupling capacitor and a low-side device coupled to the second plate of the second coupling capacitor. The driver circuit may drive the output node. A filter circuit may be coupled to the output node, the filter circuit including a filter capacitor, an inductor, and a haptic actuator. The filter capacitor includes a first plate coupled to the output node and a second plate coupled to a common node. The inductor includes a first node coupled to the output node and a second node coupled to the first node of the haptic actuator. The second node of the haptic actuator may be coupled to a common node. According to one aspect, a system includes a microcontroller for generating an input signal for generating a haptic response at a haptic actuator. The system may include a PWM controller circuit. The PWM controller circuit may receive the input signal and may generate a first PWM signal and a second PWM signal based on the input signal. The first PWM signal may be a fixed frequency PWM signal and the second PWM signal may be a non-overlapping version of the first PWM signal. The coupling circuit may couple the first PWM signal and the second PWM signal to a driver circuit. The driver circuit may include a high-side device and a low-side device. The driver circuit may drive the output node. A filter circuit may be coupled to the output node, the filter circuit for filtering the output node. According to one aspect, a method includes receiving an input signal for generating a haptic response at a haptic actuator, converting the input signal to a first PWM signal and a second PWM signal, the first PWM signal including a fixed frequency PWM signal and the second PWM signal being an inverted and non-overlapping version of the first PWM signal, coupling the first PWM signal to a first coupling capacitor and the second PWM signal to a second coupling capacitor, driving a driver circuit with outputs of the first coupling capacitor and the second coupling capacitor, and filtering the output of the driver circuit with a filter circuit. Drawings Fig. 1 illustrates one of various examples of a class D amplifier device for haptic applications. Fig. 2 illustrates one example among various examples of timing diagrams of the first PWM signal and the seco