| 摘要 |
A low frequency PWM output bridge amplifier having an input network configurable for standard PWM digital input signals, phase shift PWM digital input signals or analog input signals and for standard PWM output or phase shift PWM output is provided. The amplifier includes two identical amplifying modules. One for the amplifying channel relative to the direct or positive PWM output and the other for the amplifying channel relative to the inverted or negative PWM output. Each module includes a switching output operational amplifier, having a voltage mode noninverting input, a current mode inverting input and a loop filter implementing a single or multiple slope integrator outputting a signal of a substantially triangular waveform. Each module also includes a logic inverter or a cascade of logic inverters coupled in cascade to the output of the integrator and outputting a logic PWM signal, an output power stage converting the logic PWM signal output by the inverter(s) in a PWM signal, switching between the potentials of the two supply rails of the circuit, and a feedback resistor connecting the output of power stage to the inverting input of the operational amplifier.
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