Himax Analogic, Inc.

Amazion Electronics, Inc.

Other

Kuo-Hung Wu

Po-Yu Li

Kwang-Hwa Liu

Kuan-Jen Tseng

Cheng-Nan Wu

Tyng-Yang Chen

Jun-Nian Lin

Zhi-Yu Zhuang

Kuan-Po Hsueh

A current sense circuit includes a power transistor, a first level shifter, an operational transconductance amplifier (OTA), a second level shifter, and a dummy transistor. The power transistor has a first terminal and a power control terminal coupled to a control voltage. The first level shifter is coupled to the first terminal and pulls up a voltage of the first terminal to an operating voltage. The OTA is coupled to the first level shifter and converts the operating voltage into an operating current. The second level shifter is coupled to the OTA and pulls down the operating voltage to the voltage of the first terminal. The dummy transistor has a dummy control terminal with the control voltage, and a third terminal coupled to the second level shifter and having the same voltage as the voltage of the first terminal.

DC/DC converter and current sense circuit thereof

A slope compensation circuit includes a first differential pair circuit, a current mirror unit, a first operating current generation circuit, and a transconductance compensation circuit. The first differential pair circuit is connected to a first current source and receives a pair of differential oscillation signals to generate a pair of differential currents corresponding to the differential oscillation signals. The current mirror unit is connected to the first differential pair circuit and mirrors the differential currents. The first operating current generation circuit is connected to the current mirror unit and generates a first operating current including the differential currents. The transconductance compensation circuit stabilizes a quiescent operating point of the first operating current generation circuit and receives the differential oscillation signals to generate an output current multiple times the value of the first operating current.

DC/DC converter and slope compensation circuit thereof

A power amplifier with noise shaping function is provided. The power amplifier includes a differential mode integrator, an integration and adjustment unit and a switch unit. The differential mode integrator is used for receiving a differential mode input signal and a differential mode output signal, and outputting a differential mode first signal. The integration and adjustment unit is coupled to the differential mode integrator for receiving the first signal and an output signal and outputting a single-end mode second signal. The switch unit is used for receiving the second signal and outputting the differential mode output signal to drive the load. The present invention uses a common mode input signal instead of the single-end input signal to eliminate the common mode noise, and uses a 2-order (or more than that) integrating circuit instead of the conventional filter to achieve a preferred effect of reducing the off band noise.

Power amplifier with noise shaping function

A preset circuit of an audio power amplifier includes an inverter and a voltage drop device. The inverter receives an input signal to output an output signal, and includes a first switch and a second switch. The first switch is controlled with the input signal, and has a first terminal coupled to a power voltage and a second terminal for outputting the output signal. The second switch is controlled with the input signal, and has a third terminal for outputting the output signal and a fourth terminal coupled to a low reference voltage. The voltage drop device is coupled between the first terminal of the first switch and the power voltage and configured to lower the power voltage. The output signal is kept at a low level when the voltage drop device and the first switch are de-actuated due to the power voltage having a level below a first threshold.

Preset circuit of audio power amplifier

The invention provides a switching audio power amplifier with de-noise function, including a first comparator, a second comparator, a logic control unit, a de-noise circuit, and a bridge circuit. The first comparator and the second comparator respectively generate the first PWM signal and the second PWM signal, and then the logic control unit performs logic operation to generate a third PWM signal and a fourth PWM signal. If the pulse width of the third PWM signal (or the fourth PWM signal) is lower than a threshold, the de-noise circuit increases the pulse width of the third PWM signal or the fourth PWM signal and outputs the fifth PWM signal and the sixth PWM signal to drive the bridge circuit. Next, the bridge circuit conducts a driving current alternately flowing to and from a load according to the firth PWM signal and the sixth PWM signal.

Switching audio power amplifier with de-noise function

A semiconductor device includes a first metal region, a plurality of vias, a plurality of second metal regions, a plurality of openings and a third metal region. The first metal region conducts source/drain current. The second metal regions are electrically connected to the first metal region through the vias for conducting the source/drain current, in which each of the second metal regions is disposed in a distance from the adjacent second metal regions. The third metal region is electrically connected to the second metal regions through the openings, in which the resistance of the third metal region is smaller than the resistances of the first metal region and the second metal regions.

