Abstract: Systems and methods implemented in a switching amplifier for providing consistent, matching switching between top and bottom switching devices in a switching amplifier. One embodiment includes a half-bridge circuit output stage, a driver stage and a transformer. The driver stage, which drives the switches of the output stage, is very fast, has a low propagation delay, and has minimal input capacitance. The transformer drives the drive paths from the transformer inputs to the switches. The transformer avoids resonances within the audio band and at the amplifier switching frequencies, has low and spread free leakage inductance, has enough magnetizing inductance to keep transformer currents low in proportion to the total driver stage current drain, has low core losses at the switching frequency, has minimal inductance change and operates well below its saturation point. The amplifier stage provides a substantially constant amplitude drive signal to the output power switching devices.

Abstract: Systems and methods implemented in a switching amplifier for providing consistent, matching switching between top and bottom switching devices in a switching amplifier. One embodiment includes a half-bridge circuit output stage, a driver stage and a transformer. The driver stage, which drives the switches of the output stage, is very fast, has a low propagation delay, and has minimal input capacitance. The transformer drives the drive paths from the transformer inputs to the switches. The transformer avoids resonances within the audio band and at the amplifier switching frequencies, has low and spread free leakage inductance, has enough magnetizing inductance to keep transformer currents low in proportion to the total driver stage current drain, has low core losses at the switching frequency, has minimal inductance change and operates well below its saturation point. The amplifier stage provides a substantially constant amplitude drive signal to the output power switching devices.

Abstract: Systems and methods for controlling amplification of a pair of pulse width modulated signals. In one embodiment, a system comprises an audio amplifier which is configured to receive a pulse code modulated (PCM) input signal, convert this signal to a pulse width modulated (PWM) signal in a controller, and amplify the PWM signal in an output stage. The controller separates the PWM signal into a high-side signal and a low-side signal. The controller incorporates digitally programmable delays into the processing paths for each of the high-side and low-side signals. The high-side and low-side signals are separately provided to the output stage. The separate high-side and low-side signals can be used to individually control (e.g., turn off) the high-side and low-side transistors. Circuitry is included to generate a short low-side pulse when both transistors are turned off in order to drain the gate charge from the high-side transistor.

Abstract: An electric circuit comprising a transformer having first and second magnetically coupled inductors, a first switch which is connected to the first inductor, a second switch which is connected to the second inductor so as to be turned on and off by the second inductor; and a timing circuit for connection to the first switch for turning the first switch on and off. The second inductor is magnetically coupled to the first inductor such that flux reversal in the first inductor which occurs as the first switch is turned off will induce flux reversal in the second inductor which will thereby turn on the second switch. The circuit includes a damping element arranged to damp the operation of the second switch.

Abstract: The converter is a switch mode converter in which a primary transformer winding (12) is switched by a power switch (Q5). The transformer secondary is wound with a power output winding (14) and a reference winding (29). The power switch (Q5) is operated by IC (24) connected as a ring-of-three oscillator. Regulation is achieved by two feedback means. First, the voltage on the reference winding (29) is peak rectified and fed back (30) to control the oscillator (24). Secondly, a signal which is a function of the on-time of the power switch (Q5) modifies the operation of a reference voltage source (Q1, Q2). The converter is particularly adapted to operate over a wide range of input voltages (typically 24 V-60 V) and over a wide range of low power (typically 24 mW-850 mW).

Abstract: An integrated, non-coupled structure comprises a body of ferrite material with a plurality of through passages. A plurality of conductors pass through respective ones of the passages to form windings, certain of which have no magnetic field coupling and hence provide separate non-coupled magnetic functions. The magnetic structure is used as a component of a switching dc-to-dc converter, integrating the functions of isolation transformer, output filter and feedback signal coupling.

Abstract: In a digitally controlled amplifier circuit a dc power source is modulated by an oscillator signal for producing a reference square wave signal. A sawtooth signal, double the frequency of the reference signal and synchronized therewith, is compared with a variable input signal to be amplified. When the sawtooth exceeds the input signal a phase shifted version of the reference signal, shifted in phase in accord with the instantaneous amplitude of the variable signal is produced. A switching circuit logically governed by the reference and phase shifted signals produce a pulse width modulated output signal of a selected polarity. An output filter smooths the pulse width modulated output signal and steering diodes control the polarity of the switching circuit.

Abstract: A switching inverter power supply has a harmonic semi-resonant circuit associated with an isolation transformer for reducing electromagnetic interference. Fixed-frequency operation with pulse width modulation for regulation is accompanied by controlled current rise and fall times in the transformer primary. The semi-resonant circuit comprises an inductor in series with the transformer primary and a capacitor in parallel with the transformer secondary, transformer leakage inductance being included in the resonance. In one version, the resonant frequency can be set from about the fifth to about the twentieth harmonic of the fixed switching frequency for reducing peak switching currents.

Abstract: A pulse width modulated signal amplifier includes first and second switching transistors and a diode which are connected in series across a DC power source and in the forward direction with respect to the polarity of the DC power source, the diode being connected between the first and second transistors. The first transistor has its base connected to a corresponding terminal of the DC power source and the second transistor has its base supplied with a pulse width modulated signal to be amplified. A connection point of the first transistor and a diode is connected to a lowpass filter which provides a demodulated audio signal to a load. A coil is connected between the diode and the second transistor and the connection point of the coil and the second transistor is connected to the base of first transistor.

Abstract: In a Class D amplifier system comprising a pulse width modulator for pulse width modulating with an audio signal a carrier signal having a frequency higher than that of the audio signal, an output switching amplifier connected to the modulator, and a lowpass filter connected to the output amplifier to supply a demodulated audio signal to a load in which a trap circuit resonant at a carrier signal frequency is provided in the lowpass filter to permit part of an output signal from the trap circuit which is free from a carrier signal component to be negative-fed back to the pulse width modulator.