Current controlled pulse width modulation circuit and class-D amplifier comprising the same
AssigneeSamsung Electronics Co., Ltd.
InventorsJong-Haeng Lee, Jeoung-In Lee
Life of this patent
Estimating the term…
Abstract
A pulse width modulation (PWM) circuit comprising an input circuit, first and second controllers, and first and second Schmidt triggers. The first controller sets a first voltage level by a first current generated responding to an input signal and an output of the input circuit. The first Schmidt trigger sets a first logic level when an output of the first controller reaches the first voltage level. The second controller sets a second voltage level by a second current generated responding to the input signal and an output of the first Schmidt trigger. The second Schmidt trigger generates a PWM output signal with a variable frequency in accordance with the first and second currents.
Claims20
A pulse width modulation (PWM) circuit comprising:
- an input circuit receiving a PWM output signal;
- a first controller for generating an output of a first voltage level by a first current in response to an input signal and an output of the input circuit;
- a first Schmidt trigger for generating an output of a first logic level when the output of the first controller reaches the first voltage level;
- a second controller for generating an output of a second voltage level by a second current in response to the input signal and the output of the first Schmidt trigger;
- and
- a second Schmidt trigger for generating the PWM output signal whose frequency is variable in accordance with the first and second currents.
A class-D amplifier for generating an audio output signal from an audio input signal, comprising:
- a pulse width modulation (PWM) circuit for generating a PWM output signal by a current from a voltage difference between the audio input signal and a gain-amplified signal;
- negative channel metal oxide semiconductor (NMOS) and positive channel metal oxide semiconductor (PMOS) transistors for responding to the PWM output signal;
- a loop filter for demodulating a signal driven by the PMOS and NMOS transistors;
- and
- a gain amplifier for generating the gain-amplified signal by amplifying an output of the loop filter.
A pulse width modulation (PWM) circuit comprising:
- a first controller coupled to a first Schmidt trigger, wherein the first controller receives an input signal and an inverted output signal;
- and
- a second controller coupled to a second Schmidt trigger, wherein the second controller receives an inverted input signal and an output having a first logic level, wherein the second Schmidt trigger generates an output signal having a variable frequency.
Dependencies are inferred from the claim text.