Semiconductor device

An audio power amplifier package includes a non-signal lead, a first non-signal pad, a second non-signal pad and a plurality of bonding wires. The first non-signal pad and the second non-signal pad are disposed on a substrate. The bonding wires connect the non-signal lead to the first non-signal pad and the second non-signal pad respectively.

Audio power amplifier package

A power amplifier with noise shaping is disclosed. The power amplifier with noise shaping is able to minimize the noise interference a regular power amplifier encounters. The power amplifier includes a differential-mode integrator, a driving unit, and a low pass filter and integration unit. The differential-mode integrator receives a differential-mode input signal and a differential-mode feedback signal and performs integration operations to output a differential-mode intermediate signal. The driving unit outputs a differential-mode output signal and drives a load according to the differential-mode intermediate signal. The low pass filter and integration unit performs a filtering operation on the differential-mode output signal and integration operations to output the differential-mode feedback signal to the differential-mode integrator.

Power amplifier with noise shaping

A driving circuit to drive an output stage comprising a high side NMOS and a low side NMOS is provided. The driving circuit comprises: a diode comprising an anode and a cathode, wherein the anode is electrically connected to a first voltage source and the sources of a first and a second PMOS; a third and a fourth PMOS both comprising a drain, a source and a gate, wherein the sources are respectively connected to the gates of the second and first PMOS, the drains are respectively connected to the drains of the first and second PMOS. A first and a second NMOS both comprise a drain, a source and a gate, wherein the drains are respectively connected to the drain of the fourth and third PMOS, the sources are coupled to a second voltage source, the gates are respectively connected to a first input and a second input.

Driving circuit to drive an output stage

The invention provides a switching audio power amplifier with de-noise function including a pulse width modulator, a de-noise circuit and a bridge circuit. The pulse width modulator performs pulse width moderation to generate the first and second PWM signals according to an input audio signal. The de-noise circuit receives the first and second PWM signals. And the bridge circuit conducts a driving current alternately flowing to and from a load according to the control signals output from the de-noise circuit.

An audio system with power-on/off noise suppression and an audio amplifier thereof are disclosed. The audio system includes a front stage circuit and an audio amplifier. The front stage circuit is powered by a first supply voltage and outputs an audio signal. The audio amplifier amplifies the audio signal to drive a load. When a level of the first supply voltage drops below a threshold, the audio amplifier is disabled.

Audio system with power-on/off noise suppression and audio amplifier thereof

A circuit and a method for controlling the power mode of a class-D amplifier are provided. The power mode control circuit comprises an amplitude detector and a duration detector. The amplitude detector provides an amplitude signal according to the absolute signal level of an input signal. The duration detector provides a shut-down signal to a switching control circuit of a class-D amplifier according to the length of the time period in which the amplitude signal is at a predetermined state, wherein the switching control circuit is turned on or turned off in response to the shut-down signal.

Circuit and method for controlling the power mode a class-D amplifier

A double reference wave modulation scheme for filterless power amplifiers is disclosed for reducing EMI. In the filterless power amplifier, differential outputs for driving load impedance are corrected based on input audio signals by the error amplifier. Reference wave generators generate reference waves. Comparators are responsive to the reference waves and the input audio signal. Operation states of the switching unit are decided based on output signals of the comparators and the switching unit output the differential output. Besides, a feedback unit feeds the differential output back to the error amplifier. By this configuration, complex control logic is not needed.

Filterless class D power amplifier

A double reference wave modulation scheme for filterless power amplifiers is disclosed for reducing EMI and common mode voltages. In the filterless power amplifier, differential outputs for driving load impedance are feedback and corrected based on input audio signals. Reference wave generators generate reference waves. A control logic results pulses in the pair of differential outputs in response to a clock signal or a reference voltage and a cross relationship between the input audio signal and the first and second reference waves. Pulses of one of the differential outputs are not overlapped with pulses of the other of the differential outputs for eliminating common mode noises of the power amplifier.

Growing community of inventors

Tainan County, Taiwan

Kuo-Hung Wu