Class D power driver peripheral
AssigneeMicrochip Technology Incorporated
InventorKeith E. Curtis
Life of this patent
Estimating the term…
Abstract
A Class D peripheral is integrated with a microcontroller as a general purpose driver for providing many different Class D power applications such as motor and solenoid control, audio amplification, etc. Use of a simple triangle waveform (saw tooth) oscillator normally used for detecting changes in capacitance values in combination with a voltage comparator provides inexpensive generation of pulse width modulation (PWM) suitable for a wide range of Class D power applications. Selection of either an external audio input or an internal processor controlled analog reference provides for flexible adaptability to any Class D power driver requirement.
Claims21
A class D power driver peripheral, comprising:
- a voltage comparator;
- a differential amplifier having first and second inputs adapted for coupling to a load;
- an operational amplifier having a first input coupled to an output of the differential amplifier and a second input coupled to an analog voltage, wherein an output of the operational amplifier is coupled to a first input of the voltage comparator;
- and
- a closed loop compensation circuit coupled between the first input and the output of the operational amplifier;
- a capacitive sensing module (CSM) having an output coupled to a second input of the voltage comparator and to an external capacitor, wherein the CSM provides a triangle waveform output to the voltage comparator and the external capacitor determines a frequency of the triangle waveform;
- and
- a complementary output generator (COG) having an input coupled to an output of the voltage comparator and a plurality of outputs controlled by the output of the voltage comparator and configured to drive a driver stage coupled with the load.
An integrated circuit microcontroller having a class D power driver peripheral, comprising:
- a digital processor and memory;
- a digital-to-analog converter (DAC) having inputs coupled to the digital processor;
- a voltage comparator having a first input coupled to an output of the DAC;
- a capacitive sensing module (CSM) having an output coupled to a second input of the voltage comparator and in input coupled to an external capacitor, wherein the CSM provides a triangle waveform output to the voltage comparator and the external capacitor determines a frequency of the triangle waveform;
- a complementary output generator (COG) having an input coupled to an output of the voltage comparator and a plurality of outputs controlled by the output of the voltage comparator;
- a differential amplifier having first and second inputs adapted for coupling to a load driven by the COG;
- an operational amplifier having a first input coupled to an output of the differential amplifier and a second input coupled to the analog voltage, wherein an output of the operational amplifier is coupled to the first input of the voltage comparator instead of the analog voltage;
- and
- a closed loop compensation circuit coupled with the operational amplifier.
A method for providing a class D power driver peripheral said method comprising the steps of:
- comparing within a microcontroller an analog voltage to a triangle waveform with a voltage comparator, wherein the triangle waveform is provided from a capacitive sensing module (CSM) within the microcontroller;
- feeding a pulse width modulation (PWM) waveform resulting from the comparison of the analog voltage and the triangle waveform to a complementary output generator (COG) within the microcontroller;
- generating PWM signals with the COG within the microcontroller to control an H-bridge connected plurality of power metal oxide semiconductor field effect transistors (MOSFETs);
- coupling a differential amplifier within the microcontroller to the load;
- coupling an operational amplifier within the microcontroller to the differential amplifier and the analog voltage;
- and
- coupling the operational amplifier to the CSM, wherein the differential amplifier and operational amplifier provide feedback from the load for improved power delivery regulation to the load.
Dependencies are inferred from the claim text.