摘要:
Class-D amplifiers have evolved from using binary pulse-width modulation (PWM) modulators to three-level PWM modulators. Three-level PWM drivers for audio applications offer the benefits of eliminating costly elements at the output of an audio system. However, they also introduce increased common-mode interference. Three-level PWM generates three states, but one state has two interchangeable representations which can be scrambled in order to shape the common-mode output spectrum.
摘要:
An apparatus for detecting and controlling current. A current detector for generating a first value that represents an amount of current being delivered to a device. A current limit circuit for generating a second value that represents a maximum permitted current level from a current source. A current controller for controlling the amount of current drawn by the device if the first value exceeds the second value.
摘要:
An apparatus for detecting and controlling current. A current detector for generating a first value that represents an amount of current being delivered to a device. A current limit circuit for generating a second value that represents a maximum permitted current level from a current source. A current controller for controlling the amount of current drawn by the device if the first value exceeds the second value.
摘要:
A battery assisted level shifter comprises a pull up transistor pulling up an output when a received input signal is high, a pull down transistor pulling down the output when the received input signal is low, and a battery element to provide voltage offsets. The battery element can be implemented using one or more pull-up transistors for assisting with pulling up the output. The level shifter can be used in class-D amplifiers, DC-DC power converters and interfaces between circuits having different reference voltages.
摘要:
An apparatus for detecting and controlling current. A current detector for generating a first value that represents an amount of current being delivered to a device. A current limit circuit for generating a second value that represents a maximum permitted current level from a current source. A current controller for controlling the amount of current drawn by the device if the first value exceeds the second value.
摘要:
A level shifter comprising a first driver transistor receiving an input signal. A gate-controlled transistor coupled to the first driver transistor. A second driver transistor coupled to the gate controlled transistor. An output coupled to the second driver transistor, wherein the gate-controlled transistor is for receiving a predetermined gate voltage when the output voltage exceeds a predetermined value.
摘要:
A battery assisted level shifter comprises a pull up transistor pulling up an output when a received input signal is high, a pull down transistor pulling down the output when the received input signal is low, and a battery element to provide voltage offsets. The battery element can be implemented using one or more pull-up transistors for assisting with pulling up the output. The level shifter can be used in class-D amplifiers, DC-DC power converters and interfaces between circuits having different reference voltages.
摘要:
A level shifter comprising a first driver transistor receiving an input signal. A gate-controlled transistor coupled to the first driver transistor. A second driver transistor coupled to the gate controlled transistor. An output coupled to the second driver transistor, wherein the gate-controlled transistor is for receiving a predetermined gate voltage when the output voltage exceeds a predetermined value.
摘要:
A triangular waveform generator is converted to a free running oscillator controlled by a calibration code. The free running oscillator can be synchronized to an external clock signal by comparing the external clock frequency to the frequency of the triangular waveform and adjusting the calibration code until the discrepancy in frequency is minimized.
摘要:
In today's environment class-D amplifiers are used to provide an integrated solution for applications such as powered audio devices due to their advantages in power consumption and size over more traditional analog amplifiers. Due to power output requirements, the output stages of power drivers such as class-D amplifiers require a supply voltage in excess of the technologically allowed voltage for the switches in the output stage. A level shifter is used to ensure voltages supplied to the output switches do not exceed the technological limits. An ideal level shifter should provide the optimal voltage swing to output switches under all process, supply voltage and temperature (PVT) variations. The ideal level shifter should also provide fast transitions when the control signal changes from high to low and low to high.